Merge branch 'master' of https://github.com/adambard/learnxinyminutes-docs

asymptotic-notation.html.markdown

@@ -155,7 +155,7 @@ Small-o, commonly written as **o**, is an Asymptotic Notation to denote the
 upper bound (that is not asymptotically tight) on the growth rate of runtime 
 of an algorithm.
 
-`f(n)` is o(g(n)), if for some real constants c (c > 0) and n<sub>0</sub> (n<sub>0</sub> > 0), `f(n)` is < `c g(n)` 
+`f(n)` is o(g(n)), if for all real constants c (c > 0) and n<sub>0</sub> (n<sub>0</sub> > 0), `f(n)` is < `c g(n)` 
 for every input size n (n > n<sub>0</sub>).
 
 The definitions of O-notation and o-notation are similar. The main difference 
@@ -168,7 +168,7 @@ Small-omega, commonly written as **ω**, is an Asymptotic Notation to denote
 the lower bound (that is not asymptotically tight) on the growth rate of 
 runtime of an algorithm.
 
-`f(n)` is ω(g(n)), if for some real constants c (c > 0) and n<sub>0</sub> (n<sub>0</sub> > 0), `f(n)` is > `c g(n)` 
+`f(n)` is ω(g(n)), if for all real constants c (c > 0) and n<sub>0</sub> (n<sub>0</sub> > 0), `f(n)` is > `c g(n)` 
 for every input size n (n > n<sub>0</sub>).
 
 The definitions of Ω-notation and ω-notation are similar. The main difference 

bash.html.markdown

@@ -25,7 +25,7 @@ Nearly all examples below can be a part of a shell script or executed directly i
 [Read more here.](http://www.gnu.org/software/bash/manual/bashref.html)
 
 ```bash
-#!/bin/bash
+#!/usr/bin/env bash
 # First line of the script is shebang which tells the system how to execute
 # the script: http://en.wikipedia.org/wiki/Shebang_(Unix)
 # As you already figured, comments start with #. Shebang is also a comment.

citron.html.markdown

@@ -0,0 +1,212 @@
+---
+language: citron
+filename: learncitron.ctr
+contributors:
+    - ["AnotherTest", ""]
+lang: en-us
+---
+```ruby
+# Comments start with a '#'
+# All comments encompass a single line
+
+###########################################
+## 1. Primitive Data types and Operators
+###########################################
+
+# You have numbers
+3. # 3
+
+# Numbers are all doubles in interpreted mode
+
+# Mathematical operator precedence is not respected.
+# binary 'operators' are evaluated in ltr order
+1 + 1. # 2
+8 - 4. # 4
+10 + 2 * 3. # 36
+
+# Division is always floating division
+35 / 2 # 17.5.
+
+# Integer division is non-trivial, you may use floor
+(35 / 2) floor # 17.
+
+# Booleans are primitives
+True.
+False.
+
+# Boolean messages
+True not. # False
+False not. # True
+1 = 1. # True
+1 !=: 1. # False
+1 < 10. # True
+
+# Here, `not` is a unary message to the object `Boolean`
+# Messages are comparable to instance method calls
+# And they have three different forms:
+#   1. Unary messages: Length > 1, and they take no arguments:
+        False not.
+#   2. Binary Messages: Length = 1, and they take a single argument:
+        False & True.
+#   3. Keyword messages: must have at least one ':', they take as many arguments
+#      as they have `:` s
+        False either: 1 or: 2. # 2
+
+# Strings
+'This is a string'.
+'There are no character types exposed to the user'.
+# "You cannot use double quotes for strings" <- Error
+
+# Strins can be summed
+'Hello, ' + 'World!'. # 'Hello, World!'
+
+# Strings allow access to their characters
+'This is a beautiful string' at: 0. # 'T'
+
+###########################################
+## intermission: Basic Assignment
+###########################################
+
+# You may assign values to the current scope:
+var name is value. # assignes `value` into `name`
+
+# You may also assign values into the current object's namespace
+my name is value. # assigns `value` into the current object's `name` property
+
+# Please note that these names are checked at compile (read parse if in interpreted mode) time
+# but you may treat them as dynamic assignments anyway
+
+###########################################
+## 2. Lists(Arrays?) and Tuples
+###########################################
+
+# Arrays are allowed to have multiple types
+Array new < 1 ; 2 ; 'string' ; Nil. # Array new < 1 ; 2 ; 'string' ; Nil
+
+# Tuples act like arrays, but are immutable.
+# Any shenanigans degrade them to arrays, however
+[1, 2, 'string']. # [1, 2, 'string']
+
+# They can interoperate with arrays
+[1, 'string'] + (Array new < 'wat'). # Array new < 1 ; 'string' ; 'wat'
+
+# Indexing into them
+[1, 2, 3] at: 1. # 2
+
+# Some array operations
+var arr is Array new < 1 ; 2 ; 3.
+
+arr head. # 1
+arr tail. # Array new < 2 ; 3.
+arr init. # Array new < 1 ; 2.
+arr last. # 3
+arr push: 4. # Array new < 1 ; 2 ; 3 ; 4.
+arr pop. # 4
+arr pop: 1. # 2, `arr` is rebound to Array new < 1 ; 3.
+
+# List comprehensions
+[x * 2 + y,, arr, arr + [4, 5],, x > 1]. # Array ← 7 ; 9 ; 10 ; 11
+# fresh variable names are bound as they are encountered,
+# so `x` is bound to the values in `arr`
+# and `y` is bound to the values in `arr + [4, 5]`
+#
+# The general format is: [expr,, bindings*,, predicates*]
+
+
+####################################
+## 3. Functions
+####################################
+
+# A simple function that takes two variables
+var add is {:a:b ^a + b.}.
+
+# this function will resolve all its names except the formal arguments
+# in the context it is called in.
+
+# Using the function
+add applyTo: 3 and: 5. # 8
+add applyAll: [3, 5]. # 8
+
+# Also a (customizable -- more on this later) pseudo-operator allows for a shorthand
+# of function calls
+# By default it is REF[args]
+
+add[3, 5]. # 8
+
+# To customize this behaviour, you may simply use a compiler pragma:
+#:callShorthand ()
+
+# And then you may use the specified operator.
+# Note that the allowed 'operator' can only be made of any of these: []{}()
+# And you may mix-and-match (why would anyone do that?)
+
+add(3, 5). # 8
+
+# You may also use functions as operators in the following way:
+
+3 `add` 5. # 8
+# This call binds as such: add[(3), 5]
+# because the default fixity is left, and the default precedance is 1
+
+# You may change the precedence/fixity of this operator with a pragma
+#:declare infixr 1 add
+
+3 `add` 5. # 8
+# now this binds as such: add[3, (5)].
+
+# There is another form of functions too
+# So far, the functions were resolved in a dynamic fashion
+# But a lexically scoped block is also possible
+var sillyAdd is {\:x:y add[x,y].}.
+
+# In these blocks, you are not allowed to declare new variables
+# Except with the use of Object::'letEqual:in:`
+# And the last expression is implicitly returned.
+
+# You may also use a shorthand for lambda expressions
+var mul is \:x:y x * y.
+
+# These capture the named bindings that are not present in their
+# formal parameters, and retain them. (by ref)
+
+###########################################
+## 5. Control Flow
+###########################################
+
+# inline conditional-expressions
+var citron is 1 = 1 either: 'awesome' or: 'awful'. # citron is 'awesome'
+
+# multiple lines is fine too
+var citron is 1 = 1
+    either: 'awesome'
+    or:     'awful'.
+
+# looping
+10 times: {:x
+    Pen writeln: x.
+}. # 10. -- side effect: 10 lines in stdout, with numbers 0 through 9 in them
+
+# Citron properly supports tail-call recursion in lexically scoped blocks
+# So use those to your heart's desire
+
+# mapping most data structures is as simple as `fmap:`
+[1, 2, 3, 4] fmap: \:x x + 1. # [2, 3, 4, 5]
+
+# You can use `foldl:accumulator:` to fold a list/tuple
+[1, 2, 3, 4] foldl: (\:acc:x acc * 2 + x) accumulator: 4. # 90
+
+# That expression is the same as
+(2 * (2 * (2 * (2 * 4 + 1) + 2) + 3) + 4)
+
+###################################
+## 6. IO
+###################################
+
+# IO is quite simple
+# With `Pen` being used for console output
+# and Program::'input' and Program::'waitForInput' being used for console input
+
+Pen writeln: 'Hello, ocean!' # prints 'Hello, ocean!\n' to the terminal
+
+Pen writeln: Program waitForInput. # reads a line and prints it back
+```

common-lisp.html.markdown

@@ -16,7 +16,7 @@ popular and recent book is [Land of Lisp](http://landoflisp.com/). A new book ab
 
 
 
-```common-lisp
+```lisp
 
 ;;;-----------------------------------------------------------------------------
 ;;; 0. Syntax

cs-cz/markdown.html.markdown

@@ -13,7 +13,7 @@ Markdown byl vytvořen Johnem Gruberem v roce 2004. Je zamýšlen jako lehce či
 a psatelná syntaxe, která je jednoduše převeditelná do HTML (a dnes i do mnoha
 dalších formátů)
 
-```markdown
+```md
 <!-- Markdown je nadstavba nad HTML, takže jakýkoliv kód HTML je validní
 Markdown, to znamená, že můžeme používat HTML elementy, třeba jako komentář, a
 nebudou ovlivněny parserem Markdownu. Avšak, pokud vytvoříte HTML element v

cypher.html.markdown

@@ -16,19 +16,19 @@ Nodes
 
 **Represents a record in a graph.**
 
-```()```
+`()`
 It's an empty *node*, to indicate that there is a *node*, but it's not relevant for the query.
 
-```(n)```
+`(n)`
 It's a *node* referred by the variable **n**, reusable in the query. It begins with lowercase and uses camelCase.
 
-```(p:Person)```
+`(p:Person)`
 You can add a *label* to your node, here **Person**. It's like a type / a class / a category. It begins with uppercase and uses camelCase.
 
-```(p:Person:Manager)```
+`(p:Person:Manager)`
 A node can have many *labels*.
 
-```(p:Person {name : 'Théo Gauchoux', age : 22})```
+`(p:Person {name : 'Théo Gauchoux', age : 22})`
 A node can have some *properties*, here **name** and **age**. It begins with lowercase and uses camelCase.
 
 The types allowed in properties :
@@ -40,7 +40,7 @@ The types allowed in properties :
 
 *Warning : there isn't datetime property in Cypher ! You can use String with a specific pattern or a Numeric from a specific date.*
 
-```p.name```
+`p.name`
 You can access to a property with the dot style.
 
 
@@ -49,16 +49,16 @@ Relationships (or Edges)
 
 **Connects two nodes**
 
-```[:KNOWS]```
+`[:KNOWS]`
 It's a *relationship* with the *label* **KNOWS**. It's a *label* as the node's label. It begins with uppercase and use UPPER_SNAKE_CASE.
 
-```[k:KNOWS]```
+`[k:KNOWS]`
 The same *relationship*, referred by the variable **k**, reusable in the query, but it's not necessary.
 
-```[k:KNOWS {since:2017}]```
+`[k:KNOWS {since:2017}]`
 The same *relationship*, with *properties* (like *node*), here **since**.
 
-```[k:KNOWS*..4]```
+`[k:KNOWS*..4]`
 It's a structural information to use in a *path* (seen later). Here, **\*..4** says "Match the pattern, with the relationship **k** which be repeated between 1 and 4 times.
 
 
@@ -67,16 +67,16 @@ Paths
 
 **The way to mix nodes and relationships.**
 
-```(a:Person)-[:KNOWS]-(b:Person)```
+`(a:Person)-[:KNOWS]-(b:Person)`
 A path describing that **a** and **b** know each other.
 
-```(a:Person)-[:MANAGES]->(b:Person)```
+`(a:Person)-[:MANAGES]->(b:Person)`
 A path can be directed. This path describes that **a** is the manager of **b**.
 
-```(a:Person)-[:KNOWS]-(b:Person)-[:KNOWS]-(c:Person)```
+`(a:Person)-[:KNOWS]-(b:Person)-[:KNOWS]-(c:Person)`
 You can chain multiple relationships. This path describes the friend of a friend.
 
-```(a:Person)-[:MANAGES]->(b:Person)-[:MANAGES]->(c:Person)```
+`(a:Person)-[:MANAGES]->(b:Person)-[:MANAGES]->(c:Person)`
 A chain can also be directed. This path describes that **a** is the boss of **b** and the big boss of **c**.
 
 Patterns often used (from Neo4j doc) :
@@ -230,13 +230,13 @@ DELETE n, r
 Other useful clauses
 ---
 
-```PROFILE```
+`PROFILE`
 Before a query, show the execution plan of it.
 
-```COUNT(e)```
+`COUNT(e)`
 Count entities (nodes or relationships) matching **e**.
 
-```LIMIT x```
+`LIMIT x`
 Limit the result to the x first results.
 
 

es-es/markdown-es.html.markdown

@@ -14,7 +14,7 @@ fácilmente a HTML (y, actualmente, otros formatos también).
 ¡Denme toda la retroalimentación que quieran! / ¡Sientanse en la libertad de hacer forks o pull requests!
 
 
-```markdown
+```md
 <!-- Markdown está basado en HTML, así que cualquier archivo HTML es Markdown
 válido, eso significa que podemos usar elementos HTML en Markdown como, por
 ejemplo, el comentario y no serán afectados por un parseador Markdown. Aún 

es-es/objective-c-es.html.markdown

@@ -13,7 +13,7 @@ Objective C es el lenguaje de programación principal utilizado por Apple para l
 Es un lenguaje de programación para propósito general que le agrega al lenguaje de programación C una mensajería estilo "Smalltalk".
 
 
-```objective_c
+```objectivec
 // Los comentarios de una sola línea inician con //
 
 /*

es-es/visualbasic-es.html.markdown

@@ -10,7 +10,7 @@ filename: learnvisualbasic-es.vb
 lang: es-es
 ---
 
-```vb
+```
 Module Module1
 
     Sub Main()

fi-fi/markdown-fi.html.markdown

@@ -10,7 +10,7 @@ lang: fi-fi
 
 John Gruber loi Markdownin vuona 2004. Sen tarkoitus on olla helposti luettava ja kirjoitettava syntaksi joka muuntuu helposti HTML:ksi (ja nyt myös moneksi muuksi formaatiksi).
 
-```markdown
+```md
 <!-- Jokainen HTML-tiedosto on pätevää Markdownia. Tämä tarkoittaa että voimme
 käyttää HTML-elementtejä Markdownissa, kuten kommentteja, ilman että markdown
 -jäsennin vaikuttaa niihin. Tästä johtuen et voi kuitenkaan käyttää markdownia

fr-fr/jquery-fr.html.markdown

@@ -138,5 +138,5 @@ $('p').each(function() {
 });
 
 
-``
+```
 

go.html.markdown

@@ -15,15 +15,15 @@ contributors:
 ---
 
 Go was created out of the need to get work done. It's not the latest trend
-in computer science, but it is the newest fastest way to solve real-world
+in programming language theory, but it is a way to solve real-world
 problems.
 
-It has familiar concepts of imperative languages with static typing.
+It draws concepts from imperative languages with static typing.
 It's fast to compile and fast to execute, it adds easy-to-understand
-concurrency to leverage today's multi-core CPUs, and has features to
+concurrency because multi-core CPUs are now common, and it's used successfully
-help with large-scale programming.
+in large codebases (~100 million loc at Google, Inc.).
 
-Go comes with a great standard library and an enthusiastic community.
+Go comes with a good standard library and a sizeable community.
 
 ```go
 // Single line comment
@@ -48,7 +48,7 @@ import (
 // executable program. Love it or hate it, Go uses brace brackets.
 func main() {
 	// Println outputs a line to stdout.
-	// Qualify it with the package name, fmt.
+	// It comes from the package fmt.
 	fmt.Println("Hello world!")
 
 	// Call another function within this package.

id-id/markdown.html.markdown

@@ -13,7 +13,7 @@ Markdown dibuat oleh John Gruber pada tahun 2004. Tujuannya untuk menjadi syntax
 Beri masukan sebanyak-banyaknya! / Jangan sungkan untuk melakukan fork dan pull request!
 
 
-```markdown
+```md
 <!-- Markdown adalah superset dari HTML, jadi setiap berkas HTML adalah markdown yang
 valid, ini berarti kita dapat menggunakan elemen HTML dalam markdown, seperti elemen
 komentar, dan ia tidak akan terpengaruh parser markdown. Namun, jika Anda membuat

it-it/markdown.html.markdown

@@ -28,7 +28,7 @@ Markdown varia nelle sue implementazioni da un parser all'altro. Questa guida ce
 ## Elementi HTML
 Markdown è un superset di HTML, quindi ogni file HTML è a sua volta un file Markdown valido.
 
-```markdown
+```md
 <!-- Questo significa che possiamo usare elementi di HTML in Markdown, come per esempio i commenti,
 e questi non saranno modificati dal parser di Markdown. State attenti però, 
 se inserite un elemento HTML nel vostro file Markdown, non potrete usare la sua sintassi 

it-it/python3-it.html.markdown

@@ -400,8 +400,8 @@ else:                  # Anche else è opzionale
     print("some_var è  10.")
 
 """
-I cicli for iterano sulle liste, cioé ripetono un codice per ogni elemento 
+I cicli for iterano sulle liste, cioè ripetono un codice per ogni elemento 
-# di una lista.
+di una lista.
 Il seguente codice scriverà:
     cane è un mammifero
     gatto è un mammifero
@@ -409,7 +409,7 @@ Il seguente codice scriverà:
 """
 for animale in ["cane", "gatto", "topo"]:
     # Puoi usare format() per interpolare le stringhe formattate.
-    print("{} is a mammal".format(animal))
+    print("{} è un mammifero".format(animale))
 
 """
 "range(numero)" restituisce una lista di numeri da zero al numero dato

javascript.html.markdown

@@ -600,10 +600,6 @@ of the language.
 [Eloquent Javascript][8] by Marijn Haverbeke is an excellent JS book/ebook with
 attached terminal
 
-[Eloquent Javascript - The Annotated Version][9] by Gordon Zhu is also a great
-derivative of Eloquent Javascript with extra explanations and clarifications for
-some of the more complicated examples.
-
 [Javascript: The Right Way][10] is a guide intended to introduce new developers
 to JavaScript and help experienced developers learn more about its best practices.
 
@@ -624,6 +620,5 @@ Mozilla Developer Network.
 [6]: http://www.amazon.com/gp/product/0596805527/
 [7]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/A_re-introduction_to_JavaScript
 [8]: http://eloquentjavascript.net/
-[9]: http://watchandcode.com/courses/eloquent-javascript-the-annotated-version
 [10]: http://jstherightway.org/
 [11]: https://javascript.info/

julia.html.markdown

@@ -2,17 +2,17 @@
 language: Julia
 contributors:
     - ["Leah Hanson", "http://leahhanson.us"]
-    - ["Pranit Bauva", "http://github.com/pranitbauva1997"]
+    - ["Pranit Bauva", "https://github.com/pranitbauva1997"]
-    - ["Daniel YC Lin", "http://github.com/dlintw"]
+    - ["Daniel YC Lin", "https://github.com/dlintw"]
 filename: learnjulia.jl
 ---
 
 Julia is a new homoiconic functional language focused on technical computing.
 While having the full power of homoiconic macros, first-class functions, and low-level control, Julia is as easy to learn and use as Python.
 
-This is based on Julia 0.6.4
+This is based on Julia 1.0.0
 
-```ruby
+```julia
 
 # Single line comments start with a hash (pound) symbol.
 #= Multiline comments can be written
@@ -27,38 +27,38 @@ This is based on Julia 0.6.4
 # Everything in Julia is an expression.
 
 # There are several basic types of numbers.
-3 # => 3 (Int64)
+3  # => 3 (Int64)
-3.2 # => 3.2 (Float64)
+3.2  # => 3.2 (Float64)
-2 + 1im # => 2 + 1im (Complex{Int64})
+2 + 1im  # => 2 + 1im (Complex{Int64})
-2//3 # => 2//3 (Rational{Int64})
+2 // 3  # => 2 // 3 (Rational{Int64})
 
 # All of the normal infix operators are available.
-1 + 1 # => 2
+1 + 1      # => 2
-8 - 1 # => 7
+8 - 1      # => 7
-10 * 2 # => 20
+10 * 2     # => 20
-35 / 5 # => 7.0
+35 / 5     # => 7.0
-5 / 2 # => 2.5 # dividing an Int by an Int always results in a Float
+5 / 2      # => 2.5  # dividing integers always results in a Float64
-div(5, 2) # => 2 # for a truncated result, use div
+div(5, 2)  # => 2    # for a truncated result, use div
-5 \ 35 # => 7.0
+5 \ 35     # => 7.0
-2 ^ 2 # => 4 # power, not bitwise xor
+2^2        # => 4    # power, not bitwise xor
-12 % 10 # => 2
+12 % 10    # => 2
 
 # Enforce precedence with parentheses
-(1 + 3) * 2 # => 8
+(1 + 3) * 2  # => 8
 
 # Bitwise Operators
-~2 # => -3   # bitwise not
+~2         # => -3 # bitwise not
-3 & 5 # => 1 # bitwise and
+3 & 5      # => 1  # bitwise and
-2 | 4 # => 6 # bitwise or
+2 | 4      # => 6  # bitwise or
-xor(2, 4) # => 6 # bitwise xor
+xor(2, 4)  # => 6  # bitwise xor
-2 >>> 1 # => 1 # logical shift right
+2 >>> 1    # => 1  # logical shift right
-2 >> 1  # => 1 # arithmetic shift right
+2 >> 1     # => 1  # arithmetic shift right
-2 << 1  # => 4 # logical/arithmetic shift left
+2 << 1     # => 4  # logical/arithmetic shift left
 
-# You can use the bits function to see the binary representation of a number.
+# Use the bitstring function to see the binary representation of a number.
-bits(12345)
+bitstring(12345)
 # => "0000000000000000000000000000000000000000000000000011000000111001"
-bits(12345.0)
+bitstring(12345.0)
 # => "0100000011001000000111001000000000000000000000000000000000000000"
 
 # Boolean values are primitives
@@ -66,48 +66,38 @@ true
 false
 
 # Boolean operators
-!true # => false
+!true   # => false
-!false # => true
+!false  # => true
-1 == 1 # => true
+1 == 1  # => true
-2 == 1 # => false
+2 == 1  # => false
-1 != 1 # => false
+1 != 1  # => false
-2 != 1 # => true
+2 != 1  # => true
-1 < 10 # => true
+1 < 10  # => true
-1 > 10 # => false
+1 > 10  # => false
-2 <= 2 # => true
+2 <= 2  # => true
-2 >= 2 # => true
+2 >= 2  # => true
 # Comparisons can be chained
-1 < 2 < 3 # => true
+1 < 2 < 3  # => true
-2 < 3 < 2 # => false
+2 < 3 < 2  # => false
 
 # Strings are created with "
-try
 "This is a string."
-catch ; end
-
-# Julia has several types of strings, including ASCIIString and UTF8String.
-# More on this in the Types section.
 
 # Character literals are written with '
-try
 'a'
-catch ; end
 
-# Some strings can be indexed like an array of characters
+# Strings are UTF8 encoded. Only if they contain only ASCII characters can
-try
+# they be safely indexed.
-"This is a string"[1] # => 'T' # Julia indexes from 1
+ascii("This is a string")[1]  # => 'T' # Julia indexes from 1
-catch ; end
+# Otherwise, iterating over strings is recommended (map, for loops, etc).
-# However, this is will not work well for UTF8 strings,
-# so iterating over strings is recommended (map, for loops, etc).
 
 # $ can be used for string interpolation:
-try
 "2 + 2 = $(2 + 2)" # => "2 + 2 = 4"
-catch ; end
 # You can put any Julia expression inside the parentheses.
 
-# Another way to format strings is the printf macro.
+# Another way to format strings is the printf macro from the stdlib Printf.
-@printf "%d is less than %f" 4.5 5.3 # 4 is less than 5.300000
+using Printf
+@printf "%d is less than %f\n" 4.5 5.3  # => 5 is less than 5.300000
 
 # Printing is easy
 println("I'm Julia. Nice to meet you!")
@@ -115,29 +105,29 @@ println("I'm Julia. Nice to meet you!")
 # String can be compared lexicographically
 "good" > "bye" # => true
 "good" == "good" # => true
-"1 + 2 = 3" == "1 + 2 = $(1+2)" # => true
+"1 + 2 = 3" == "1 + 2 = $(1 + 2)" # => true
 
 ####################################################
 ## 2. Variables and Collections
 ####################################################
 
 # You don't declare variables before assigning to them.
-some_var = 5 # => 5
+some_var = 5  # => 5
-some_var # => 5
+some_var  # => 5
 
 # Accessing a previously unassigned variable is an error
 try
-    some_other_var # => ERROR: some_other_var not defined
+    some_other_var  # => ERROR: UndefVarError: some_other_var not defined
 catch e
     println(e)
 end
 
 # Variable names start with a letter or underscore.
 # After that, you can use letters, digits, underscores, and exclamation points.
-SomeOtherVar123! = 6 # => 6
+SomeOtherVar123! = 6  # => 6
 
 # You can also use certain unicode characters
-☃ = 8 # => 8
+☃ = 8  # => 8
 # These are especially handy for mathematical notation
 2 * π # => 6.283185307179586
 
@@ -156,165 +146,168 @@ SomeOtherVar123! = 6 # => 6
 #   functions are sometimes called mutating functions or in-place functions.
 
 # Arrays store a sequence of values indexed by integers 1 through n:
-a = Int64[] # => 0-element Int64 Array
+a = Int64[]  # => 0-element Int64 Array
 
 # 1-dimensional array literals can be written with comma-separated values.
-b = [4, 5, 6] # => 3-element Int64 Array: [4, 5, 6]
+b = [4, 5, 6]  # => 3-element Int64 Array: [4, 5, 6]
-b = [4; 5; 6] # => 3-element Int64 Array: [4, 5, 6]
+b = [4; 5; 6]  # => 3-element Int64 Array: [4, 5, 6]
-b[1] # => 4
+b[1]  # => 4
-b[end] # => 6
+b[end]  # => 6
 
 # 2-dimensional arrays use space-separated values and semicolon-separated rows.
-matrix = [1 2; 3 4] # => 2x2 Int64 Array: [1 2; 3 4]
+matrix = [1 2; 3 4]  # => 2x2 Int64 Array: [1 2; 3 4]
 
-# Arrays of a particular Type
+# Arrays of a particular type
-b = Int8[4, 5, 6] # => 3-element Int8 Array: [4, 5, 6]
+b = Int8[4, 5, 6]  # => 3-element Int8 Array: [4, 5, 6]
 
 # Add stuff to the end of a list with push! and append!
-push!(a,1)     # => [1]
+push!(a, 1)    # => [1]
-push!(a,2)     # => [1,2]
+push!(a, 2)    # => [1,2]
-push!(a,4)     # => [1,2,4]
+push!(a, 4)    # => [1,2,4]
-push!(a,3)     # => [1,2,4,3]
+push!(a, 3)    # => [1,2,4,3]
-append!(a,b) # => [1,2,4,3,4,5,6]
+append!(a, b)  # => [1,2,4,3,4,5,6]
 
 # Remove from the end with pop
-pop!(b)        # => 6 and b is now [4,5]
+pop!(b)  # => 6 and b is now [4,5]
 
 # Let's put it back
-push!(b,6)   # b is now [4,5,6] again.
+push!(b, 6)  # b is now [4,5,6] again.
 
-a[1] # => 1 # remember that Julia indexes from 1, not 0!
+a[1]  # => 1  # remember that Julia indexes from 1, not 0!
 
 # end is a shorthand for the last index. It can be used in any
 # indexing expression
-a[end] # => 6
+a[end]  # => 6
 
-# we also have shift and unshift
+# we also have popfirst! and pushfirst!
-shift!(a) # => 1 and a is now [2,4,3,4,5,6]
+popfirst!(a)  # => 1 and a is now [2,4,3,4,5,6]
-unshift!(a,7) # => [7,2,4,3,4,5,6]
+pushfirst!(a, 7)  # => [7,2,4,3,4,5,6]
 
 # Function names that end in exclamations points indicate that they modify
 # their argument.
-arr = [5,4,6] # => 3-element Int64 Array: [5,4,6]
+arr = [5,4,6]  # => 3-element Int64 Array: [5,4,6]
-sort(arr) # => [4,5,6]; arr is still [5,4,6]
+sort(arr)  # => [4,5,6]; arr is still [5,4,6]
-sort!(arr) # => [4,5,6]; arr is now [4,5,6]
+sort!(arr)  # => [4,5,6]; arr is now [4,5,6]
 
 # Looking out of bounds is a BoundsError
 try
-    a[0] # => ERROR: BoundsError() in getindex at array.jl:270
+    a[0]
-    a[end+1] # => ERROR: BoundsError() in getindex at array.jl:270
+    # => BoundsError: attempt to access 7-element Array{Int64,1} at index [0]
+    a[end + 1]
+    # => BoundsError: attempt to access 7-element Array{Int64,1} at index [8]
 catch e
     println(e)
 end
 
 # Errors list the line and file they came from, even if it's in the standard
-# library. If you built Julia from source, you can look in the folder base
+# library. You can look in the folder share/julia inside the julia folder to
-# inside the julia folder to find these files.
+# find these files.
 
 # You can initialize arrays from ranges
-a = [1:5;] # => 5-element Int64 Array: [1,2,3,4,5]
+a = [1:5;]  # => 5-element Int64 Array: [1,2,3,4,5]
 
 # You can look at ranges with slice syntax.
-a[1:3] # => [1, 2, 3]
+a[1:3]  # => [1, 2, 3]
-a[2:end] # => [2, 3, 4, 5]
+a[2:end]  # => [2, 3, 4, 5]
 
 # Remove elements from an array by index with splice!
 arr = [3,4,5]
-splice!(arr,2) # => 4 ; arr is now [3,5]
+splice!(arr, 2)  # => 4 ; arr is now [3,5]
 
 # Concatenate lists with append!
 b = [1,2,3]
-append!(a,b) # Now a is [1, 2, 3, 4, 5, 1, 2, 3]
+append!(a, b)  # Now a is [1, 2, 3, 4, 5, 1, 2, 3]
 
 # Check for existence in a list with in
-in(1, a) # => true
+in(1, a)  # => true
 
 # Examine the length with length
-length(a) # => 8
+length(a)  # => 8
 
 # Tuples are immutable.
-tup = (1, 2, 3) # => (1,2,3) # an (Int64,Int64,Int64) tuple.
+tup = (1, 2, 3)  # => (1,2,3)  # an (Int64,Int64,Int64) tuple.
-tup[1] # => 1
+tup[1]  # => 1
-try:
+try
-    tup[1] = 3 # => ERROR: no method setindex!((Int64,Int64,Int64),Int64,Int64)
+    tup[1] = 3  # => ERROR: no method setindex!((Int64,Int64,Int64),Int64,Int64)
 catch e
     println(e)
 end
 
-# Many list functions also work on tuples
+# Many array functions also work on tuples
-length(tup) # => 3
+length(tup)  # => 3
-tup[1:2] # => (1,2)
+tup[1:2]  # => (1,2)
-in(2, tup) # => true
+in(2, tup)  # => true
 
 # You can unpack tuples into variables
-a, b, c = (1, 2, 3) # => (1,2,3)  # a is now 1, b is now 2 and c is now 3
+a, b, c = (1, 2, 3)  # => (1,2,3)  # a is now 1, b is now 2 and c is now 3
 
 # Tuples are created even if you leave out the parentheses
-d, e, f = 4, 5, 6 # => (4,5,6)
+d, e, f = 4, 5, 6  # => (4,5,6)
 
 # A 1-element tuple is distinct from the value it contains
-(1,) == 1 # => false
+(1,) == 1  # => false
-(1) == 1 # => true
+(1) == 1  # => true
 
 # Look how easy it is to swap two values
-e, d = d, e  # => (5,4) # d is now 5 and e is now 4
+e, d = d, e  # => (5,4)  # d is now 5 and e is now 4
 
 
 # Dictionaries store mappings
-empty_dict = Dict() # => Dict{Any,Any}()
+empty_dict = Dict()  # => Dict{Any,Any}()
 
 # You can create a dictionary using a literal
-filled_dict = Dict("one"=> 1, "two"=> 2, "three"=> 3)
+filled_dict = Dict("one" => 1, "two" => 2, "three" => 3)
-# => Dict{ASCIIString,Int64}
+# => Dict{String,Int64}
 
 # Look up values with []
-filled_dict["one"] # => 1
+filled_dict["one"]  # => 1
 
 # Get all keys
 keys(filled_dict)
-# => KeyIterator{Dict{ASCIIString,Int64}}(["three"=>3,"one"=>1,"two"=>2])
+# => Base.KeySet for a Dict{String,Int64} with 3 entries. Keys:
+# "two", "one", "three"
 # Note - dictionary keys are not sorted or in the order you inserted them.
 
 # Get all values
 values(filled_dict)
-# => ValueIterator{Dict{ASCIIString,Int64}}(["three"=>3,"one"=>1,"two"=>2])
+# => Base.ValueIterator{Dict{String,Int64}} with 3 entries. Values: 2, 1, 3
 # Note - Same as above regarding key ordering.
 
 # Check for existence of keys in a dictionary with in, haskey
-in(("one" => 1), filled_dict) # => true
+in(("one" => 1), filled_dict)  # => true
-in(("two" => 3), filled_dict) # => false
+in(("two" => 3), filled_dict)  # => false
-haskey(filled_dict, "one") # => true
+haskey(filled_dict, "one")     # => true
-haskey(filled_dict, 1) # => false
+haskey(filled_dict, 1)         # => false
 
 # Trying to look up a non-existent key will raise an error
 try
-    filled_dict["four"] # => ERROR: key not found: four in getindex at dict.jl:489
+    filled_dict["four"]  # => KeyError: key "four" not found
 catch e
     println(e)
 end
 
 # Use the get method to avoid that error by providing a default value
-# get(dictionary,key,default_value)
+# get(dictionary, key, default_value)
-get(filled_dict,"one",4) # => 1
+get(filled_dict, "one", 4)   # => 1
-get(filled_dict,"four",4) # => 4
+get(filled_dict, "four", 4)  # => 4
 
 # Use Sets to represent collections of unordered, unique values
-empty_set = Set() # => Set{Any}()
+empty_set = Set()  # => Set{Any}()
 # Initialize a set with values
-filled_set = Set([1,2,2,3,4]) # => Set{Int64}(1,2,3,4)
+filled_set = Set([1, 2, 2, 3, 4])  # => Set([4, 2, 3, 1])
 
 # Add more values to a set
-push!(filled_set,5) # => Set{Int64}(5,4,2,3,1)
+push!(filled_set, 5)  # => Set([4, 2, 3, 5, 1])
 
 # Check if the values are in the set
-in(2, filled_set) # => true
+in(2, filled_set)  # => true
-in(10, filled_set) # => false
+in(10, filled_set)  # => false
 
 # There are functions for set intersection, union, and difference.
-other_set = Set([3, 4, 5, 6]) # => Set{Int64}(6,4,5,3)
+other_set = Set([3, 4, 5, 6])          # => Set([4, 3, 5, 6])
-intersect(filled_set, other_set) # => Set{Int64}(3,4,5)
+intersect(filled_set, other_set)       # => Set([4, 3, 5])
-union(filled_set, other_set) # => Set{Int64}(1,2,3,4,5,6)
+union(filled_set, other_set)           # => Set([4, 2, 3, 5, 6, 1])
-setdiff(Set([1,2,3,4]),Set([2,3,5])) # => Set{Int64}(1,4)
+setdiff(Set([1,2,3,4]), Set([2,3,5]))  # => Set([4, 1])
 
 
 ####################################################
@@ -337,7 +330,7 @@ end
 
 # For loops iterate over iterables.
 # Iterable types include Range, Array, Set, Dict, and AbstractString.
-for animal=["dog", "cat", "mouse"]
+for animal = ["dog", "cat", "mouse"]
     println("$animal is a mammal")
     # You can use $ to interpolate variables or expression into strings
 end
@@ -355,15 +348,16 @@ end
 #    cat is a mammal
 #    mouse is a mammal
 
-for a in Dict("dog"=>"mammal","cat"=>"mammal","mouse"=>"mammal")
+for pair in Dict("dog" => "mammal", "cat" => "mammal", "mouse" => "mammal")
-    println("$(a[1]) is a $(a[2])")
+    from, to = pair
+    println("$from is a $to")
 end
 # prints:
 #    dog is a mammal
 #    cat is a mammal
 #    mouse is a mammal
 
-for (k,v) in Dict("dog"=>"mammal","cat"=>"mammal","mouse"=>"mammal")
+for (k, v) in Dict("dog" => "mammal", "cat" => "mammal", "mouse" => "mammal")
     println("$k is a $v")
 end
 # prints:
@@ -372,10 +366,11 @@ end
 #    mouse is a mammal
 
 # While loops loop while a condition is true
-x = 0
+let x = 0
-while x < 4
+    while x < 4
-    println(x)
+        println(x)
-    x += 1  # Shorthand for x = x + 1
+        x += 1  # Shorthand for x = x + 1
+    end
 end
 # prints:
 #   0
@@ -385,9 +380,9 @@ end
 
 # Handle exceptions with a try/catch block
 try
-   error("help")
+    error("help")
 catch e
-   println("caught it $e")
+    println("caught it $e")
 end
 # => caught it ErrorException("help")
 
@@ -407,15 +402,15 @@ function add(x, y)
     x + y
 end
 
-add(5, 6) # => 11 after printing out "x is 5 and y is 6"
+add(5, 6)  # => 11 after printing out "x is 5 and y is 6"
 
 # Compact assignment of functions
-f_add(x, y) = x + y # => "f (generic function with 1 method)"
+f_add(x, y) = x + y  # => "f (generic function with 1 method)"
-f_add(3, 4) # => 7
+f_add(3, 4)  # => 7
 
 # Function can also return multiple values as tuple
 fn(x, y) = x + y, x - y
-fn(3, 4) # => (7, -1)
+fn(3, 4)  # => (7, -1)
 
 # You can define functions that take a variable number of
 # positional arguments
@@ -425,41 +420,41 @@ function varargs(args...)
 end
 # => varargs (generic function with 1 method)
 
-varargs(1,2,3) # => (1,2,3)
+varargs(1, 2, 3)  # => (1,2,3)
 
 # The ... is called a splat.
 # We just used it in a function definition.
 # It can also be used in a function call,
 # where it will splat an Array or Tuple's contents into the argument list.
-add([5,6]...) # this is equivalent to add(5,6)
+add([5,6]...)  # this is equivalent to add(5,6)
 
-x = (5,6)     # => (5,6)
+x = (5, 6)  # => (5,6)
-add(x...)     # this is equivalent to add(5,6)
+add(x...)  # this is equivalent to add(5,6)
 
 
 # You can define functions with optional positional arguments
-function defaults(a,b,x=5,y=6)
+function defaults(a, b, x=5, y=6)
     return "$a $b and $x $y"
 end
 
-defaults('h','g') # => "h g and 5 6"
+defaults('h', 'g')  # => "h g and 5 6"
-defaults('h','g','j') # => "h g and j 6"
+defaults('h', 'g', 'j')  # => "h g and j 6"
-defaults('h','g','j','k') # => "h g and j k"
+defaults('h', 'g', 'j', 'k')  # => "h g and j k"
 try
-    defaults('h') # => ERROR: no method defaults(Char,)
+    defaults('h')  # => ERROR: no method defaults(Char,)
-    defaults() # => ERROR: no methods defaults()
+    defaults()  # => ERROR: no methods defaults()
 catch e
     println(e)
 end
 
 # You can define functions that take keyword arguments
-function keyword_args(;k1=4,name2="hello") # note the ;
+function keyword_args(;k1=4, name2="hello")  # note the ;
-    return Dict("k1"=>k1,"name2"=>name2)
+    return Dict("k1" => k1, "name2" => name2)
 end
 
-keyword_args(name2="ness") # => ["name2"=>"ness","k1"=>4]
+keyword_args(name2="ness")  # => ["name2"=>"ness","k1"=>4]
-keyword_args(k1="mine") # => ["k1"=>"mine","name2"=>"hello"]
+keyword_args(k1="mine")  # => ["k1"=>"mine","name2"=>"hello"]
-keyword_args() # => ["name2"=>"hello","k1"=>4]
+keyword_args()  # => ["name2"=>"hello","k1"=>4]
 
 # You can combine all kinds of arguments in the same function
 function all_the_args(normal_arg, optional_positional_arg=2; keyword_arg="foo")
@@ -483,7 +478,7 @@ function create_adder(x)
 end
 
 # This is "stabby lambda syntax" for creating anonymous functions
-(x -> x > 2)(3) # => true
+(x -> x > 2)(3)  # => true
 
 # This function is identical to create_adder implementation above.
 function create_adder(x)
@@ -499,16 +494,17 @@ function create_adder(x)
 end
 
 add_10 = create_adder(10)
-add_10(3) # => 13
+add_10(3)  # => 13
 
 
 # There are built-in higher order functions
-map(add_10, [1,2,3]) # => [11, 12, 13]
+map(add_10, [1,2,3])  # => [11, 12, 13]
-filter(x -> x > 5, [3, 4, 5, 6, 7]) # => [6, 7]
+filter(x -> x > 5, [3, 4, 5, 6, 7])  # => [6, 7]
 
-# We can use list comprehensions for nicer maps
+# We can use list comprehensions
-[add_10(i) for i=[1, 2, 3]] # => [11, 12, 13]
+[add_10(i) for i = [1, 2, 3]] # => [11, 12, 13]
 [add_10(i) for i in [1, 2, 3]] # => [11, 12, 13]
+[x for x in [3, 4, 5, 6, 7] if x > 5] # => [6, 7]
 
 ####################################################
 ## 5. Types
@@ -517,11 +513,11 @@ filter(x -> x > 5, [3, 4, 5, 6, 7]) # => [6, 7]
 # Julia has a type system.
 # Every value has a type; variables do not have types themselves.
 # You can use the `typeof` function to get the type of a value.
-typeof(5) # => Int64
+typeof(5)  # => Int64
 
 # Types are first-class values
-typeof(Int64) # => DataType
+typeof(Int64)  # => DataType
-typeof(DataType) # => DataType
+typeof(DataType)  # => DataType
 # DataType is the type that represents types, including itself.
 
 # Types are used for documentation, optimizations, and dispatch.
@@ -529,78 +525,77 @@ typeof(DataType) # => DataType
 
 # Users can define types
 # They are like records or structs in other languages.
-# New types are defined using the `type` keyword.
+# New types are defined using the `struct` keyword.
 
-# type Name
+# struct Name
 #   field::OptionalType
 #   ...
 # end
-type Tiger
+struct Tiger
-  taillength::Float64
+    taillength::Float64
-  coatcolor # not including a type annotation is the same as `::Any`
+    coatcolor  # not including a type annotation is the same as `::Any`
 end
 
 # The default constructor's arguments are the properties
 # of the type, in the order they are listed in the definition
-tigger = Tiger(3.5,"orange") # => Tiger(3.5,"orange")
+tigger = Tiger(3.5, "orange")  # => Tiger(3.5,"orange")
 
 # The type doubles as the constructor function for values of that type
-sherekhan = typeof(tigger)(5.6,"fire") # => Tiger(5.6,"fire")
+sherekhan = typeof(tigger)(5.6, "fire")  # => Tiger(5.6,"fire")
 
 # These struct-style types are called concrete types
 # They can be instantiated, but cannot have subtypes.
 # The other kind of types is abstract types.
 
 # abstract Name
-abstract type Cat end # just a name and point in the type hierarchy
+abstract type Cat end  # just a name and point in the type hierarchy
 
 # Abstract types cannot be instantiated, but can have subtypes.
+using InteractiveUtils  # defines the subtype and supertype function
 # For example, Number is an abstract type
-subtypes(Number) # => 2-element Array{Any,1}:
+subtypes(Number)  # => 2-element Array{Any,1}:
                  #     Complex{T<:Real}
                  #     Real
-subtypes(Cat) # => 0-element Array{Any,1}
+subtypes(Cat)  # => 0-element Array{Any,1}
 
 # AbstractString, as the name implies, is also an abstract type
-subtypes(AbstractString)        # 6-element Array{Union{DataType, UnionAll},1}:
+subtypes(AbstractString)  # 4-element Array{Any,1}:
-				# Base.SubstitutionString
+                            #  String
-				# Base.Test.GenericString
+                            #  SubString
-				# DirectIndexString      
+                            #  SubstitutionString
-				# RevString              
+                            #  Test.GenericString
-				# String                 
-				# SubString
 
 # Every type has a super type; use the `supertype` function to get it.
-typeof(5) # => Int64
+typeof(5)  # => Int64
-supertype(Int64) # => Signed
+supertype(Int64)  # => Signed
-supertype(Signed) # => Integer
+supertype(Signed)  # => Integer
-supertype(Integer) # => Real
+supertype(Integer)  # => Real
-supertype(Real) # => Number
+supertype(Real)  # => Number
-supertype(Number) # => Any
+supertype(Number)  # => Any
-supertype(supertype(Signed)) # => Real
+supertype(supertype(Signed))  # => Real
-supertype(Any) # => Any
+supertype(Any)  # => Any
 # All of these type, except for Int64, are abstract.
-typeof("fire") # => String
+typeof("fire")  # => String
-supertype(String) # => AbstractString
+supertype(String)  # => AbstractString
 # Likewise here with String
-supertype(DirectIndexString) # => AbstractString
+supertype(SubString)  # => AbstractString
 
 # <: is the subtyping operator
-type Lion <: Cat # Lion is a subtype of Cat
+struct Lion <: Cat  # Lion is a subtype of Cat
-  mane_color
+    mane_color
-  roar::AbstractString
+    roar::AbstractString
 end
 
 # You can define more constructors for your type
 # Just define a function of the same name as the type
 # and call an existing constructor to get a value of the correct type
-Lion(roar::AbstractString) = Lion("green",roar)
+Lion(roar::AbstractString) = Lion("green", roar)
 # This is an outer constructor because it's outside the type definition
 
-type Panther <: Cat # Panther is also a subtype of Cat
+struct Panther <: Cat  # Panther is also a subtype of Cat
-  eye_color
+    eye_color
-  Panther() = new("green")
+    Panther() = new("green")
-  # Panthers will only have this constructor, and no default constructor.
+    # Panthers will only have this constructor, and no default constructor.
 end
 # Using inner constructors, like Panther does, gives you control
 # over how values of the type can be created.
@@ -618,35 +613,35 @@ end
 
 # Definitions for Lion, Panther, Tiger
 function meow(animal::Lion)
-  animal.roar # access type properties using dot notation
+    animal.roar  # access type properties using dot notation
 end
 
 function meow(animal::Panther)
-  "grrr"
+    "grrr"
 end
 
 function meow(animal::Tiger)
-  "rawwwr"
+    "rawwwr"
 end
 
 # Testing the meow function
-meow(tigger) # => "rawwr"
+meow(tigger)  # => "rawwr"
-meow(Lion("brown","ROAAR")) # => "ROAAR"
+meow(Lion("brown", "ROAAR"))  # => "ROAAR"
-meow(Panther()) # => "grrr"
+meow(Panther())  # => "grrr"
 
 # Review the local type hierarchy
-issubtype(Tiger,Cat) # => false
+Tiger <: Cat # => false
-issubtype(Lion,Cat) # => true
+Lion <: Cat # => true
-issubtype(Panther,Cat) # => true
+Panther <: Cat # => true
 
 # Defining a function that takes Cats
 function pet_cat(cat::Cat)
-  println("The cat says $(meow(cat))")
+    println("The cat says $(meow(cat))")
 end
 
-pet_cat(Lion("42")) # => prints "The cat says 42"
+pet_cat(Lion("42"))  # => prints "The cat says 42"
 try
-    pet_cat(tigger) # => ERROR: no method pet_cat(Tiger,)
+    pet_cat(tigger)  # => ERROR: no method pet_cat(Tiger,)
 catch e
     println(e)
 end
@@ -656,129 +651,132 @@ end
 # In Julia, all of the argument types contribute to selecting the best method.
 
 # Let's define a function with more arguments, so we can see the difference
-function fight(t::Tiger,c::Cat)
+function fight(t::Tiger, c::Cat)
-  println("The $(t.coatcolor) tiger wins!")
+    println("The $(t.coatcolor) tiger wins!")
 end
 # => fight (generic function with 1 method)
 
-fight(tigger,Panther()) # => prints The orange tiger wins!
+fight(tigger, Panther())  # => prints The orange tiger wins!
-fight(tigger,Lion("ROAR")) # => prints The orange tiger wins!
+fight(tigger, Lion("ROAR"))  # => prints The orange tiger wins!
 
 # Let's change the behavior when the Cat is specifically a Lion
-fight(t::Tiger,l::Lion) = println("The $(l.mane_color)-maned lion wins!")
+fight(t::Tiger, l::Lion) = println("The $(l.mane_color)-maned lion wins!")
 # => fight (generic function with 2 methods)
 
-fight(tigger,Panther()) # => prints The orange tiger wins!
+fight(tigger, Panther())  # => prints The orange tiger wins!
-fight(tigger,Lion("ROAR")) # => prints The green-maned lion wins!
+fight(tigger, Lion("ROAR"))  # => prints The green-maned lion wins!
 
 # We don't need a Tiger in order to fight
-fight(l::Lion,c::Cat) = println("The victorious cat says $(meow(c))")
+fight(l::Lion, c::Cat) = println("The victorious cat says $(meow(c))")
 # => fight (generic function with 3 methods)
 
-fight(Lion("balooga!"),Panther()) # => prints The victorious cat says grrr
+fight(Lion("balooga!"), Panther())  # => prints The victorious cat says grrr
 try
-  fight(Panther(),Lion("RAWR"))
+    fight(Panther(), Lion("RAWR"))
 catch e
-  println(e) 
+    println(e)
-  # => MethodError(fight, (Panther("green"), Lion("green", "RAWR")), 0x000000000000557b)
+    # => MethodError(fight, (Panther("green"), Lion("green", "RAWR")),
+    #                0x000000000000557b)
 end
 
 # Also let the cat go first
-fight(c::Cat,l::Lion) = println("The cat beats the Lion")
+fight(c::Cat, l::Lion) = println("The cat beats the Lion")
 
 # This warning is because it's unclear which fight will be called in:
 try
-  fight(Lion("RAR"),Lion("brown","rarrr")) # => prints The victorious cat says rarrr
+    fight(Lion("RAR"), Lion("brown", "rarrr"))
+    # => prints The victorious cat says rarrr
 catch e
-  println(e)
+    println(e)
-  # => MethodError(fight, (Lion("green", "RAR"), Lion("brown", "rarrr")), 0x000000000000557c)
+  # => MethodError(fight, (Lion("green", "RAR"), Lion("brown", "rarrr")),
+  #                0x000000000000557c)
 end
 # The result may be different in other versions of Julia
 
-fight(l::Lion,l2::Lion) = println("The lions come to a tie")
+fight(l::Lion, l2::Lion) = println("The lions come to a tie")
-fight(Lion("RAR"),Lion("brown","rarrr")) # => prints The lions come to a tie
+fight(Lion("RAR"), Lion("brown", "rarrr"))  # => prints The lions come to a tie
 
 
 # Under the hood
 # You can take a look at the llvm  and the assembly code generated.
 
-square_area(l) = l * l      # square_area (generic function with 1 method)
+square_area(l) = l * l  # square_area (generic function with 1 method)
 
-square_area(5) #25
+square_area(5)  # => 25
 
 # What happens when we feed square_area an integer?
 code_native(square_area, (Int32,))
-	#	    .section    __TEXT,__text,regular,pure_instructions
+    #        .section    __TEXT,__text,regular,pure_instructions
-	#	Filename: none
+    #    Filename: none
-	#	Source line: 1              # Prologue
+    #    Source line: 1              # Prologue
-	#	    push    RBP
+    #        push    RBP
-	#	    mov RBP, RSP
+    #        mov RBP, RSP
-	#	Source line: 1
+    #    Source line: 1
-	#	    movsxd  RAX, EDI        # Fetch l from memory?
+    #        movsxd  RAX, EDI        # Fetch l from memory?
-	#	    imul    RAX, RAX        # Square l and store the result in RAX
+    #        imul    RAX, RAX        # Square l and store the result in RAX
-	#	    pop RBP                 # Restore old base pointer
+    #        pop RBP                 # Restore old base pointer
-	#	    ret                     # Result will still be in RAX
+    #        ret                     # Result will still be in RAX
 
 code_native(square_area, (Float32,))
-	#	    .section    __TEXT,__text,regular,pure_instructions
+    #        .section    __TEXT,__text,regular,pure_instructions
-	#	Filename: none
+    #    Filename: none
-	#	Source line: 1
+    #    Source line: 1
-	#	    push    RBP
+    #        push    RBP
-	#	    mov RBP, RSP
+    #        mov RBP, RSP
-	#	Source line: 1
+    #    Source line: 1
-	#	    vmulss  XMM0, XMM0, XMM0  # Scalar single precision multiply (AVX)
+    #        vmulss  XMM0, XMM0, XMM0  # Scalar single precision multiply (AVX)
-	#	    pop RBP
+    #        pop RBP
-	#	    ret
+    #        ret
 
 code_native(square_area, (Float64,))
-	#	    .section    __TEXT,__text,regular,pure_instructions
+    #        .section    __TEXT,__text,regular,pure_instructions
-	#	Filename: none
+    #    Filename: none
-	#	Source line: 1
+    #    Source line: 1
-	#	    push    RBP
+    #        push    RBP
-	#	    mov RBP, RSP
+    #        mov RBP, RSP
-	#	Source line: 1
+    #    Source line: 1
-	#	    vmulsd  XMM0, XMM0, XMM0 # Scalar double precision multiply (AVX)
+    #        vmulsd  XMM0, XMM0, XMM0  # Scalar double precision multiply (AVX)
-	#	    pop RBP
+    #        pop RBP
-	#	    ret
+    #        ret
-	#
+    #
 # Note that julia will use floating point instructions if any of the
 # arguments are floats.
 # Let's calculate the area of a circle
 circle_area(r) = pi * r * r     # circle_area (generic function with 1 method)
-circle_area(5)                  # 78.53981633974483
+circle_area(5)  # 78.53981633974483
 
 code_native(circle_area, (Int32,))
-	#	    .section    __TEXT,__text,regular,pure_instructions
+    #        .section    __TEXT,__text,regular,pure_instructions
-	#	Filename: none
+    #    Filename: none
-	#	Source line: 1
+    #    Source line: 1
-	#	    push    RBP
+    #        push    RBP
-	#	    mov RBP, RSP
+    #        mov RBP, RSP
-	#	Source line: 1
+    #    Source line: 1
-	#	    vcvtsi2sd   XMM0, XMM0, EDI          # Load integer (r) from memory
+    #        vcvtsi2sd   XMM0, XMM0, EDI          # Load integer (r) from memory
-	#	    movabs  RAX, 4593140240              # Load pi
+    #        movabs  RAX, 4593140240              # Load pi
-	#	    vmulsd  XMM1, XMM0, QWORD PTR [RAX]  # pi * r
+    #        vmulsd  XMM1, XMM0, QWORD PTR [RAX]  # pi * r
-	#	    vmulsd  XMM0, XMM0, XMM1             # (pi * r) * r
+    #        vmulsd  XMM0, XMM0, XMM1             # (pi * r) * r
-	#	    pop RBP
+    #        pop RBP
-	#	    ret
+    #        ret
-	#
+    #
 
 code_native(circle_area, (Float64,))
-	#	    .section    __TEXT,__text,regular,pure_instructions
+    #        .section    __TEXT,__text,regular,pure_instructions
-	#	Filename: none
+    #    Filename: none
-	#	Source line: 1
+    #    Source line: 1
-	#	    push    RBP
+    #        push    RBP
-	#	    mov RBP, RSP
+    #        mov RBP, RSP
-	#	    movabs  RAX, 4593140496
+    #        movabs  RAX, 4593140496
-	#	Source line: 1
+    #    Source line: 1
-	#	    vmulsd  XMM1, XMM0, QWORD PTR [RAX]
+    #        vmulsd  XMM1, XMM0, QWORD PTR [RAX]
-	#	    vmulsd  XMM0, XMM1, XMM0
+    #        vmulsd  XMM0, XMM1, XMM0
-	#	    pop RBP
+    #        pop RBP
-	#	    ret
+    #        ret
-	#
+    #
 ```
 
 ## Further Reading
 
-You can get a lot more detail from [The Julia Manual](http://docs.julialang.org/en/latest/#Manual-1)
+You can get a lot more detail from the [Julia Documentation](https://docs.julialang.org/)
 
 The best place to get help with Julia is the (very friendly) [Discourse forum](https://discourse.julialang.org/).

kdb+.html.markdown

@@ -689,14 +689,14 @@ first each (1 2 3;4 5 6;7 8 9)
 
 / each-left (\:) and each-right (/:) modify a two-argument function
 / to treat one of the arguments and individual variables instead of a list
-1 2 3 +\: 1 2 3
+1 2 3 +\: 11 22 33
-/ => 2 3 4
+/ => 12 23 34
-/ => 3 4 5
+/ => 13 24 35
-/ => 4 5 6
+/ => 14 25 36
-1 2 3 +/: 1 2 3
+1 2 3 +/: 11 22 33
-/ => 2 3 4
+/ => 12 13 14
-/ => 3 4 5
+/ => 23 24 25
-/ => 4 5 6
+/ => 34 35 36
 
 / The true alternatives to loops in q are the adverbs scan (\) and over (/)
 / their behaviour differs based on the number of arguments the function they

ko-kr/markdown-kr.html.markdown

@@ -25,7 +25,7 @@ lang: ko-kr
 
 ## HTML 요소
 HTML은 마크다운의 수퍼셋입니다. 모든 HTML 파일은 유효한 마크다운이라는 것입니다.
-```markdown
+```md
 <!--따라서 주석과 같은 HTML 요소들을 마크다운에 사용할 수 있으며, 마크다운 파서에 영향을
 받지 않을 것입니다. 하지만 마크다운 파일에서 HTML 요소를 만든다면 그 요소의 안에서는
 마크다운 문법을 사용할 수 없습니다.-->

markdown.html.markdown

@@ -197,7 +197,7 @@ inside your code
     end
 ```
 
-Inline code can be created using the backtick character `
+Inline code can be created using the backtick character `` ` ``
 
 ```md
 John didn't even know what the `go_to()` function did!

mips.html.markdown

@@ -0,0 +1,366 @@
+---
+language: "MIPS Assembly"
+filename: MIPS.asm
+contributors:
+  - ["Stanley Lim", "https://github.com/Spiderpig86"]
+---
+
+The MIPS (Microprocessor without Interlocked Pipeline Stages) Assembly language
+is designed to work with the MIPS microprocessor paradigm designed by J. L. 
+Hennessy in 1981. These RISC processors are used in embedded systems such as 
+gateways and routers.
+
+[Read More](https://en.wikipedia.org/wiki/MIPS_architecture)
+
+```assembly
+# Comments are denoted with a '#'
+
+# Everything that occurs after a '#' will be ignored by the assembler's lexer.
+
+# Programs typically contain a .data and .text sections
+
+.data # Section where data is stored in memory (allocated in RAM), similar to
+      # variables in higher level languages
+
+  # Declarations follow a ( label: .type value(s) ) form of declaration
+  hello_world: .asciiz "Hello World\n"      # Declare a null terminated string
+  num1: .word 42                            # Integers are referred to as words
+                                            # (32 bit value)
+
+  arr1: .word 1, 2, 3, 4, 5                 # Array of words
+  arr2: .byte 'a', 'b'                      # Array of chars (1 byte each)
+  buffer: .space 60                         # Allocates space in the RAM 
+                                            # (not cleared to 0)
+
+  # Datatype sizes
+  _byte: .byte 'a'                          # 1 byte
+  _halfword: .half 53                       # 2 bytes
+  _word: .word 3                            # 4 bytes
+  _float: .float 3.14                       # 4 bytes
+  _double: .double 7.0                      # 8 bytes
+
+  .align 2                                  # Memory alignment of data, where 
+                                            # number indicates byte alignment in
+                                            # powers of 2. (.align 2 represents 
+                                            # word alignment since 2^2 = 4 bytes)
+
+.text                                       # Section that contains instructions
+                                            # and program logic
+.globl _main                                # Declares an instruction label as
+                                            # global, making it accessible to
+                                            # other files
+
+  _main:                                    # MIPS programs execute instructions
+                                            # sequentially, where the code under
+                                            # this label will be executed firsts
+
+    # Let's print "hello world"
+    la $a0, hello_world                     # Load address of string stored in
+                                            # memory
+    li $v0, 4                               # Load the syscall value (indicating
+                                            # type of functionality)
+    syscall                                 # Perform the specified syscall with
+                                            # the given argument ($a0)
+
+    # Registers (used to hold data during program execution)
+    # $t0 - $t9                             # Temporary registers used for 
+                                            # intermediate calculations inside 
+                                            # subroutines (not saved across 
+                                            # function calls)
+
+    # $s0 - $s7                             # Saved registers where values are 
+                                            # saved across subroutine calls. 
+                                            # Typically saved in stack
+
+    # $a0 - $a3                             # Argument registers for passing in 
+                                            # arguments for subroutines
+    # $v0 - $v1                             # Return registers for returning 
+                                            # values to caller function
+
+    # Types of load/store instructions
+    la $t0, label                           # Copy the address of a value in
+                                            # memory specified by the label into 
+                                            # register $t0
+    lw $t0, label                           # Copy a word value from memory
+    lw $t1, 4($s0)                          # Copy a word value from an address
+                                            # stored in a register with an offset 
+                                            # of 4 bytes (addr + 4)
+    lb $t2, label                           # Copy a byte value to the lower order
+                                            # portion of the register $t2
+    lb $t2, 0($s0)                          # Copy a byte value from the source
+                                            # address in $s0 with offset 0
+    # Same idea with 'lh' for halfwords
+
+    sw $t0, label                           # Store word value into memory address 
+                                            # mapped by label
+    sw $t0, 8($s0)                          # Store word value into address 
+                                            # specified in $s0 and offset of 8 bytes
+    # Same idea using 'sb' and 'sh' for bytes and halfwords. 'sa' does not exist
+
+### Math ###
+  _math:
+    # Remember to load your values into a register
+    lw $t0, num                             # From the data section
+    li $t0, 5                               # Or from an immediate (constant)
+    li $t1, 6
+    add $t2, $t0, $t1                       # $t2 = $t0 + $t1
+    sub $t2, $t0, $t1                       # $t2 = $t0 - $t1
+    mul $t2, $t0, $t1                       # $t2 = $t0 * $t1
+    div $t2, $t0, $t1                       # $t2 = $t0 / $t1 (Might not be 
+                                            # supported in some versons of MARS)
+    div $t0, $t1                            # Performs $t0 / $t1. Get the quotient
+                                            # using 'mflo' and remainder using 'mfhi'
+
+    # Bitwise Shifting
+    sll $t0, $t0, 2                         # Bitwise shift to the left with 
+                                            # immediate (constant value) of 2
+    sllv $t0, $t1, $t2                      # Shift left by a variable amount in
+                                            # register
+    srl $t0, $t0, 5                         # Bitwise shift to the right (does 
+                                            # not sign preserve, sign-extends with 0)
+    srlv $t0, $t1, $t2                      # Shift right by a variable amount in
+                                            # a register
+    sra $t0, $t0, 7                         # Bitwise arithmetic shift to the right 
+                                            # (preserves sign)
+    srav $t0, $t1, $t2                      # Shift right by a variable amount 
+                                            # in a register
+
+    # Bitwise operators
+    and $t0, $t1, $t2                       # Bitwise AND
+    andi $t0, $t1, 0xFFF                    # Bitwise AND with immediate
+    or $t0, $t1, $t2                        # Bitwise OR
+    ori $t0, $t1, 0xFFF                     # Bitwise OR with immediate
+    xor $t0, $t1, $t2                       # Bitwise XOR
+    xori $t0, $t1, 0xFFF                    # Bitwise XOR with immediate
+    nor $t0, $t1, $t2                       # Bitwise NOR
+
+## BRANCHING ##
+  _branching:
+    # The basic format of these branching instructions typically follow <instr>
+    # <reg1> <reg2> <label> where label is the label we want to jump to if the
+    # given conditional evaluates to true
+    # Sometimes it is easier to write the conditional logic backwards, as seen
+    # in the simple if statement example below
+
+    beq $t0, $t1, reg_eq                    # Will branch to reg_eq if
+                                            # $t0 == $t1, otherwise
+                                            # execute the next line
+    bne $t0, $t1, reg_neq                   # Branches when $t0 != $t1
+    b branch_target                         # Unconditional branch, will always execute
+    beqz $t0, req_eq_zero                   # Branches when $t0 == 0
+    bnez $t0, req_neq_zero                  # Branches when $t0 != 0
+    bgt $t0, $t1, t0_gt_t1                  # Branches when $t0 > $t1
+    bge $t0, $t1, t0_gte_t1                 # Branches when $t0 >= $t1
+    bgtz $t0, t0_gt0                        # Branches when $t0 > 0
+    blt $t0, $t1, t0_gt_t1                  # Branches when $t0 < $t1
+    ble $t0, $t1, t0_gte_t1                 # Branches when $t0 <= $t1
+    bltz $t0, t0_lt0                        # Branches when $t0 < 0
+    slt $s0, $t0, $t1                       # Instruction that sends a signal when
+                                            # $t0 < $t1 with reuslt in $s0 (1 for true)
+
+    # Simple if statement
+    # if (i == j)
+    #     f = g + h;
+    #  f = f - i;
+
+    # Let $s0 = f, $s1 = g, $s2 = h, $s3 = i, $s4 = j
+    bne $s3, $s4, L1 # if (i !=j)
+    add $s0, $s1, $s2 # f = g + h
+
+    L1:
+      sub $s0, $s0, $s3 # f = f - i
+    
+    # Below is an example of finding the max of 3 numbers
+    # A direct translation in Java from MIPS logic:
+    # if (a > b)
+    #   if (a > c)
+    #     max = a;
+    #   else
+    #     max = c;
+    # else
+    #     max = b;
+    #   else
+    #     max = c;
+
+    # Let $s0 = a, $s1 = b, $s2 = c, $v0 = return register
+    ble $s0, $s1, a_LTE_b                   # if (a <= b) branch(a_LTE_b)
+    ble $s0, $s2, max_C                     # if (a > b && a <=c) branch(max_C)
+    move $v0, $s1                           # else [a > b && a > c] max = a
+    j done                                  # Jump to the end of the program
+
+    a_LTE_b:                                # Label for when a <= b
+      ble $s1, $s2, max_C                   # if (a <= b && b <= c) branch(max_C)
+      move $v0, $s1                         # if (a <= b && b > c) max = b
+      j done                                # Jump to done
+
+    max_C:
+      move $v0, $s2                         # max = c
+
+    done:                                   # End of program
+
+## LOOPS ##
+  _loops:
+    # The basic structure of loops is having an exit condition and a jump 
+    instruction to continue its execution
+    li $t0, 0
+    while:
+      bgt $t0, 10, end_while                # While $t0 is less than 10, keep iterating
+      addi $t0, $t0, 1                      # Increment the value
+      j while                               # Jump back to the beginning of the loop
+    end_while:
+
+    # 2D Matrix Traversal
+    # Assume that $a0 stores the address of an integer matrix which is 3 x 3
+    li $t0, 0                               # Counter for i
+    li $t1, 0                               # Counter for j
+    matrix_row:
+      bgt $t0, 3, matrix_row_end
+
+      matrix_col:
+        bgt $t1, 3, matrix_col_end
+
+        # Do stuff
+
+        addi $t1, $t1, 1                  # Increment the col counter
+      matrix_col_end:
+
+      # Do stuff
+
+      addi $t0, $t0, 1
+    matrix_row_end:
+
+## FUNCTIONS ##
+  _functions:
+    # Functions are callable procedures that can accept arguments and return 
+    values all denoted with labels, like above
+
+    main:                                 # Programs begin with main func
+      jal return_1                        # jal will store the current PC in $ra
+                                          # and then jump to return_1
+
+      # What if we want to pass in args?
+      # First we must pass in our parameters to the argument registers
+      li $a0, 1
+      li $a1, 2
+      jal sum                             # Now we can call the function
+
+      # How about recursion?
+      # This is a bit more work since we need to make sure we save and restore
+      # the previous PC in $ra since jal will automatically overwrite on each call
+      li $a0, 3
+      jal fact
+
+      li $v0, 10
+      syscall
+    
+    # This function returns 1
+    return_1:
+      li $v0, 1                           # Load val in return register $v0
+      jr $ra                              # Jump back to old PC to continue exec
+
+
+    # Function with 2 args
+    sum:
+      add $v0, $a0, $a1
+      jr $ra                              # Return
+
+    # Recursive function to find factorial
+    fact:
+      addi $sp, $sp, -8                   # Allocate space in stack
+      sw $s0, ($sp)                       # Store reg that holds current num
+      sw $ra, 4($sp)                      # Store previous PC
+
+      li $v0, 1                           # Init return value
+      beq $a0, 0, fact_done               # Finish if param is 0
+
+      # Otherwise, continue recursion
+      move $s0, $a0                       # Copy $a0 to $s0
+      sub $a0, $a0, 1
+      jal fact
+
+      mul $v0, $s0, $v0                   # Multiplication is done
+
+      fact_done:
+        lw $s0, ($sp)
+        lw $ra, ($sp)                     # Restore the PC
+        addi $sp, $sp, 8
+
+        jr $ra
+
+## MACROS ##
+  _macros:
+    # Macros are extremly useful for substituting repeated code blocks with a
+    # single label for better readability
+    # These are in no means substitutes for functions
+    # These must be declared before it is used
+
+    # Macro for printing new lines (since these can be very repetitive)
+    .macro println()
+      la $a0, newline                     # New line string stored here
+      li $v0, 4
+      syscall
+    .end_macro
+
+    println()                             # Assembler will copy that block of
+                                          # code here before running
+
+    # Parameters can be passed in through macros.
+    # These are denoted by a '%' sign with any name you choose
+    .macro print_int(%num)
+      li $v0, 1
+      lw $a0, %num
+      syscall
+    .end_macro
+    
+    li $t0, 1
+    print_int($t0)
+    
+    # We can also pass in immediates for macros
+    .macro immediates(%a, %b)
+      add $t0, %a, %b
+    .end_macro
+
+    immediates(3, 5)
+
+    # Along with passing in labels
+    .macro print(%string)
+      la $a0, %string
+      li $v0, 4
+      syscall
+    .end_macro
+
+    print(hello_world)
+
+## ARRAYS ##
+.data
+  list: .word 3, 0, 1, 2, 6                 # This is an array of words
+  char_arr: .asciiz "hello"                 # This is a char array
+  buffer: .space 128                        # Allocates a block in memory, does
+                                            # not automatically clear
+                                            # These blocks of memory are aligned
+                                            # next each other
+
+.text
+  la $s0, list                              # Load address of list
+  li $t0, 0                                 # Counter
+  li $t1, 5                                 # Length of the list
+
+  loop:
+    bgt $t0, $t1, end_loop
+
+    lw $a0, ($s0)
+    li $v0, 1
+    syscall                                 # Print the number
+
+    addi $s0, $s0, 4                        # Size of a word is 4 bytes
+    addi $t0, $t0, 1                        # Increment
+    j loop
+  end_loop:
+
+## INCLUDE ##
+# You do this to import external files into your program (behind the scenes, 
+# it really just takes whatever code that is in that file and places it where
+# the include statement is)
+.include "somefile.asm"
+
+```

nl-nl/markdown-nl.html.markdown

@@ -12,7 +12,7 @@ Markdown is gecreëerd door John Gruber in 2004. Het is bedoeld om met een gemak
 schrijven syntax te zijn die gemakkelijk omgevormd kan worden naar HTML (en op heden verschillende
 andere formaten)
 
-```markdown
+```md
 <!-- Markdown erft over van HTML, dus ieder HTML bestand is een geldig Markdown
 bestand. Dit betekend ook dat html elementen gebruikt kunnen worden in Markdown
 zoals het commentaar element. Echter, als je een html element maakt in een Markdown 

pt-br/common-lisp-pt.html.markdown

@@ -19,7 +19,7 @@ Outro livro recente e popular é o
 [Land of Lisp](http://landoflisp.com/).
 
 
-```common-lisp
+```lisp
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;; 0. Sintaxe

pt-br/markdown-pt.html.markdown

@@ -14,7 +14,7 @@ escrever sintaxe que converte facilmente em HTML (hoje, suporta outros formatos
 Dê-me feedback tanto quanto você quiser! / Sinta-se livre para a garfar (fork) e 
 puxar o projeto (pull request)
 
-```markdown
+```md
 <!-- Markdown é um superconjunto do HTML, de modo que qualquer arvquivo HTML é 
 um arquivo Markdown válido, isso significa que nós podemos usar elementos HTML 
 em Markdown, como o elemento de comentário, e eles não serão afetados pelo analisador

pt-br/visualbasic-pt.html.markdown

@@ -8,7 +8,7 @@ lang: pt-br
 filename: learnvisualbasic-pt.vb
 ---
 
-```vb
+```
 Module Module1
 
 module Module1

python3.html.markdown

@@ -7,6 +7,7 @@ contributors:
     - ["Zachary Ferguson", "http://github.com/zfergus2"]
     - ["evuez", "http://github.com/evuez"]
     - ["Rommel Martinez", "https://ebzzry.io"]
+    - ["Roberto Fernandez Diaz", "https://github.com/robertofd1995"]
 filename: learnpython3.py
 ---
 
@@ -352,6 +353,8 @@ valid_set = {(1,), 1}
 # Add one more item to the set
 filled_set = some_set
 filled_set.add(5)  # filled_set is now {1, 2, 3, 4, 5}
+# Sets do not have duplicate elements
+filled_set.add(5)  # it remains as before {1, 2, 3, 4, 5}
 
 # Do set intersection with &
 other_set = {3, 4, 5, 6}

ru-ru/markdown-ru.html.markdown

@@ -36,7 +36,7 @@ lang: ru-ru
 Markdown является надмножеством HTML, поэтому любой HTML-файл является
 корректным документом Markdown.
 
- ```markdown
+ ```md
 <!-- Это позволяет использовать напрямую
 любые элементы HTML-разметки, такие, например, как этот комментарий.
   Встроенные в документ HTML-элементы не затрагиваются парсером Markdown

ruby.html.markdown

@@ -16,19 +16,20 @@ contributors:
   - ["Persa Zula", "http://persazula.com"]
   - ["Jake Faris", "https://github.com/farisj"]
   - ["Corey Ward", "https://github.com/coreyward"]
+  - ["Jannik Siebert", "https://github.com/janniks"]
 ---
 
 ```ruby
 # This is a comment
 
 # In Ruby, (almost) everything is an object.
-# This includes numbers…
+# This includes numbers...
 3.class #=> Integer
 
-# …strings…
+# ...and strings...
 "Hello".class #=> String
 
-# …even methods!
+# ...and even methods!
 "Hello".method(:class).class #=> Method
 
 # Some basic arithmetic
@@ -67,7 +68,7 @@ false.class #=> FalseClass
 1 != 1 #=> false
 2 != 1 #=> true
 
-# apart from false itself, nil is the only other 'falsey' value
+# Apart from false itself, nil is the only other 'falsey' value
 
 !!nil   #=> false
 !!false #=> false
@@ -111,33 +112,33 @@ placeholder = 'use string interpolation'
 'hello ' + 3.to_s #=> "hello 3"
 "hello #{3}" #=> "hello 3"
 
-# Combine strings and operators
+# ...or combine strings and operators
 'hello ' * 3 #=> "hello hello hello "
 
-# Append to string
+# ...or append to string
 'hello' << ' world' #=> "hello world"
 
-# print to the output with a newline at the end
+# You can print to the output with a newline at the end
 puts "I'm printing!"
 #=> I'm printing!
 #=> nil
 
-# print to the output without a newline
+# ...or print to the output without a newline
 print "I'm printing!"
-#=> I'm printing! => nil
+#=> "I'm printing!" => nil
 
 # Variables
 x = 25 #=> 25
 x #=> 25
 
-# Note that assignment returns the value assigned
+# Note that assignment returns the value assigned.
-# This means you can do multiple assignment:
+# This means you can do multiple assignment.
 
 x = y = 10 #=> 10
 x #=> 10
 y #=> 10
 
-# By convention, use snake_case for variable names
+# By convention, use snake_case for variable names.
 snake_case = true
 
 # Use descriptive variable names
@@ -146,7 +147,7 @@ m = '/bad/name/'
 
 # Symbols are immutable, reusable constants represented internally by an
 # integer value. They're often used instead of strings to efficiently convey
-# specific, meaningful values
+# specific, meaningful values.
 
 :pending.class #=> Symbol
 
@@ -158,82 +159,82 @@ status == 'pending' #=> false
 
 status == :approved #=> false
 
-Strings can be converted into symbols and vice versa:
+# Strings can be converted into symbols and vice versa.
-
 status.to_s #=> "pending"
 "argon".to_sym #=> :argon
 
 # Arrays
 
-# This is an array
+# This is an array.
 array = [1, 2, 3, 4, 5] #=> [1, 2, 3, 4, 5]
 
-# Arrays can contain different types of items
+# Arrays can contain different types of items.
-
 [1, 'hello', false] #=> [1, "hello", false]
 
-# Arrays can be indexed
+# Arrays can be indexed.
-# From the front
+# From the front...
 array[0] #=> 1
 array.first #=> 1
 array[12] #=> nil
 
-# Like arithmetic, [var] access
+# ...or from the back...
-# is just syntactic sugar
-# for calling a method [] on an object
-array.[] 0 #=> 1
-array.[] 12 #=> nil
-
-# From the end
 array[-1] #=> 5
 array.last #=> 5
 
-# With a start index and length
+# ...or with a start index and length...
 array[2, 3] #=> [3, 4, 5]
 
-# Reverse an Array
+# ...or with a range...
+array[1..3] #=> [2, 3, 4]
+
+# You can reverse an Array.
 a = [1,2,3]
 a.reverse! #=> [3,2,1]
 
-# Or with a range
+# Like arithmetic, [var] access is just syntactic sugar
-array[1..3] #=> [2, 3, 4]
+# for calling a method '[]' on an object.
+array.[] 0 #=> 1
+array.[] 12 #=> nil
 
-# Add to an array like this
+# You can add to an array...
 array << 6 #=> [1, 2, 3, 4, 5, 6]
 # Or like this
 array.push(6) #=> [1, 2, 3, 4, 5, 6]
 
-# Check if an item exists in an array
+# ...and check if an item exists in an array
 array.include?(1) #=> true
 
 # Hashes are Ruby's primary dictionary with key/value pairs.
-# Hashes are denoted with curly braces:
+# Hashes are denoted with curly braces.
 hash = { 'color' => 'green', 'number' => 5 }
 
 hash.keys #=> ['color', 'number']
 
-# Hashes can be quickly looked up by key:
+# Hashes can be quickly looked up by key.
-hash['color'] #=> 'green'
+hash['color'] #=> "green"
 hash['number'] #=> 5
 
-# Asking a hash for a key that doesn't exist returns nil:
+# Asking a hash for a key that doesn't exist returns nil.
 hash['nothing here'] #=> nil
 
-# When using symbols for keys in a hash, you can use this alternate syntax:
+# When using symbols for keys in a hash, you can use an alternate syntax.
 
-new_hash = { defcon: 3, action: true }
+hash = { :defcon => 3, :action => true }
+hash.keys #=> [:defcon, :action]
 
-new_hash.keys #=> [:defcon, :action]
+hash = { defcon: 3, action: true }
+hash.keys #=> [:defcon, :action]
 
 # Check existence of keys and values in hash
-new_hash.key?(:defcon) #=> true
+hash.key?(:defcon) #=> true
-new_hash.value?(3) #=> true
+hash.value?(3) #=> true
 
-# Tip: Both Arrays and Hashes are Enumerable
+# Tip: Both Arrays and Hashes are Enumerable!
-# They share a lot of useful methods such as each, map, count, and more
+# They share a lot of useful methods such as each, map, count, and more.
 
 # Control structures
 
+# Conditionals
 if true
   'if statement'
 elsif false
@@ -242,28 +243,26 @@ else
   'else, also optional'
 end
 
-
+# Loops
 # In Ruby, traditional `for` loops aren't very common. Instead, these 
-# basic loops are implemented using enumerable, which hinges on `each`:
+# basic loops are implemented using enumerable, which hinges on `each`.
-
 (1..5).each do |counter|
   puts "iteration #{counter}"
 end
 
-# Which is roughly equivalent to this, which is unusual to see in Ruby:
+# Which is roughly equivalent to the following, which is unusual to see in Ruby.
-
 for counter in 1..5
   puts "iteration #{counter}"
 end
 
-# The `do |variable| ... end` construct above is called a “block”. Blocks are similar
+# The `do |variable| ... end` construct above is called a 'block'. Blocks are similar
 # to lambdas, anonymous functions or closures in other programming languages. They can
 # be passed around as objects, called, or attached as methods.
 #
-# The "each" method of a range runs the block once for each element of the range.
+# The 'each' method of a range runs the block once for each element of the range.
 # The block is passed a counter as a parameter.
 
-# You can also surround blocks in curly brackets:
+# You can also surround blocks in curly brackets.
 (1..5).each { |counter| puts "iteration #{counter}" }
 
 # The contents of data structures can also be iterated using each.
@@ -274,8 +273,8 @@ hash.each do |key, value|
   puts "#{key} is #{value}"
 end
 
-# If you still need an index you can use "each_with_index" and define an index
+# If you still need an index you can use 'each_with_index' and define an index
-# variable
+# variable.
 array.each_with_index do |element, index|
   puts "#{element} is number #{index} in the array"
 end
@@ -291,9 +290,9 @@ end
 #=> iteration 4
 #=> iteration 5
 
-# There are a bunch of other helpful looping functions in Ruby,
+# There are a bunch of other helpful looping functions in Ruby.
-# for example "map", "reduce", "inject", the list goes on. Map,
+# For example: 'map', 'reduce', 'inject', the list goes on.
-# for instance, takes the array it's looping over, does something
+# Map, for instance, takes the array it's looping over, does something
 # to it as defined in your block, and returns an entirely new array.
 array = [1,2,3,4,5]
 doubled = array.map do |element|
@@ -304,6 +303,7 @@ puts doubled
 puts array
 #=> [1,2,3,4,5]
 
+# Case construct
 grade = 'B'
 
 case grade
@@ -322,7 +322,7 @@ else
 end
 #=> "Better luck next time"
 
-# cases can also use ranges
+# Cases can also use ranges
 grade = 82
 case grade
 when 90..100
@@ -334,9 +334,9 @@ else
 end
 #=> "OK job"
 
-# exception handling:
+# Exception handling
 begin
-  # code here that might raise an exception
+  # Code here that might raise an exception
   raise NoMemoryError, 'You ran out of memory.'
 rescue NoMemoryError => exception_variable
   puts 'NoMemoryError was raised', exception_variable
@@ -354,10 +354,10 @@ def double(x)
   x * 2
 end
 
-# Methods (and blocks) implicitly return the value of the last statement
+# Methods (and blocks) implicitly return the value of the last statement.
 double(2) #=> 4
 
-# Parentheses are optional where the interpretation is unambiguous
+# Parentheses are optional where the interpretation is unambiguous.
 double 3 #=> 6
 
 double double 3 #=> 12
@@ -366,15 +366,14 @@ def sum(x, y)
   x + y
 end
 
-# Method arguments are separated by a comma
+# Method arguments are separated by a comma.
 sum 3, 4 #=> 7
 
 sum sum(3, 4), 5 #=> 12
 
 # yield
-# All methods have an implicit, optional block parameter
+# All methods have an implicit, optional block parameter.
-# it can be called with the 'yield' keyword
+# Tt can be called with the 'yield' keyword.
-
 def surround
   puts '{'
   yield
@@ -383,45 +382,43 @@ end
 
 surround { puts 'hello world' }
 
-# {
+#=> {
-# hello world
+#=> hello world
-# }
+#=> }
 
-
+# Blocks can be converted into a 'proc' object, which wraps the block 
-# Blocks can be converted into a `proc` object, which wraps the block 
 # and allows it to be passed to another method, bound to a different scope,
 # or manipulated otherwise. This is most common in method parameter lists,
-# where you frequently see a trailing `&block` parameter that will accept 
+# where you frequently see a trailing '&block' parameter that will accept 
-# the block, if one is given, and convert it to a `Proc`. The naming here is
+# the block, if one is given, and convert it to a 'Proc'. The naming here is
-# convention; it would work just as well with `&pineapple`:
+# convention; it would work just as well with '&pineapple'.
 def guests(&block)
   block.class #=> Proc
   block.call(4)
 end
 
-# The `call` method on the Proc is similar to calling `yield` when a block is 
+# The 'call' method on the Proc is similar to calling 'yield' when a block is 
-# present. The arguments passed to `call` will be forwarded to the block as arugments:
+# present. The arguments passed to 'call' will be forwarded to the block as arugments.
 
 guests { |n| "You have #{n} guests." }
 # => "You have 4 guests."
 
-# You can pass a list of arguments, which will be converted into an array
+# You can pass a list of arguments, which will be converted into an array.
-# That's what splat operator ("*") is for
+# That's what splat operator ("*") is for.
 def guests(*array)
   array.each { |guest| puts guest }
 end
 
 # Destructuring
 
-# Ruby will automatically destructure arrays on assignment to multiple variables:
+# Ruby will automatically destructure arrays on assignment to multiple variables.
 a, b, c = [1, 2, 3]
 a #=> 1
 b #=> 2
 c #=> 3
 
 # In some cases, you will want to use the splat operator: `*` to prompt destructuring
-# of an array into a list:
+# of an array into a list.
-
 ranked_competitors = ["John", "Sally", "Dingus", "Moe", "Marcy"]
 
 def best(first, second, third)
@@ -430,7 +427,7 @@ end
 
 best *ranked_competitors.first(3) #=> Winners are John, Sally, and Dingus.
 
-# The splat operator can also be used in parameters:
+# The splat operator can also be used in parameters.
 def best(first, second, third, *others)
   puts "Winners are #{first}, #{second}, and #{third}."
   puts "There were #{others.count} other participants."
@@ -440,21 +437,23 @@ best *ranked_competitors
 #=> Winners are John, Sally, and Dingus.
 #=> There were 2 other participants.
 
-# By convention, all methods that return booleans end with a question mark
+# By convention, all methods that return booleans end with a question mark.
-5.even? # false
+5.even? #=> false
-5.odd? # true
+5.odd? #=> true
 
-# And if a method ends with an exclamation mark, it does something destructive
+# By convention, if a method name ends with an exclamation mark, it does something destructive
 # like mutate the receiver. Many methods have a ! version to make a change, and
-# a non-! version to just return a new changed version
+# a non-! version to just return a new changed version.
 company_name = "Dunder Mifflin"
 company_name.upcase #=> "DUNDER MIFFLIN"
 company_name #=> "Dunder Mifflin"
-company_name.upcase! # we're mutating company_name this time!
+# We're mutating company_name this time.
+company_name.upcase! #=> "DUNDER MIFFLIN"
 company_name #=> "DUNDER MIFFLIN"
 
+# Classes
 
-# Define a class with the class keyword
+# You can define a class with the 'class' keyword.
 class Human
 
   # A class variable. It is shared by all instances of this class.
@@ -462,7 +461,7 @@ class Human
 
   # Basic initializer
   def initialize(name, age = 0)
-    # Assign the argument to the "name" instance variable for the instance
+    # Assign the argument to the 'name' instance variable for the instance.
     @name = name
     # If no age given, we will fall back to the default in the arguments list.
     @age = age
@@ -478,10 +477,10 @@ class Human
     @name
   end
 
-  # The above functionality can be encapsulated using the attr_accessor method as follows
+  # The above functionality can be encapsulated using the attr_accessor method as follows.
   attr_accessor :name
 
-  # Getter/setter methods can also be created individually like this
+  # Getter/setter methods can also be created individually like this.
   attr_reader :name
   attr_writer :name
 
@@ -496,13 +495,11 @@ class Human
   end
 end
 
-
+# Instantiating of a class
-# Instantiate a class
 jim = Human.new('Jim Halpert')
-
 dwight = Human.new('Dwight K. Schrute')
 
-# Let's call a couple of methods
+# You can call the methods of the generated object.
 jim.species #=> "H. sapiens"
 jim.name #=> "Jim Halpert"
 jim.name = "Jim Halpert II" #=> "Jim Halpert II"
@@ -510,30 +507,30 @@ jim.name #=> "Jim Halpert II"
 dwight.species #=> "H. sapiens"
 dwight.name #=> "Dwight K. Schrute"
 
-# Call the class method
+# Calling of a class method
 Human.say('Hi') #=> "Hi"
 
 # Variable's scopes are defined by the way we name them.
-# Variables that start with $ have global scope
+# Variables that start with $ have global scope.
 $var = "I'm a global var"
 defined? $var #=> "global-variable"
 
-# Variables that start with @ have instance scope
+# Variables that start with @ have instance scope.
 @var = "I'm an instance var"
 defined? @var #=> "instance-variable"
 
-# Variables that start with @@ have class scope
+# Variables that start with @@ have class scope.
 @@var = "I'm a class var"
 defined? @@var #=> "class variable"
 
-# Variables that start with a capital letter are constants
+# Variables that start with a capital letter are constants.
 Var = "I'm a constant"
 defined? Var #=> "constant"
 
-# Class is also an object in ruby. So class can have instance variables.
+# Class is also an object in ruby. So a class can have instance variables.
-# Class variable is shared among the class and all of its descendants.
+# A class variable is shared among the class and all of its descendants.
 
-# base class
+# Base class
 class Human
   @@foo = 0
 
@@ -546,18 +543,17 @@ class Human
   end
 end
 
-# derived class
+# Derived class
 class Worker < Human
 end
 
-Human.foo # 0
+Human.foo #=> 0
-Worker.foo # 0
+Worker.foo #=> 0
 
-Human.foo = 2 # 2
+Human.foo = 2
-Worker.foo # 2
+Worker.foo #=> 2
-
-# Class instance variable is not shared by the class's descendants.
 
+# A class instance variable is not shared by the class's descendants.
 class Human
   @bar = 0
 
@@ -573,8 +569,8 @@ end
 class Doctor < Human
 end
 
-Human.bar # 0
+Human.bar #=> 0
-Doctor.bar # nil
+Doctor.bar #=> nil
 
 module ModuleExample
   def foo
@@ -582,9 +578,8 @@ module ModuleExample
   end
 end
 
-# Including modules binds their methods to the class instances
+# Including modules binds their methods to the class instances.
-# Extending modules binds their methods to the class itself
+# Extending modules binds their methods to the class itself.
-
 class Person
   include ModuleExample
 end
@@ -593,13 +588,12 @@ class Book
   extend ModuleExample
 end
 
-Person.foo     # => NoMethodError: undefined method `foo' for Person:Class
+Person.foo     #=> NoMethodError: undefined method `foo' for Person:Class
-Person.new.foo # => 'foo'
+Person.new.foo #=> "foo"
-Book.foo       # => 'foo'
+Book.foo       #=> "foo"
-Book.new.foo   # => NoMethodError: undefined method `foo'
+Book.new.foo   #=> NoMethodError: undefined method `foo'
 
 # Callbacks are executed when including and extending a module
-
 module ConcernExample
   def self.included(base)
     base.extend(ClassMethods)
@@ -623,10 +617,10 @@ class Something
   include ConcernExample
 end
 
-Something.bar     # => 'bar'
+Something.bar     #=> "bar"
-Something.qux     # => NoMethodError: undefined method `qux'
+Something.qux     #=> NoMethodError: undefined method `qux'
-Something.new.bar # => NoMethodError: undefined method `bar'
+Something.new.bar #=> NoMethodError: undefined method `bar'
-Something.new.qux # => 'qux'
+Something.new.qux #=> "qux"
 ```
 
 ## Additional resources

toml.html.markdown

@@ -12,7 +12,7 @@ It is an alternative to YAML and JSON. It aims to be more human friendly than JS
 Be warned, TOML's spec is still changing a lot. Until it's marked as 1.0, you
 should assume that it is unstable and act accordingly. This document follows TOML v0.4.0. 
 
-```toml
+```
 # Comments in TOML look like this.
 
 ################

tr-tr/markdown-tr.html.markdown

@@ -11,7 +11,7 @@ filename: markdown-tr.md
 Markdown, 2004 yılında John Gruber tarafından oluşturuldu. Asıl amacı kolay okuma ve yazmayı sağlamakla beraber kolayca HTML (artık bir çok diğer formatlara) dönüşüm sağlamaktır.
 
 
-```markdown
+```md
 <!-- Markdown, HTML'i kapsar, yani her HTML dosyası geçerli bir Markdown dosyasıdır, bu demektir
 ki Markdown içerisinde HTML etiketleri kullanabiliriz, örneğin bu yorum elementi, ve
 markdown işleyicisinde etki etmezler. Fakat, markdown dosyası içerisinde HTML elementi oluşturursanız,

uk-ua/python-ua.html.markdown

@@ -0,0 +1,818 @@
+---
+language: python
+lang: uk-ua
+contributors:
+    - ["Louie Dinh", "http://ldinh.ca"]
+    - ["Amin Bandali", "https://aminb.org"]
+    - ["Andre Polykanine", "https://github.com/Oire"]
+    - ["evuez", "http://github.com/evuez"]
+    - ["asyne", "https://github.com/justblah"]
+    - ["habi", "http://github.com/habi"]
+translators:
+    - ["Oleg Gromyak", "https://github.com/ogroleg"]
+filename: learnpython-ua.py
+---
+
+Мову Python створив Гвідо ван Россум на початку 90-х. Наразі це одна з 
+найбільш популярних мов. Я закохався у Python завдяки простому і зрозумілому
+синтаксису. Це майже як виконуваний псевдокод.
+
+З вдячністю чекаю ваших відгуків: [@louiedinh](http://twitter.com/louiedinh)
+або louiedinh [at] [поштовий сервіс від Google]
+
+Примітка: Ця стаття стосується Python 2.7, проте має працювати і 
+у інших версіях Python 2.x. Python 2.7 підходить до кінця свого терміну, 
+його підтримку припинять у 2020, тож наразі краще починати вивчення Python 
+з версії 3.x.
+Аби вивчити Python 3.x, звертайтесь до статті по Python 3.
+
+```python
+# Однорядкові коментарі починаються з символу решітки.
+
+""" Текст, що займає декілька рядків,
+    може бути записаний з використанням 3 знаків " і 
+    зазвичай використовується у якості
+    вбудованої документації
+"""
+
+####################################################
+## 1. Примітивні типи даних та оператори
+####################################################
+
+# У вас є числа
+3  # => 3
+
+# Математика працює досить передбачувано
+1 + 1  # => 2
+8 - 1  # => 7
+10 * 2  # => 20
+35 / 5  # => 7
+
+# А ось з діленням все трохи складніше. Воно цілочисельне і результат
+# автоматично округлюється у меншу сторону.
+5 / 2  # => 2
+
+# Аби правильно ділити, спершу варто дізнатися про числа
+# з плаваючою комою.
+2.0  # Це число з плаваючою комою
+11.0 / 4.0  # => 2.75 ох... Так набагато краще
+
+# Результат цілочисельного ділення округлюється у меншу сторону
+# як для додатніх, так і для від'ємних чисел.
+5 // 3  # => 1
+5.0 // 3.0  # => 1.0  # Працює і для чисел з плаваючою комою
+-5 // 3  # => -2
+-5.0 // 3.0  # => -2.0
+
+# Зверніть увагу, що ми також можемо імпортувати модуль для ділення, 
+# див. розділ Модулі
+# аби звичне ділення працювало при використанні лише '/'.
+from __future__ import division
+
+11 / 4  # => 2.75  ...звичне ділення
+11 // 4  # => 2 ...цілочисельне ділення
+
+# Залишок від ділення
+7 % 3  # => 1
+
+# Піднесення до степеня
+2 ** 4  # => 16
+
+# Приорітет операцій вказується дужками
+(1 + 3) * 2  # => 8
+
+# Логічні оператори
+# Зверніть увагу: ключові слова «and» і «or» чутливі до регістру букв
+True and False  # => False
+False or True  # => True
+
+# Завважте, що логічні оператори також використовуються і з цілими числами
+0 and 2  # => 0
+-5 or 0  # => -5
+0 == False  # => True
+2 == True  # => False
+1 == True  # => True
+
+# Для заперечення використовується not
+not True  # => False
+not False  # => True
+
+# Рівність — це ==
+1 == 1  # => True
+2 == 1  # => False
+
+# Нерівність — це !=
+1 != 1  # => False
+2 != 1  # => True
+
+# Ще трохи порівнянь
+1 < 10  # => True
+1 > 10  # => False
+2 <= 2  # => True
+2 >= 2  # => True
+
+# Порівняння можуть бути записані ланцюжком!
+1 < 2 < 3  # => True
+2 < 3 < 2  # => False
+
+# Рядки позначаються символом " або '
+"Це рядок."
+'Це теж рядок.'
+
+# І рядки також можна додавати!
+"Привіт " + "світ!" # => "Привіт світ!"
+# Рядки можна додавати і без '+'
+"Привіт " "світ!"  # => "Привіт світ!"
+
+# ... або множити
+"Привіт" * 3  # => "ПривітПривітПривіт"
+
+# З рядком можна працювати як зі списком символів
+"Це рядок"[0]  # => 'Ц'
+
+# Ви можете дізнатися довжину рядка
+len("Це рядок")  # => 8
+
+# Символ % використовується для форматування рядків, наприклад:
+"%s можуть бути %s" % ("рядки", "інтерпольовані")
+
+# Новий спосіб форматування рядків — використання методу format.
+# Це бажаний спосіб.
+"{} є {}".format("Це", "заповнювач")
+"{0} можуть бути {1}".format("рядки", "форматовані")
+# Якщо ви не хочете рахувати, то можете скористатися ключовими словами.
+"{name} хоче з'істи {food}".format(name="Боб", food="лазанью")
+
+# None - це об'єкт
+None  # => None
+
+# Не використовуйте оператор рівності '=='' для порівняння 
+# об'єктів з None. Використовуйте для цього «is»
+"etc" is None  # => False
+None is None  # => True
+
+# Оператор 'is' перевіряє ідентичність об'єктів. Він не 
+# дуже корисний при роботі з примітивними типами, проте 
+# незамінний при роботі з об'єктами.
+
+# None, 0 і порожні рядки/списки рівні False.
+# Всі інші значення рівні True
+bool(0)  # => False
+bool("")  # => False
+
+
+####################################################
+## 2. Змінні та колекції
+####################################################
+
+# В Python є оператор print
+print "Я Python. Приємно познайомитись!"  # => Я Python. Приємно познайомитись!
+
+# Отримати дані з консолі просто
+input_string_var = raw_input(
+    "Введіть щось: ")  # Повертає дані у вигляді рядка
+input_var = input("Введіть щось: ")  # Працює з даними як з кодом на python
+# Застереження: будьте обережні при використанні методу input()
+
+# Оголошувати змінні перед ініціалізацією не потрібно.
+some_var = 5  # За угодою використовується нижній_регістр_з_підкресленнями
+some_var  # => 5
+
+# При спробі доступу до неініціалізованої змінної
+# виникне виняткова ситуація.
+# Див. розділ Потік управління, аби дізнатись про винятки більше.
+some_other_var  # Помилка в імені
+
+# if може використовуватися як вираз
+# Такий запис еквівалентний тернарному оператору '?:' у мові С
+"yahoo!" if 3 > 2 else 2  # => "yahoo!"
+
+# Списки зберігають послідовності
+li = []
+# Можна одразу створити заповнений список
+other_li = [4, 5, 6]
+
+# Об'єкти додаються у кінець списку за допомогою методу append
+li.append(1)  # li тепер дорівнює [1]
+li.append(2)  # li тепер дорівнює [1, 2]
+li.append(4)  # li тепер дорівнює [1, 2, 4]
+li.append(3)  # li тепер дорівнює [1, 2, 4, 3]
+# І видаляються з кінця методом pop
+li.pop()  # => повертає 3 і li стає рівним [1, 2, 4]
+# Повернемо елемент назад
+li.append(3)  # li тепер знову дорівнює [1, 2, 4, 3]
+
+# Поводьтесь зі списком як зі звичайним масивом
+li[0]  # => 1
+# Присвоюйте нові значення вже ініціалізованим індексам за допомогою =
+li[0] = 42
+li[0]  # => 42
+li[0] = 1  # Зверніть увагу: повертаємось до попереднього значення
+# Звертаємось до останнього елементу
+li[-1]  # => 3
+
+# Спроба вийти за границі масиву призводить до помилки в індексі
+li[4]  # помилка в індексі
+
+# Можна звертатися до діапазону, використовуючи так звані зрізи
+# (Для тих, хто любить математику: це називається замкнуто-відкритий інтервал).
+li[1:3]  # => [2, 4]
+# Опускаємо початок
+li[2:]  # => [4, 3]
+# Опускаємо кінець
+li[:3]  # => [1, 2, 4]
+# Вибираємо кожен другий елемент
+li[::2]  # => [1, 4]
+# Перевертаємо список
+li[::-1]  # => [3, 4, 2, 1]
+# Використовуйте суміш вищеназваного для більш складних зрізів
+# li[початок:кінець:крок]
+
+# Видаляємо довільні елементи зі списку оператором del
+del li[2]  # li тепер [1, 2, 3]
+
+# Ви можете додавати списки
+li + other_li  # => [1, 2, 3, 4, 5, 6]
+# Зверніть увагу: значення li та other_li при цьому не змінились.
+
+# Поєднувати списки можна за допомогою методу extend
+li.extend(other_li)  # Тепер li дорівнює [1, 2, 3, 4, 5, 6]
+
+# Видалити перше входження значення
+li.remove(2)  # Тепер li дорівнює [1, 3, 4, 5, 6]
+li.remove(2)  # Помилка значення, оскільки у списку li немає 2
+
+# Вставити елемент за вказаним індексом
+li.insert(1, 2)  # li знову дорівнює [1, 2, 3, 4, 5, 6]
+
+# Отримати індекс першого знайденого елементу
+li.index(2)  # => 1
+li.index(7)  # Помилка значення, оскільки у списку li немає 7
+
+# Перевірити елемент на входження у список можна оператором in
+1 in li  # => True
+
+# Довжина списку обчислюється за допомогою функції len
+len(li)  # => 6
+
+# Кортежі схожі на списки, лише незмінні
+tup = (1, 2, 3)
+tup[0]  # => 1
+tup[0] = 3  # Виникає помилка типу
+
+# Все те ж саме можна робити і з кортежами
+len(tup)  # => 3
+tup + (4, 5, 6)  # => (1, 2, 3, 4, 5, 6)
+tup[:2]  # => (1, 2)
+2 in tup  # => True
+
+# Ви можете розпаковувати кортежі (або списки) у змінні
+a, b, c = (1, 2, 3)  # a == 1, b == 2 и c == 3
+d, e, f = 4, 5, 6  # дужки можна опустити
+# Кортежі створюються за замовчуванням, якщо дужки опущено
+g = 4, 5, 6  # => (4, 5, 6)
+# Дивіться, як легко обміняти значення двох змінних
+e, d = d, e  # тепер d дорівнює 5, а e дорівнює 4
+
+# Словники містять асоціативні масиви
+empty_dict = {}
+# Ось так описується попередньо заповнений словник
+filled_dict = {"one": 1, "two": 2, "three": 3}
+
+# Значення можна отримати так само, як і зі списку
+filled_dict["one"]  # => 1
+
+# Можна отримати всі ключі у виді списку за допомогою методу  keys
+filled_dict.keys()  # => ["three", "two", "one"]
+# Примітка: збереження порядку ключів у словників не гарантується
+# Ваші результати можуть не співпадати з цими.
+
+# Можна отримати і всі значення у вигляді списку, використовуйте метод values
+filled_dict.values()  # => [3, 2, 1]
+# Те ж зауваження щодо порядку ключів діє і тут
+
+# Отримуйте всі пари ключ-значення у вигляді списку кортежів 
+# за допомогою "items()"
+filled_dict.items()  # => [("one", 1), ("two", 2), ("three", 3)]
+
+# За допомогою оператору in можна перевіряти ключі на входження у словник
+"one" in filled_dict # => True
+1 in filled_dict  # => False
+
+# Спроба отримати значення за неіснуючим ключем викине помилку ключа
+filled_dict["four"]  # помилка ключа
+
+# Аби уникнути цього, використовуйте метод get()
+filled_dict.get("one")  # => 1
+filled_dict.get("four")  # => None
+# Метод get також приймає аргумент за замовчуванням, значення якого буде
+# повернуто при відсутності вказаного ключа
+filled_dict.get("one", 4)  # => 1
+filled_dict.get("four", 4)  # => 4
+# Зверніть увагу, що filled_dict.get("four") все ще => None
+# (get не встановлює значення елементу словника)
+
+# Присвоюйте значення ключам так само, як і в списках
+filled_dict["four"] = 4  # тепер filled_dict["four"] => 4
+
+# Метод setdefault() вставляє пару ключ-значення лише 
+# за відсутності такого ключа
+filled_dict.setdefault("five", 5)  #  filled_dict["five"] повертає 5
+filled_dict.setdefault("five", 6)  #  filled_dict["five"] все ще повертає 5
+
+
+# Множини містять... ну, загалом, множини
+# (які схожі на списки, проте в них не може бути елементів, які повторюються)
+empty_set = set()
+# Ініціалізація множини набором значень
+some_set = set([1,2,2,3,4])  # some_set тепер дорівнює set([1, 2, 3, 4])
+
+# Порядок не гарантовано, хоча інколи множини виглядають відсортованими
+another_set = set([4, 3, 2, 2, 1])  # another_set тепер set([1, 2, 3, 4])
+
+# Починаючи з Python 2.7, ви можете використовувати {}, аби створити множину
+filled_set = {1, 2, 2, 3, 4}  # => {1, 2, 3, 4}
+
+# Додавання нових елементів у множину
+filled_set.add(5)  # filled_set тепер дорівнює {1, 2, 3, 4, 5}
+
+# Перетин множин: &
+other_set = {3, 4, 5, 6}
+filled_set & other_set  # => {3, 4, 5}
+
+# Об'єднання множин: |
+filled_set | other_set  # => {1, 2, 3, 4, 5, 6}
+
+# Різниця множин: -
+{1,2,3,4} - {2,3,5}  # => {1, 4}
+
+# Симетрична різниця множин: ^
+{1, 2, 3, 4} ^ {2, 3, 5}  # => {1, 4, 5}
+
+# Перевіряємо чи множина зліва є надмножиною множини справа
+{1, 2} >= {1, 2, 3}  # => False
+
+# Перевіряємо чи множина зліва є підмножиною множини справа
+{1, 2} <= {1, 2, 3}  # => True
+
+# Перевірка на входження у множину: in
+2 in filled_set  # => True
+10 in filled_set  # => False
+
+
+####################################################
+## 3. Потік управління
+####################################################
+
+# Для початку створимо змінну
+some_var = 5
+
+# Так виглядає вираз if. Відступи у python дуже важливі!
+# результат: «some_var менше, ніж 10»
+if some_var > 10:
+    print("some_var набагато більше, ніж 10.")
+elif some_var < 10:  # Вираз elif є необов'язковим.
+    print("some_var менше, ніж 10.")
+else:  # Це теж необов'язково.
+    print("some_var дорівнює 10.")
+
+
+"""
+Цикли For проходять по спискам
+
+Результат:
+    собака — це ссавець
+    кішка — це ссавець
+    миша — це ссавець
+"""
+for animal in ["собака", "кішка", "миша"]:
+    # Можете використовувати оператор {0} для інтерполяції форматованих рядків
+    print "{0} — це ссавець".format(animal) 
+    
+"""
+"range(число)" повертає список чисел
+від нуля до заданого числа
+Друкує:
+    0
+    1
+    2
+    3
+"""
+for i in range(4):
+    print(i)
+"""
+"range(нижня_границя, верхня_границя)" повертає список чисел
+від нижньої границі до верхньої
+Друкує:
+    4
+    5
+    6
+    7
+"""
+for i in range(4, 8):
+    print i
+
+"""
+Цикли while продовжуються до тих пір, поки вказана умова не стане хибною.
+Друкує:
+    0
+    1
+    2
+    3
+"""
+x = 0
+while x < 4:
+    print(x)
+    x += 1  # Короткий запис для x = x + 1
+
+# Обробляйте винятки блоками try/except
+
+# Працює у Python 2.6 і вище:
+try:
+    # Аби створити виняток, використовується raise
+    raise IndexError("Помилка у індексі!")
+except IndexError as e:
+    pass  # pass — оператор, який нічого не робить. Зазвичай тут відбувається
+    # відновлення після помилки.
+except (TypeError, NameError):
+    pass  # Винятки можна обробляти групами, якщо потрібно.
+else:  # Необов'язковий вираз. Має слідувати за останнім блоком except
+    print("Все добре!")   # Виконається лише якщо не було ніяких винятків
+finally:  # Виконується у будь-якому випадку
+    print "Тут ми можемо звільнити ресурси"
+
+# Замість try/finally для звільнення ресурсів 
+# ви можете використовувати вираз with
+with open("myfile.txt") as f:
+    for line in f:
+        print line
+
+
+####################################################
+## 4. Функції
+####################################################
+
+# Використовуйте def для створення нових функцій
+def add(x, y):
+    print "x дорівнює {0}, а y дорівнює {1}".format(x, y)
+    return x + y  # Повертайте результат за допомогою ключового слова return
+
+
+# Виклик функції з аргументами
+add(5, 6)  # => друкує «x дорівнює 5, а y дорівнює 6» і повертає 11
+
+# Інший спосіб виклику функції — виклик з іменованими аргументами
+add(y=6, x=5)  # Іменовані аргументи можна вказувати у будь-якому порядку
+
+
+# Ви можете визначити функцію, яка приймає змінну кількість аргументів,
+# які будуть інтерпретовані як кортеж, за допомогою *
+def varargs(*args):
+    return args
+
+
+varargs(1, 2, 3)  # => (1,2,3)
+
+
+# А також можете визначити функцію, яка приймає змінне число
+# іменованих аргументів, котрі будуть інтерпретовані як словник, за допомогою **
+def keyword_args(**kwargs):
+    return kwargs
+
+
+# Давайте подивимось що з цього вийде
+keyword_args(big="foot", loch="ness")  # => {"big": "foot", "loch": "ness"}
+
+# Якщо хочете, можете використовувати обидва способи одночасно
+def all_the_args(*args, **kwargs):
+    print(args)
+    print(kwargs)
+
+
+"""
+all_the_args(1, 2, a=3, b=4) друкує:
+    (1, 2)
+    {"a": 3, "b": 4}
+"""
+
+# Коли викликаєте функції, то можете зробити навпаки!
+# Використовуйте символ * аби розпакувати позиційні аргументи і 
+# ** для іменованих аргументів
+args = (1, 2, 3, 4)
+kwargs = {"a": 3, "b": 4}
+all_the_args(*args)  # еквівалентно foo(1, 2, 3, 4)
+all_the_args(**kwargs)  # еквівалентно foo(a=3, b=4)
+all_the_args(*args, **kwargs)  # еквівалентно foo(1, 2, 3, 4, a=3, b=4)
+
+# ви можете передавати довільне число позиційних або іменованих аргументів
+# іншим функціям, які їх приймають, розпаковуючи за допомогою
+# * або ** відповідно
+def pass_all_the_args(*args, **kwargs):
+    all_the_args(*args, **kwargs)
+    print varargs(*args)
+    print keyword_args(**kwargs)
+
+
+# Область визначення функцій
+x = 5
+
+
+def set_x(num):
+    # Локальна змінна x - не те ж саме, що глобальна змінна x
+    x = num  # => 43
+    print x  # => 43
+
+
+def set_global_x(num):
+    global x
+    print x  # => 5
+    x = num  # глобальна змінна x тепер дорівнює 6
+    print x  # => 6
+
+
+set_x(43)
+set_global_x(6)
+
+# В Python функції є об'єктами першого класу
+def create_adder(x):
+    def adder(y):
+        return x + y
+
+    return adder
+
+
+add_10 = create_adder(10)
+add_10(3)  # => 13
+
+# Також є і анонімні функції
+(lambda x: x > 2)(3)  # => True
+(lambda x, y: x ** 2 + y ** 2)(2, 1)  # => 5
+
+# Присутні вбудовані функції вищого порядку
+map(add_10, [1, 2, 3])  # => [11, 12, 13]
+map(max, [1, 2, 3], [4, 2, 1])  # => [4, 2, 3]
+
+filter(lambda x: x > 5, [3, 4, 5, 6, 7])  # => [6, 7]
+
+# Для зручного відображення і фільтрації можна використовувати 
+# включення у вигляді списків
+[add_10(i) for i in [1, 2, 3]]  # => [11, 12, 13]
+[x for x in [3, 4, 5, 6, 7] if x > 5]  # => [6, 7]
+
+# Ви також можете скористатися включеннями множин та словників
+{x for x in 'abcddeef' if x in 'abc'}  # => {'a', 'b', 'c'}
+{x: x ** 2 for x in range(5)}  # => {0: 0, 1: 1, 2: 4, 3: 9, 4: 16}
+
+
+####################################################
+## 5. Класи
+####################################################
+
+# Аби отримати клас, ми наслідуємо object.
+class Human(object):
+    # Атрибут класу. Він розділяється всіма екземплярами цього класу.
+    species = "H. sapiens"
+
+    # Звичайний конструктор, буде викликаний при ініціалізації екземпляру класу
+    # Зверніть увагу, що подвійне підкреслення на початку та наприкінці імені
+    # використовується для позначення об'єктів та атрибутів,
+    # які використовуються Python, але знаходяться у просторах імен, 
+    # якими керує користувач. Не варто вигадувати для них імена самостійно.
+    def __init__(self, name):
+        # Присвоєння значення аргумента атрибуту класу name
+        self.name = name
+
+        # Ініціалізуємо властивість
+        self.age = 0
+
+    # Метод екземпляру. Всі методи приймають self у якості першого аргументу
+    def say(self, msg):
+       return "%s: %s" % (self.name, msg)
+
+    # Методи класу розділяються між усіма екземплярами
+    # Вони викликаються з вказанням викликаючого класу 
+    # у якості першого аргументу
+    @classmethod
+    def get_species(cls):
+        return cls.species
+
+    # Статичний метод викликається без посилання на клас або екземпляр
+    @staticmethod
+    def grunt():
+        return "*grunt*"
+
+    # Властивість.
+    # Перетворює метод age() в атрибут тільки для читання
+    # з таким же ім'ям.
+    @property
+    def age(self):
+        return self._age
+
+    # Це дозволяє змінювати значення властивості
+    @age.setter
+    def age(self, age):
+        self._age = age
+
+    # Це дозволяє видаляти властивість
+    @age.deleter
+    def age(self):
+        del self._age
+
+
+# Створюємо екземпляр класу
+i = Human(name="Данило")
+print(i.say("привіт"))  # Друкує: «Данило: привіт»
+
+j = Human("Меланка")
+print(j.say("Привіт"))  # Друкує: «Меланка: привіт»
+
+# Виклик методу класу
+i.get_species()  # => "H. sapiens"
+
+# Зміна розділюваного атрибуту
+Human.species = "H. neanderthalensis"
+i.get_species()  # => "H. neanderthalensis"
+j.get_species()  # => "H. neanderthalensis"
+
+# Виклик статичного методу
+Human.grunt()  # => "*grunt*"
+
+# Оновлюємо властивість
+i.age = 42
+
+# Отримуємо значення
+i.age  # => 42
+
+# Видаляємо властивість
+del i.age
+i.age  # => виникає помилка атрибуту
+
+####################################################
+## 6. Модулі
+####################################################
+
+# Ви можете імпортувати модулі
+import math
+
+print(math.sqrt(16))  # => 4
+
+# Ви можете імпортувати окремі функції з модуля
+from math import ceil, floor
+
+print(ceil(3.7))  # => 4.0
+print(floor(3.7))  # => 3.0
+
+# Можете імпортувати всі функції модуля.
+# Попередження: краще так не робіть
+from math import *
+
+# Можете скорочувати імена модулів
+import math as m
+
+math.sqrt(16) == m.sqrt(16)  # => True
+# Ви також можете переконатися, що функції еквівалентні
+from math import sqrt
+
+math.sqrt == m.sqrt == sqrt  # => True
+
+# Модулі в Python — це звичайні Python-файли. Ви
+# можете писати свої модулі та імпортувати їх. Назва
+# модуля співпадає з назвою файлу.
+
+# Ви можете дізнатися, які функції та атрибути визначені
+# в модулі
+import math
+
+dir(math)
+
+
+# Якщо у вас є Python скрипт з назвою math.py у тій же папці, що
+# і ваш поточний скрипт, то файл math.py
+# може бути завантажено замість вбудованого у Python модуля.
+# Так трапляється, оскільки локальна папка має перевагу
+# над вбудованими у Python бібліотеками.
+
+####################################################
+## 7. Додатково
+####################################################
+
+# Генератори
+# Генератор "генерує" значення тоді, коли вони запитуються, замість того, 
+# щоб зберігати все одразу
+
+# Метод нижче (*НЕ* генератор) подвоює всі значення і зберігає їх 
+# в `double_arr`. При великих розмірах може знадобитися багато ресурсів!
+def double_numbers(iterable):
+    double_arr = []
+    for i in iterable:
+        double_arr.append(i + i)
+    return double_arr
+
+
+# Тут ми спочатку подвоюємо всі значення, потім повертаємо їх,
+# аби перевірити умову
+for value in double_numbers(range(1000000)):  # `test_non_generator`
+    print value
+    if value > 5:
+        break
+
+
+# Натомість ми можемо скористатися генератором, аби "згенерувати"
+# подвійне значення, як тільки воно буде запитане
+def double_numbers_generator(iterable):
+    for i in iterable:
+        yield i + i
+
+
+# Той самий код, але вже з генератором, тепер дозволяє нам пройтися по
+# значенням і подвоювати їх одне за одним якраз тоді, коли вони обробляються
+# за нашою логікою, одне за одним. А як тільки ми бачимо, що value > 5, ми
+# виходимо з циклу і більше не подвоюємо більшість значень, 
+# які отримали на вхід (НАБАГАТО ШВИДШЕ!)
+for value in double_numbers_generator(xrange(1000000)):  # `test_generator`
+    print value
+    if value > 5:
+        break
+
+# Між іншим: ви помітили використання `range` у `test_non_generator` і 
+# `xrange` у `test_generator`?
+# Як `double_numbers_generator` є версією-генератором `double_numbers`, так
+# і `xrange` є аналогом `range`, але у вигляді генератора.
+# `range` поверне нам масив з 1000000 значень
+# `xrange`, у свою чергу, згенерує 1000000 значень для нас тоді, 
+# коли ми їх запитуємо / будемо проходитись по ним.
+
+# Аналогічно включенням у вигляді списків, ви можете створювати включення
+# у вигляді генераторів.
+values = (-x for x in [1, 2, 3, 4, 5])
+for x in values:
+    print(x)  # друкує -1 -2 -3 -4 -5
+
+# Включення у вигляді генератора можна явно перетворити у список
+values = (-x for x in [1, 2, 3, 4, 5])
+gen_to_list = list(values)
+print(gen_to_list)  # => [-1, -2, -3, -4, -5]
+
+# Декоратори
+# Декоратор – це функція вищого порядку, яка приймає та повертає функцію.
+# Простий приклад використання – декоратор add_apples додає елемент 'Apple' в
+# список fruits, який повертає цільова функція get_fruits.
+def add_apples(func):
+    def get_fruits():
+        fruits = func()
+        fruits.append('Apple')
+        return fruits
+    return get_fruits
+
+@add_apples
+def get_fruits():
+    return ['Banana', 'Mango', 'Orange']
+
+# Друкуємо список разом з елементом 'Apple', який знаходиться в ньому:
+# Banana, Mango, Orange, Apple
+print ', '.join(get_fruits())
+
+# У цьому прикладі beg обертає say
+# Beg викличе say. Якщо say_please дорівнюватиме True, то повідомлення,
+# що повертається, буде змінено.
+from functools import wraps
+
+
+def beg(target_function):
+    @wraps(target_function)
+    def wrapper(*args, **kwargs):
+        msg, say_please = target_function(*args, **kwargs)
+        if say_please:
+            return "{} {}".format(msg, "Будь ласка! Я бідний :(")
+        return msg
+
+    return wrapper
+
+
+@beg
+def say(say_please=False):
+    msg = "Ви можете купити мені пива?"
+    return msg, say_please
+
+
+print say()  # Ви можете купити мені пива?
+print say(say_please=True)  # Ви можете купити мені пива? Будь ласка! Я бідний :(
+```
+
+## Готові до більшого?
+
+### Безкоштовні онлайн-матеріали
+
+* [Learn Python The Hard Way](http://learnpythonthehardway.org/book/)
+* [Dive Into Python](http://www.diveintopython.net/)
+* [Официальная документация](http://docs.python.org/2.6/)
+* [Hitchhiker's Guide to Python](http://docs.python-guide.org/en/latest/)
+* [Python Module of the Week](http://pymotw.com/2/)
+* [A Crash Course in Python for Scientists](http://nbviewer.ipython.org/5920182)
+
+### Платні
+
+* [Programming Python](http://www.amazon.com/gp/product/0596158106/ref=as_li_qf_sp_asin_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596158106&linkCode=as2&tag=homebits04-20)
+* [Dive Into Python](http://www.amazon.com/gp/product/1441413022/ref=as_li_tf_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1441413022&linkCode=as2&tag=homebits04-20)
+* [Python Essential Reference](http://www.amazon.com/gp/product/0672329786/ref=as_li_tf_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0672329786&linkCode=as2&tag=homebits04-20)
+

visualbasic.html.markdown

@@ -5,7 +5,7 @@ contributors:
 filename: learnvisualbasic.vb
 ---
 
-```vbnet
+```
 Module Module1
 
     Sub Main()

zh-cn/c-cn.html.markdown

@@ -41,7 +41,7 @@ enum days {SUN = 1, MON, TUE, WED, THU, FRI, SAT};
 void function_1(char c);
 void function_2(void);
 
-// 如果函数出现在main()之后，那么必须在main()之前
+// 如果函数调用在main()之后，那么必须在main()之前
 // 先声明一个函数原型
 int add_two_ints(int x1, int x2); // 函数原型
 

zh-cn/visualbasic-cn.html.markdown

@@ -8,7 +8,7 @@ lang: zh-cn
 filename: learnvisualbasic-cn.vb
 ---
 
-```vbnet
+```
 Module Module1
 
     Sub Main()