added parse_number

README.md

@@ -40,6 +40,7 @@ Some modules may depend on other modules. For example, the `polyline2d` module d
 	- [rotate_p](https://openhome.cc/eGossip/OpenSCAD/lib-rotate_p.html)
 	- [sub_str](https://openhome.cc/eGossip/OpenSCAD/lib-sub_str.html)
 	- [split_str](https://openhome.cc/eGossip/OpenSCAD/lib-split_str.html)
+	- [parse_number](https://openhome.cc/eGossip/OpenSCAD/lib-parse_number.html)
 	
 - Path
     - [circle_path](https://openhome.cc/eGossip/OpenSCAD/lib-circle_path.html)

docs/lib-parse_number.md

@@ -0,0 +1,12 @@
+# parse_number
+
+Parses the string argument as an number. It depends on the `split_str` and the `sub_str` functions so remember to include split_str.scad and sub_str.scad.
+
+## Parameters
+
+- `t` : A String containing the number representation to be parsed.
+
+## Examples
+
+	echo(parse_number("10") + 1);    // ECHO: 11
+	echo(parse_number("-1.1") + 1);  // ECHO: -0.1

src/parse_number.scad

@@ -0,0 +1,32 @@
+/**
+* parse_number.scad
+*
+* Parses the string argument as an number.
+* It depends on the split_str and the sub_str functions 
+* so remember to include split_str.scad and sub_str.scad.
+* 
+* @copyright Justin Lin, 2017
+* @license https://opensource.org/licenses/lgpl-3.0.html
+*
+* @see https://openhome.cc/eGossip/OpenSCAD/lib-parse_number.html
+*
+**/ 
+    
+function _str_to_int(t, i = 0, mapper = [["0", 0], ["1", 1], ["2", 2], ["3", 3], ["4", 4], ["5", 5], ["6", 6], ["7", 7], ["8", 8], ["9", 9]]) =  
+    i == len(mapper) ? -1 : (
+        mapper[i][0] == t ? mapper[i][1] : _str_to_int(t, i + 1)
+    );
+    
+function _parse_positive_int(t, value = 0, i = 0) =
+    i == len(t) ? value : _parse_positive_int(t, value * pow(10, i) + _str_to_int(t[i]), i + 1);
+
+function _parse_positive_decimal(t, value = 0, i = 0) =
+    i == len(t) ? value : _parse_positive_decimal(t, value + _str_to_int(t[i]) * pow(10, -(i + 1)), i + 1);
+    
+function _parse_positive_number(t) =
+    len(search(".", t)) == 0 ? _parse_positive_int(t) :
+        _parse_positive_int(split_str(t, ".")[0]) + _parse_positive_decimal(split_str(t, ".")[1]);
+         
+function parse_number(t) = 
+    t[0] == "-" ? -_parse_positive_number(sub_str(t, 1, len(t))) : _parse_positive_number(t);
+