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Add clarification on bind / match with = op in erlang. Fixes #1139
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@@ -25,6 +25,7 @@ filename: learnerlang.erl
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%% 1. Variables and pattern matching.
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%% 1. Variables and pattern matching.
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% In Erlang new variables are bound with an `=` statement.
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Num = 42. % All variable names must start with an uppercase letter.
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Num = 42. % All variable names must start with an uppercase letter.
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% Erlang has single-assignment variables; if you try to assign a different
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% Erlang has single-assignment variables; if you try to assign a different
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@@ -32,9 +33,11 @@ Num = 42. % All variable names must start with an uppercase letter.
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Num = 43. % ** exception error: no match of right hand side value 43
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Num = 43. % ** exception error: no match of right hand side value 43
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% In most languages, `=` denotes an assignment statement. In Erlang, however,
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% In most languages, `=` denotes an assignment statement. In Erlang, however,
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% `=` denotes a pattern-matching operation. `Lhs = Rhs` really means this:
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% `=` denotes a pattern-matching operation. When an empty variable is used on the
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% evaluate the right side (`Rhs`), and then match the result against the
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% left hand side of the `=` operator to is bound (assigned), but when a bound
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% pattern on the left side (`Lhs`).
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% varaible is used on the left hand side the following behaviour is observed.
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% `Lhs = Rhs` really means this: evaluate the right side (`Rhs`), and then
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% match the result against the pattern on the left side (`Lhs`).
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Num = 7 * 6.
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Num = 7 * 6.
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% Floating-point number.
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% Floating-point number.
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