From: mental@...
Date: 2006-01-05T02:24:48+09:00
Subject: Re: More on the fundamentals...

Quoting John Maclean <info@jayeola.org>:

> In this line of code can anyone tell me why "food" is a method? I
> thought that they are preceded by a dot.
>
>     __  an array           __ the method   __ parameters for code
> block
>    /                      /               /
>   [cornflakes, yam, rice].each { |food| eat food}
>                                /   \
>               code block    __/     \__block args
>

Within the context of the block, "food" is a variable.  "eat",
however, will be interpreted as a private method call (i.e. as a
call to the "eat" method on self), provided an "eat" variable does
not already exist in that scope.

Generally, given a bare identifier, the rule is:

 1. If a previous assignment to the name exists in the current scope
(whether or not it was actually performed), the name is a variable
(or a parse error if you try to give it parameters)

 2. otherwise, it is a call to a private method on self

Examples:

 1. foo # method

 2. foo = 1
    foo # variable

 3. if false
      foo = 1 # never executed
    end
    foo # still a variable (initialized to nil)

 4. [1, 2, 3].each { |foo| # introduced as block param
      foo # variable here
    }
    foo # method call here

 5. foo = 1
    foo # variable
    [1, 2, 3].each { |foo| # same variable
      foo # yes, same variable
    }
    foo # still same variable

-mental