From: matz@... (Yukihiro Matsumoto)
Date: 2002-02-19T13:21:31+09:00
Subject: Re: Problems with Ruby in C

Hi,

In message "Problems with Ruby in C"
    on 02/02/18, Joakim Andersson <tyrak@borgship.net> writes:

|The Ruby program does what is expected but the C program doesn't, so I'm
|hoping that some kind soul could tell me what I'm doing wrong.

Ah, first of all, local variables does not belong to any object, so
that in the following code:

|class Context
|  def execute(str)
|    instance_eval(str)
|  end
|end
|
|a = Context.new()
|a.execute("a = 5 ; puts a")

the assignemnt to the variable a is done in the scope of the execute
method, whic vaporized every time execute called.  On the other hand,

|static VALUE cContext_execute(VALUE self, VALUE str)
|{
|    return rb_funcall(self, rb_intern("instance_eval"), 1, str);
|}

this case, the assignment is done at the toplevel scope, which is used
again and again.  That's the difference.

							matz.