From: Asfand Yar Qazi <ay1204@...2s.com>
Date: 2005-02-18T03:54:52+09:00
Subject: Evaluating a string of Ruby code within an anonymous module: done correctly?

Hi,

I'd like to evaluate a string of Ruby code (stored in a YAML file, as 
it happens) safely.  Note the purpose is simply to avoid variable name 
clashes and stop lots of eval'ed Ruby code from overloading the heap 
with lots of objects (i.e. when the anonymous module is deleted, the 
temporary variables defined within it are also gone.)

The purpose is NOT for safety reasons, so we don't have to worry about 
that.

Am I doing it the right way?  Or does anybody know a better way?  Any 
better way of passing in arguments to the code in the string?

Anyway, here goes:

def eval_string(s, *args_to_pass)
	m = Module.new
	m.const_set("ARGS", arg_to_pass)
	m.class_eval(s.to_str)
end # Soon m will be GC'ed, and all temp objects gone! MUHAHA

s.eval_string(<<EOL, [1, 2, 3, 4, 5])
a = ARGS
b = a.collect {|i| i*3}
c = b.join("||")
puts(c)
EOL



Thanks,
	Asfand Yar