From: cbare <christopherbare@...>
Date: 2008-05-22T14:00:04+09:00
Subject: Why does returning from a block cause a LocalJumpError

Hi Ruby gurus,

I'm hoping someone can set me straight about something. Take the
following lines of Ruby and output from the interpreter:

[1,2,3].map {|a| a*a}
>> [1,4,9]

[4,5,6].map {|a| return a*a}
>> LocalJumpError: unexpected return

I'm trying to fit Ruby's code blocks in with the concept of anonymous
functions that's in my brain from languages like Scheme. It seems that
a code block must be something a little different, because returning
from an anonymous function should be a fine thing to do. Does a code
block not create an environment for local variables on the stack? What
is a LocalJump anyway?

I'm sure this is addressed elsewhere, but thanks for any clues or
pointers,

-chris