From: Rodrigo Rosenfeld Rosas <rr.rosas@...>
Date: 2011-06-07T20:15:21+09:00
Subject: [ruby-core:36815] Re: [Ruby 1.9 - Feature #4840][Open] Allow returning from require

Em 07-06-2011 07:10, Yusuke ENDOH escreveu:
> Hello,
>
> 2011/6/6 Rodrigo Rosenfeld Rosas<rr.rosas@gmail.com>:
>> I have a situation where there is some code in Gitorious like:
>>
>> unless defined? GitoriousConfig
>>   # tons of lines here
>> end
>>
>> And I would it to look like
>>
>> return if defined? GitoriousConfig
>>
>> #tons of lines here
>>
>> It would be great to allow return from a required file or some other keyword (break, etc or a new one)
>
> Agreed.  It would be also useful to write platform-specific code:
>
>    require "test/unit"
>
>    return unless /mswin|cygwin|mingw|bccwin/ =~ RUBY_PLATFORM
>
>    class TestForWindowsEnv<  Test::Unit::TestCase
>    ...
>
>
> Here is an experimental patch:
>
>
> diff --git a/compile.c b/compile.c
> index 10d63bc..7b9c490 100644
> --- a/compile.c
> +++ b/compile.c
> @@ -4291,10 +4291,6 @@ iseq_compile_each(rb_iseq_t *iseq, LINK_ANCHOR
> *ret, NODE * node, int poped)
>   	rb_iseq_t *is = iseq;
>
>   	if (is) {
> -	    if (is->type == ISEQ_TYPE_TOP) {
> -		COMPILE_ERROR((ERROR_ARGS "Invalid return"));
> -	    }
> -	    else {
>   		LABEL *splabel = 0;
>
>   		if (is->type == ISEQ_TYPE_METHOD) {
> @@ -4321,7 +4317,6 @@ iseq_compile_each(rb_iseq_t *iseq, LINK_ANCHOR
> *ret, NODE * node, int poped)
>   			ADD_INSN(ret, nd_line(node), pop);
>   		    }
>   		}
> -	    }
>   	}
>   	break;
>         }
> diff --git a/vm_insnhelper.c b/vm_insnhelper.c
> index f40dfdf..274f45d 100644
> --- a/vm_insnhelper.c
> +++ b/vm_insnhelper.c
> @@ -1561,8 +1561,6 @@ vm_throw(rb_thread_t *th, rb_control_frame_t *reg_cfp,
>   		    cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
>   		}
>
> -		rb_vm_localjump_error("unexpected return", throwobj, TAG_RETURN);
> -
>   	      valid_return:
>   		pt = dfp;
>   	    }
>

This patch is so small, that it seems strange that it affects only 
requires... Won't it have side effects? Notice that I didn't test it yet.

I agree with you about specific-platform tests use case too.

Thanks for your interest,

Rodrigo.