From: "Chr. Rippel" <chr_news@...>
Date: 2002-01-31T09:44:52+09:00
Subject: Re: Proc hash bug?


<ntalbott@rolemodelsoft.com> wrote in 

> But that's one of the things I love most about Ruby! The 'method { block
> }' syntax is very pleasing to me, so it makes me ask questions when it
> doesn't work for my application. At this point, I'm just trying to
> understand why the behavior is as it is, and not the way I expect.
 ... I can see that
> 
....
> Ah, yes, I thought about this. I might end up doing it, or something
> like it that uses a wrapper instead of modifying Proc itself. Is there a
> more direct way to access the id than using a regular expression?

Well looking at the source in eval.c  6567-82

static VALUE
proc_to_s(self, other)
    VALUE self, other;
{
    struct BLOCK *data;
    char *cname = rb_class2name(CLASS_OF(self));
    VALUE str;

    Data_Get_Struct(self, struct BLOCK, data);
    str = rb_str_new(0, strlen(cname)+6+16+1); /* 6:tags 16:addr 1:nul */
    sprintf(RSTRING(str)->ptr, "#<%s:0x%lx>", cname, data->tag);
    RSTRING(str)->len = strlen(RSTRING(str)->ptr);
    if (OBJ_TAINTED(self)) OBJ_TAINT(str);

    return str;
}

it should not be hard to write this as an extension - actually its probably
not such bad idea to write up an RCR (there was a similar situation about
#== I believe) . Using data->tag as a hash value seems save to me - anyway
for now you also could(should) write 

class Proc
    alias :eql? :==
    def hash
        inspect.sub(/^(#<type.to_s:)/){''}.sub(/(>)$/){''}.to_i(16)
    end
end

/Christoph