From: Robert Klemme <bob.news@...>
Date: 2004-07-14T18:07:20+09:00
Subject: Re: Printing contents of a method


"Dave Thomas" <dave@pragprog.com> schrieb im Newsbeitrag
news:2F308146-D4FE-11D8-B4D9-000A95676A62@pragprog.com...
>
> On Jul 13, 2004, at 13:43, Nate Smith wrote:
>
> > On Tue, 2004-07-13 at 14:24, Dave Thomas wrote:
> >>>> Does anyone know how to actually print (as a string) the contents
> >>>> of a
> >>>> given method? I've googled and searched books, to no avail. Thanks
> >>>> much
> >>>> for any help
> >>
> >> Might SCRIPT_LINES help? (if the method is loaded into your program
> >> after it starts)
> >
> > Forgive me if I sound stupid, but what is SCRIPT_LINES? I search
google
> > for it and it only came up with Perl references, and a couple of
emails
> > that you wrote which had the word in it. Thanks!
> >
>
> Here's some stuff from the  new pickaxe:
>
> SCRIPT_LINES__ (Hash)
>
> If a constant SCRIPT_LINES__ is defined and references a Hash at the
> time Ruby is compiling code, Ruby will store an entry containing the
> contents of each file it parses, with the file�s name as the key and an
> array of strings as the value. See Kernel.require on page ?? for an
> example.
>
> and then over in Kernel.require:
>
> The SCRIPT_LINES__ constant can be used to capture the source of code
> read using require.
>
> SCRIPT_LINES__ = {}
> require 'code/scriptlines'
> puts "Files: #{SCRIPT_LINES__.keys.join(', ')}"
> SCRIPT_LINES__['./code/scriptlines.rb'].each do |line|
>     puts "Source: #{line}"
> end
>
> produces:
>
> 3/8 Files: ./code/scriptlines.rb,
> /Users/dave/ruby1.8/lib/ruby/1.8/rational.rb
> Source: require 'rational'
> Source:
> Source: puts Rational(1,2)*Rational(3,4)
>
> (where code/scriptlines.rb does indeed contain the three lines of code
> listed above).

But still at best you get the original code of methods when they were
defined.  If someone overrides it, you're lost.  A C extension that can
recreate Ruby from a given method would be a safer approach IMHO.  (If
that's possible, that is.)

Kind regards

    robert