From: "mame (Yusuke Endoh)" <mame@...>
Date: 2012-11-20T02:44:54+09:00
Subject: [ruby-core:49593] [ruby-trunk - Feature #6376][Assigned] Feature lookup and checking if feature is loaded


Issue #6376 has been updated by mame (Yusuke Endoh).

Status changed from Feedback to Assigned
Target version changed from 2.0.0 to next minor

If I had a right to judge a feature request, I would reject this.
But actually I have no right.  Assigning to matz. (virtual rejection?)

I don't see what OP really want to do.  Doesn't Rescue'ing a LoadError from require help?

  begin
    require "foo"
    FooExist = true
  rescue LoadError
    FooExist = false
  end

A dirty operation should be performed by a dirty code.

-- 
Yusuke Endoh <mame@tsg.ne.jp>
----------------------------------------
Feature #6376: Feature lookup and checking if feature is loaded
https://bugs.ruby-lang.org/issues/6376#change-33107

Author: trans (Thomas Sawyer)
Status: Assigned
Priority: Normal
Assignee: mame (Yusuke Endoh)
Category: core
Target version: next minor


$LOADED_FEATURES is useful to know what "files" have been loaded. But it doesn't really tell us what "features" have been loaded. If there where were a way to look-up a load path, without actually loading it then it would be possible to compare that to $LOADED_FEATURES and thus know. e.g.

    require 'ostruct'
    $LOADED_FEATURES #=> [..., "/home/trans/.local/lib/ry/rubies/1.9.3-p125/lib/ruby/1.9.1/ostruct.rb"]

    path = require_path('ostruct') #=> "/home/trans/.local/lib/ry/rubies/1.9.3-p125/lib/ruby/1.9.1/ostruct.rb"
    $LOADED_FEATURES.include?(path)

Of course, it would be nice to also have:

    required?('ostruct')  #=> true

These methods could be class methods of special module, if it's important to keep the Kernel more tidy, e.g. `Ruby.required?('ostruct')`.

I am currently working on a project where I need this (and have a couple of other projects that could use it too) and I've had to implement the whole thing from scratch, which isn't simple, nor fast, nor am I 100% confident that it specs exactly to Ruby's own lookup procedure. So it would be much better if Ruby would expose its lookup functionality.




-- 
http://bugs.ruby-lang.org/