From: Robert Klemme <bob.news@...>
Date: 2004-04-30T22:44:00+09:00
Subject: Re: File.expand_path(__FILE__)


"Simon Strandgaard" <neoneye@adslhome.dk> schrieb im Newsbeitrag
news:20040430134446.7d4d3fc1.neoneye@adslhome.dk...
> "Robert Klemme" <bob.news@gmx.net> wrote:
> > "Simon Strandgaard" <neoneye@adslhome.dk> schrieb im Newsbeitrag
> > news:20040430124420.2f2b621b.neoneye@adslhome.dk...
> > > "Robert Klemme" <bob.news@gmx.net> wrote:
> > > > "Simon Strandgaard" <neoneye@adslhome.dk> schrieb im Newsbeitrag
> > > > >
> > > > > Maybe extend __FILE__ with a #absolute  method,
> > > > > in order to make __FILE__ immune against chdir ?
> > > >
> > > > This is easily fixed:
> > > >
> > > > FILE = File.expand_path __FILE__
> > > > p [__FILE__, FILE]
> > >
> > > Not if the person has done a chdir just before expand_path.
> >
> > Well, I should've written "first line in script".
>
> ok ;-)
>
>
> > > I wonder why __FILE__ isn't an absolute path. Relative paths is
> > > just too fragile.
> > >
> > >
> > > Proposal:  make __FILE__ an absolute path.
> > > That would make __FILE__ robust to Dir.chdir.
> > >
> > >
> > > Any thoughts on this proposal?   fore or against
> >
> > Slightly against, because
> >
> > - it's easily fixed
>
> Agree.. however see below
>
>
> > - you loose information: there might be situations where the script
wants
> > to know the exact path it was invoked with.
>
> I think its the wrong place to retrive this kind of information.
> Broken metaphor... I have used it myself, but without thinking about it.

Where would you expect it to reside?  Maybe the best solution is

$0      : path as used for invocation
__FILE__: abs path to current file

Then I agree. :-)  Any objections?  Does this break existing code?

> > - most of the time (when invoked from the shell via path expansion)
> > scripts are invoked with an absolute path anyway.
>
> Please elaborate.. I don't understand.
>
> :-)

15:35:31 [ContentReporter_BRANCH]: PATH="${PATH}:/c/temp/ruby" bash -c
'echo $PATH; dollar0.rb'
<privacy>:/c/temp/ruby
__FILE=/c/temp/ruby/dollar0.rb
$0=/c/temp/ruby/dollar0.rb
15:35:51 [ContentReporter_BRANCH]: cat /c/temp/ruby/dollar0.rb
#!/usr/bin/ruby

puts "__FILE=#{__FILE__}"
puts "$0=#{$0}"

The invocation (-c 'dollar0.rb') does not use a path but rather the shell
finds the executable based on its $PATH.

Regards

    robert