Use Ruby implementation for which

[davispuh]

In Windows there's no /dev/null and it causes error "The System cannot find the path specified". Also in Windows there's no native which and it works only because it's included in DevKit.

This Ruby implementation should correctly work for all platforms.

[larskanis]

Thanks for your contributions! I'll find some time at the weekend to inspect your requests.

[larskanis]

The output "The System cannot find the path specified" appears for every rake run, but does not break the build if make is called make on the system, which is the case for the Windows RubyInstaller. Nevertheless it's misleading to have such an output.

I think this is a proper cross platform solution, that should be merged.

[davispuh]

I just rebased (just in case) and that previous Travis failure was due something else.

[davispuh]

rebased again, why this haven't been merged?

[djberg96]

Please merge.

[tduehr]

Why iterate over the path and extensions rather than use a glob?

[djberg96]

@tduehr wouldn't work on Windows with their file extensions, e.g. notepad.exe, not notepad.

[tduehr]

Dir.glob("*.{exe,bat}") works for me in 2.2.2 (compiled w/ VC) under win8.1. C:\Ruby\bin

Dir.glob("**/*{#{ENV["PATHEXT"].tr(';',',')}}") works in the directory above it C:\Ruby

[djberg96]

Hm, for some reason I thought that approach had some issue, but perhaps I'm mistaken. Anyway, it's not like we need to hyper optimize for this little bit of functionality. I'm happy with whatever works. :)

[davispuh]

I'm don't really understand why glob would be preferable? I'm not sure if there would be any performance benefits.
Here's implementation using Dir.glob and it seems to be more complicated...

def which(name)
  exts = ENV['PATHEXT'] ? '{' + ENV['PATHEXT'].split(';').join(',') + '}' : ''
  paths = '{' + ENV['PATH'].split(File::PATH_SEPARATOR).join(',').gsub('\\', '/') + '}'
  Dir.glob(paths + '/' + name + exts).each do |app|
    return app if File.executable?(app)
  end
  nil
end

In PATH there can be multiple executables with same name and some might not even be executable so we've to check all in correct order.

[tduehr]

I was wondering if there was a specific reason is all... Then i got to way over optimizing. I'll pull this when I get a chance to write something to use which normally then failover to this.