This post originated from an RSS feed registered with Ruby Buzz by Eigen Class. Original Post: Using introspection to get method arguments and other info Feed Title: Eigenclass Feed URL: http://feeds.feedburner.com/eigenclass Feed Description: Ruby stuff --- trying to stay away from triviality. Latest Ruby Buzz Posts Latest Ruby Buzz Posts by Eigen Class Latest Posts From Eigenclass

I just wrote a small script that uses introspection to tell you the methods defined in a file plus their argument names and default values. It's a quick hack, but it works surprisingly well.

Here are some examples:

   $ ruby -rmethod_args -rcsv -e1
   CSV::Cell#initialize (data = "", is_null = false)
   CSV::Cell#data ()
   CSV.open (path, mode, fs = nil, rs = nil)
   CSV.foreach (path, rs = nil)
   CSV.read (path, length = nil, offset = nil)
   [...]

method_args.rb can detect arguments with default values and "splat args":

   $ ruby -rmethod_args -rbenchmark -e1
   Benchmark#benchmark (caption = "", label_width = nil, fmtstr = nil, *labels)
   Benchmark#bm (label_width = 0, *labels)
   Benchmark#bmbm (width = 0)
   Benchmark#measure (label = "")
   [...]

The nice thing is that method_args.rb actually requires your library code and will take into account its dependencies too. So it'll tell you all the methods you'd pull into your runtime if you required some file.

At the time being, all this script does is writing the methods it found on stdout, but it could for instance send them to another application through a socket to provide fairly accurate intellisense information, or generate rich tags, or...