From ruby-talk  Mon Feb 02 07:42:08 2004
From: Emmanuel Touzery <emmanuel.touzery () wanadoo ! fr>
Date: Mon, 02 Feb 2004 07:42:08 +0000
To: ruby-talk
Subject: Re: Method Reflection
Message-Id: <401DFFE2.9060002 () wanadoo ! fr>
X-MARC-Message: https://marc.info/?l=ruby-talk&m=107570778422735

Benedikt Huber wrote:

>I'm quite new to ruby and was amazed by the powerful reflection
>mechanism, so tried to use the tracing function to analyse the object
>space of our project.
>
>It was amazingly easy to dump module,class and method definitions to xml
>as they occured, but i was not able to retrieve any information about
>the formal method parameters (correct term?), neither the number nor the
>name.
>  
>
http://www.rubycentral.com/book/ref_c_method.html

arity gives the number of parameters (check the special cases in the doc 
with method with variable number of parameters -with optional parameters-).

irb(main):001:0> a = String.new
=> ""
irb(main):002:0> a.method('split').arity
=> -1
irb(main):004:0> a.method('insert').arity
=> 2

i'm afraid you can't get the name of the parameters at runtime (this is 
a job for rdoc).

>I wasn't able to retrieve information on instance variables as
>well. Is it possible ?

Apparently there is a instance_variables method.

emmanuel