From: ts <decoux@...>
Date: 2001-09-24T19:38:52+09:00
Subject: [ruby-talk:21626] Re: C++ / Ruby questions again

>>>>> "B" == =?ISO-8859-1?Q?Bernhard Gl=FCck?= <jglueck@vol.at> writes:

B> Now my only help would be a method or other way like rb_respond_to  to
B> check wether a method needs a parameter and if yes how many.. so that
B> i only call it when it has the appropriate paramter count.. Is there a
B> way to do this ?

 #arity must give what you want with a Proc, or a Method object

B> Second, i askes about how to catch all ruby exceptions.. I think i did
B> not state clearly what i wanted, i already used rb_eval_string_protect
B> for code evaluation.. so no crashes happened.. but If e.g a ruby
B> program throws a string exception i want to present that string to the
B> user of my program... so is there a way to intercept exceptions check
B> if they have a presentable data type and display it ? without
B> interupting program flow ? Maybe with a callback function ?

 Well, rb_eval_string_protect() return in the parameter state the error
 code. This mean that you can write something like this (not tested) 

   state = 0;
   result = rb_eval_string_protect(string, &state);
   if (state) {
      VALUE error = rb_inspect(rb_gv_get("$!"));
      /* do what you want with error, it's a String VALUE */
   }


Guy Decoux