From: Tobias Reif <tobiasreif@...>
Date: 2002-01-28T07:10:39+09:00
Subject: Re: how to find out which args a method can take

Mathieu Bouchard wrote:

> On Mon, 28 Jan 2002, Tobias Reif wrote:
> 
>>how can I programmatically find out which objects a certain method can 
>>take if any?
>>
> Congratulations, you just ran into the invisible wall called "paradigm",
> or, in other words, a shared delusion based on a reductionist philosophy.


I know that I can pass wide varieties to some methods. What I thought 
was: perhaps there are any built-in documentation like info bits that 
can help whan generating "tests" for built-in methiods. Something like
Array.works_with_args?('join')    # -> [[String]]
String.works_with_args('sub')     # -> [[Regex,String], [Regex, Block]]
String.works_with_args('reverse') # -> []

((which) do other languages provide such stuff to programs?)

So I could
---
# generate something like
# http://www.pinkjuice.com/txt/methReturnType.rb
# for all built-in classes

class_names = ['String'] #'Array','','','','','','','',''

main_out = []

def make_line obj_name, method
   "puts \"#{method}:\\n \#\{#{obj_name}.#{method}('foo').type\}\"\n"
end

def make_class_tests name
   out = []
   out.push = "# generated!\n"
   obj_name = name[0,1].downcase
   out.push obj_name+' = '+name+'.new(\'foo\')'+"\n"
   eval(name).new('foo').methods.sort.each do |method|
     out.push make_line(obj_name, method)
   end
   out #.split "\n"
end

class_names.each do |name|
   main_out.push make_class_tests(name)
end

puts main_out

open ('array_return_types.rb', 'w') do |file|
   file.write main_out #.split("\n")
end
---

which generates
...
puts "to_a:\n #{s.to_a('foo').type}"
puts "to_f:\n #{s.to_f('foo').type}"
puts "to_i:\n #{s.to_i('foo').type}"
...

Anyways; sunday's over :)


Tobi

-- 
http://www.pinkjuice.com/