From: "Mauricio Fernández" <batsman.geo@...>
Date: 2004-07-03T08:28:51+09:00
Subject: Re: slow method searching?

On Sat, Jul 03, 2004 at 08:02:57AM +0900, Mauricio Fern�ndez wrote:
> > Why does it take longer and longer for Ruby to throw NoMethodError for 
> > large arrays? What is going on here? This happens with hash too.
> 
> When the exception is printed, a string representation of the associated
> object is created by calling #inspect. See name_err_mesg_to_str in
> error.c:
[...]
> BTW, one oddity in the implementation: ruby uses internally a constant
> named "message" (lower case), which you cannot access from Ruby neither as
> NameError::message nor with NameError.const_get("message"), however
> 
> >> ObjectSpace.each_object(Class){|x| p x if x.ancestors.include? Data}
> NameError::message
> Data

Just for a laugh, here's some additional confirmation of the above:

batsman@tux-chan:/tmp$ cat dfghdfg.rb
def test_exc(code)
    s = Time.new
    eval code
rescue NameError
    puts "Eval: #{code}"
    puts "Message: #{$!.message}"
    puts "Took #{Time.new-s} seconds."
end

test_exc %{ a=(1..400000).to_a; a.classx }
test_exc %{ a=(1..400000).to_a; b=[]; b.classx }

puts "=" * 80
puts "Redefining #to_str for exception messages..."
puts

klass = nil
ObjectSpace.each_object(Class){|c| klass = c if c.ancestors.include?(Data) && c!= Data}
klass.send(:define_method, :to_str) { "booooo spooky NameError" }

test_exc %{ a=(1..400000).to_a; a.classx }
test_exc %{ a=(1..400000).to_a; b=[]; b.classx }

batsman@tux-chan:/tmp$ ruby dfghdfg.rb
Eval:  a=(1..400000).to_a; a.classx
Message: undefined method `classx' for #<Array:0x401c941c>
Took 1.691099 seconds.
Eval:  a=(1..400000).to_a; b=[]; b.classx
Message: undefined method `classx' for []:Array
Took 0.106893 seconds.
================================================================================
Redefining #to_str for exception messages...

Eval:  a=(1..400000).to_a; a.classx
Message: booooo spooky NameError
Took 0.115443 seconds.
Eval:  a=(1..400000).to_a; b=[]; b.classx
Message: booooo spooky NameError
Took 0.110813 seconds.


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