From: Gavin Kistner <gavin@...>
Date: 2004-02-20T23:14:54+09:00
Subject: Re: proposal: let kind_of take more arguments

Gavin Kistner wrote:

> nobu.nokada@softhome.net wrote:
> 
>>     unless [Zero, One].any? {|klass| choice.kind_of?(klass)}
>>
>> Or shorter
>>
>>     unless [Zero, One].any?(&choice.method(:kind_of?)
> 
> 
> Or, as I noted on the RCR:
> 
>       unless ([Zero,One] & choice.class.ancestors).length>0
> 

For the curious, here's how the three methods above stack up in terms of 
performance (see below stupid test code that should probably be using 
Ruby's built-in profiling for the results). The summary is: The third 
method above is generally faster, unless there's a high probability that 
a match will be found early on in your test list, in which case the 
first example above is fastest.


-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_

instance  =  ValidForm::Text.new('userName');
testList = [
	{:classes =>
		[Array,ValidForm::OptionSet,Module,Method,Fixnum],
		:name=>'No match is found:'},
	{:classes =>
		[Array,ValidForm::OptionSet,Module,Method,Object],
		:name=>'Match at end of list:'},
	{:classes =>
		[Object,Array,ValidForm::OptionSet,Module,Method],
		:name=>'Match at start of list:'}
	]

n=50000

puts instance.class.ancestors.join(',')

testList.each{ |test|
	classes=test[:classes]
	puts test[:name]
	s1 = Time.now
	n.times{
		(classes & instance.class.ancestors).length>0
	}
	s2 = Time.now
	printf "Using set intersection: %.2f\n",(s2-s1)
	
	
	s1 = Time.now
	n.times{
		classes.any?{ |k| instance.kind_of?(k) }
	}
	s2 = Time.now
	printf "  Using explicit block: %.2f\n",(s2-s1)
	
	s1 = Time.now
	n.times{
		classes.any?(&instance.method(:kind_of?))
	}
	s2 = Time.now
	printf "Passing kind_of? block: %.2f\n",(s2-s1)
	puts
}

OUTPUTS

ValidForm::Text,ValidForm::Field,Object,Kernel

No match is found:
Using set intersection: 1.17
   Using explicit block: 1.38
Passing kind_of? block: 2.24

Match at end of list:
Using set intersection: 1.18
   Using explicit block: 1.21
Passing kind_of? block: 2.27

Match at start of list:
Using set intersection: 1.19
   Using explicit block: 0.46
Passing kind_of? block: 1.26


-- 
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