From: John Carter <john.carter@...>
Date: 2010-08-26T08:51:58+09:00
Subject: Some odd ball optimization tricks....

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Here are two idioms which you may find useful, or at least curious, when
trying to optimize the heck out of a Ruby script....

require 'pp'

# Similar to the "autosequence" facility in SQL.
# Useful for replacing a complex key with a very simply POD proxy object.
file_sequence = 0
file_index = Hash.new{|hash,key| file_sequence+=1;hash[key] = file_sequence}


p file_index["foo"]
p file_index["foo"]
p file_index["bah"]
p file_index["foo"]
p file_index["bah"]
pp file_index


# Similar to "to_sym", but can cope with spaces and weird characters...
# So if tom1, tom2, tom3... go out of scope they can be garbage collected...
# so if you end up just holding tomtom, you have only one copy of "tom" and
you can test for
# equality with .object_id == .object_id!
one_true_string = Hash.new{|hash,string| hash[string] = string}

tom1 = "tom"
tom2 = "tom"
tom3 = "#{tom1}"
tom4 = tom2.clone
tom5 = "t"+"o"+"m"

toms = [tom1, tom2, tom3, tom4, tom5]

pp toms
pp toms.collect{|tom| tom.object_id }
tomtom = toms.collect{|tom| one_true_string[tom] }
pp tomtom
pp tomtom.collect{|tom| tom.object_id }

Running the above results in...
1
1
2
1
2
{"foo"=>1, "bah"=>2}
["tom", "tom", "tom", "tom", "tom"]
[-609503848, -609503908, -609503888, -609503918, -609503978]
["tom", "tom", "tom", "tom", "tom"]
[-609503848, -609503848, -609503848, -609503848, -609503848]

-- 
John Carter                             Phone : (64)(3) 358 6639
Tait Electronics                        Fax   : (64)(3) 359 4632
PO Box 1645 Christchurch                Email : john.carter@taitradio.com
New Zealand

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