Storing Regex in a constant instead of a method saves a lot of memory, but not a lot of time.

gistfile1.txt

?> def get_memory_usage
>>   `ps -o rss= -p #{Process.pid}`.to_i
>> end
=> nil
>> 
?> before = get_memory_usage
=> 20296
>> 
?> n.times {MethodRegexObject.new}

=> 5000000
>> 
?> after = get_memory_usage
=> 23484
>> print "Method Regex Usage: " + (after-before).to_s
Method Regex Usage: 3188=> nil
>> 
?> before = get_memory_usage
=> 23484
>> 
?> n.times {ConstantRegexObject.new}
=> 5000000
>> 
?> after = get_memory_usage
=> 24208
>> print "Constant Regex Usage: " + (after-before).to_s
Constant Regex Usage: 724=> nil

?> 
?> Benchmark.bmbm do |x|
?>   x.report("Method") { n.times {MethodRegexObject.new} }
>>   x.report("Constant") { n.times {ConstantRegexObject.new} }
>> 
?> end

Rehearsal --------------------------------------------
Method    17.080000   0.070000  17.150000 ( 17.155665)
Constant  16.750000   0.120000  16.870000 ( 16.867394)
---------------------------------- total: 34.020000sec

               user     system      total        real
Method    17.120000   0.350000  17.470000 ( 17.470644)
Constant  16.700000   0.300000  17.000000 ( 17.007322)