Re^2: Parsing named parameters

in reply to Re: Parsing named parameters
in thread Parsing named parameters

As dwildesnl suggested, reversing makes it significantly faster: see benchmark below. But don't do the optimisation unless you need it!

my $data = <DATA>;

use Benchmark "cmpthese";
cmpthese(10_000, {

  "reversed" => sub { my %hash;
      my $reversed_data = reverse($data);
      $hash{reverse($2)} = reverse($1)
          while $reversed_data =~ /\s*([^=]+?)\s*=\s*(\w+)/g;
  },

  "non-reversed" => sub { my %hash; my $data = $data;
      $hash{$1} = $2 while $data =~ s/\s*(\w+)\s*=\s*([^=]+)$//;
  },

});

__DATA__
option1 = value0 value1 value2 option3 =value3 value4 option2=value5
[download]

gives results:

                Rate non-reversed     reversed
non-reversed  1263/s           --         -89%
reversed     10989/s         770%           --
[download]

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Re^3: Parsing named parameters by BrowserUk (Patriarch) on Nov 07, 2005 at 15:18 UTC
But don't do the optimisation unless you need it! What would be the penalty of performing the optimisation if you don't need it? Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal? "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice.	[reply] [d/l]
Re^4: Parsing named parameters by robin (Chaplain) on Nov 07, 2005 at 15:28 UTC
What would be the penalty of performing the optimisation if you don't need it? Why make something more complicated when it doesn't bring you any benefit? Some obvious disadvantages: You waste time writing more complicated code, with no benefit for your application; You make life harder for whoever has to maintain the code later (whether that’s you or someone else), again with no benefit; The optimised code, being more complicated, is more likely to have bugs; etc.	[reply]
Re^5: Parsing named parameters by BrowserUk (Patriarch) on Nov 07, 2005 at 15:30 UTC
I was enquiring after the specific case of your example code, rather than the general case. How many of those still apply? Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal? "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice.	[reply] [d/l]
Re^6: Parsing named parameters by robin (Chaplain) on Nov 07, 2005 at 15:45 UTC
Re^7: Parsing named parameters by BrowserUk (Patriarch) on Nov 07, 2005 at 16:44 UTC

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