The time is probably spent parsing the grammar,

Hmm. Seems not. I just put separate timings around the ->new and the ->parse and the former took just 1 second.

The other day I wanted to compare the time taken and resilience of our solutions. It doesn't matter a jot for the OPs application as there are a maximum of 26 drives, but I was interested in the comparative performance of my solution.

Rather than doing a full benchmark, I thought I'd just create a file with enough data that the timings came out in seconds. I tried mine against 676 records ('aa'..'zz'), but it was well under a second so I generated 17,576 records (<c>'aaa'..'zzz'/<c>) and it took around 5 seconds.

I then started your Parse::RecDescent solution against the same file and went off and did something else. When I returned, it had already consumed well over an hour of cpu and eventually finished having consumed 98 minutes of cpu on a quiescent system! So in 1 1/2 hours or so time I should get how long the parsing takes.

I know P::RD isn't the quickest thing on the block, but this difference is way greater than the last time I measured. There has to be something about this particular grammar that is causing it to go so slowly, but I'm not sufficiently familiar with P::RD to recognise what?

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.

In reply to Re^5: Pulling data out of { } by BrowserUk
in thread Pulling data out of { } by Felix2000

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