Author Devin Jeanpierre
Recipients Devin Jeanpierre, akitada, akoumjian, alex, amaury.forgeotdarc, belopolsky, davide.rizzo, eric.snow, ezio.melotti, georg.brandl, giampaolo.rodola, gregory.p.smith, jacques, jaylogan, jhalcrow, jimjjewett, loewis, mark, mattchaput, moreati, mrabarnett, ncoghlan, nneonneo, pitrou, r.david.murray, ronnix, rsc, sjmachin, steven.daprano, stiv, timehorse, vbr, zdwiel
Date 2012-01-29.08:01:42
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Message-id <1327824104.2.0.639258920542.issue2636@psf.upfronthosting.co.za>
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> In practice, I expect that a pure Python implementation of a regular expression engine would only be fast enough to be usable on PyPy.

Not sure why this is necessarily true. I'd expect a pure-Python implementation to be maybe 200 times as slow. Many queries (those on relatively short strings that backtrack little) finish within microseconds. On this scale, a couple of orders of magnitudes is not noticeable by humans (unless it adds up), and even where it gets noticeable, it's better than having nothing at all or a non-working program (up until a point).

python -m timeit -n 1000000 -s "import re; x = re.compile(r'.*<\s*help\s*>([^<]*)<\s*/\s*help.*>'); data = ' '*1000 + '< help >' + 'abc'*100 + '</help>'" "x.match(data)"
1000000 loops, best of 3: 3.27 usec per loop
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Date User Action Args
2012-01-29 08:01:44Devin Jeanpierresetrecipients: + Devin Jeanpierre, loewis, georg.brandl, gregory.p.smith, jimjjewett, sjmachin, amaury.forgeotdarc, ncoghlan, belopolsky, pitrou, nneonneo, giampaolo.rodola, rsc, timehorse, mark, vbr, ezio.melotti, mrabarnett, jaylogan, akitada, moreati, steven.daprano, alex, r.david.murray, jacques, zdwiel, jhalcrow, stiv, davide.rizzo, mattchaput, ronnix, eric.snow, akoumjian
2012-01-29 08:01:44Devin Jeanpierresetmessageid: <1327824104.2.0.639258920542.issue2636@psf.upfronthosting.co.za>
2012-01-29 08:01:43Devin Jeanpierrelinkissue2636 messages
2012-01-29 08:01:43Devin Jeanpierrecreate