jeltz on \d less efficient than [0-9]

Comment on \d less efficient than [0-9]parent

Happens in Perl but not ruby or PostgreSQL.

Doesn't happen in Perl for me:

  pfedor@Pawels-iMac:~$ perl -ne 'print "Digit!\n" if /\d/'
  af
  3
  Digit!
  23fa3
  Digit!
  asdf
  ١٢٣٤٥٦٧٨٩۰۱۲۳۴۵۶۷۸۹
  ৩৪৫৬৭৮৯੦੧੨੩੪੫੬੭੮੯૦૧૨૩૪૫
  ୧୨୩୪୫୬୭୮
  ౨౩౪౫౬౭౮౯೦೧೨೩೪೫೬೭೮೯൦൧൨൩൪൫൬൭൮൯๐๑๒๓๔๕๖๗๘๙໐໑໒໓
  234
  Digit!

(perl from Macports and perl from /usr/bin/perl behave the same in this respect.)

xonea 13y

You have to tell to interpret stdin as UTF-8 (flag -C) - then it works: https://news.ycombinator.com/item?id=5734641

pfedor 13y

Good to know, thanks.

I'd argue that perl gets it right--as the default behavior, this behavior would gravely violate the principle of least surprise, but for the 0.01% of people who want \d to match ੧, there's no harm to making it available as an option you need to specifically request.

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