Whoops, I meant Are you numbers constrained to be from 1 to 9? How about 0677 (which is actually 6 and 77) or 0607 (which is actually 607) etc?
Phil On Aug 10, 2013, at 2:54 PM, Tom Davie <tom.da...@gmail.com> wrote: > > On 10 Aug 2013, at 22:44, Keary Suska <cocoa-...@esoteritech.com> wrote: > >> On Aug 10, 2013, at 12:17 PM, Tom Davie wrote: >> >>> Heh, I’d actually argue that NSScanner is a much much better API to use >>> here (and in fact nearly everywhere). Regular expressions constrain you >>> only to regular grammars, which are a pretty small set. In my experience >>> 99% of the use of them is actually trying to parse something that’s not >>> *quite* a regular grammar, and uses a hack on top of regular expressions to >>> do something not-quite-right. >>> >>> NSScanner by comparison makes the separation of what’s >>> scanning/tokenisation, and what’s up to your (turing complete) program much >>> more clear. So basically, (at least in my opinion), if you want to parse >>> something that’s regular, NSScanner is a great choice. If you want to >>> parse something that’s context free, look at CoreParse (Not tooting my own >>> horn, honest). And finally, if you want to parse something that’s more >>> even than that, then you’re probably back to NSScanner and a turing >>> complete program. >>> >>> About the only use for regular expressions I can think of is asking >>> NSScanner to scan something that it doesn’t by default know about. >> >> I would agree that NSScanner is a better API than NSRegularExpression, but I >> think that is Apple's fault because there are better regex API's, such as >> RegexKit. >> >> I would argue, however, that it is NSScanner that only functions well with >> fixed and unvarying grammars and has no context, other than a specific, >> unvarying linear progression. Regular expressions have a huge grammar and >> when you consider conditionals and zero-width assertions you can parse >> information that would send NSScanner into dizzying fits. >> >> Not to mention that NSScanner can't even touch the problem that the OP is >> experiencing, while regular expressions will handle it very nicely. > > No, some hacked on extensions to regular expressions can do this. Because > people keep repeatedly bumping into the problem that they’re not as powerful > as CFGs, and most parsing problems aren’t regular. > > Tom Davie > _______________________________________________ > > Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) > > Please do not post admin requests or moderator comments to the list. > Contact the moderators at cocoa-dev-admins(at)lists.apple.com > > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/cocoa-dev/ershler%40cvrti.utah.edu > > This email sent to ersh...@cvrti.utah.edu Philip R. Ershler Ph.D. University of Utah Cardiovascular Research and Training Institute 95 South 2000 East Salt Lake City, UT 84112-5000 phone: (801) 230-8771 alt ph: (801) 587-9528 fax: (801) 581-3128 e-mail: ersh...@cvrti.utah.edu _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/ershler%40cvrti.utah.edu This email sent to ersh...@cvrti.utah.edu _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
