Which regular expression engine?

11 years ago in General • updated by 8 years ago • 3

Thanks for a great app! I have some questions regarding regular expressions, though:

- Which regular expression engine does Textastic use?
- Where can I find the syntax spec?
- What is the right syntax for including captures in the replacement text?
- Can I use case modifiers like \U \L \u in the replacement text?

TIA for the answer which I hope end up in the FAQ/manual! (Is there a FAQ distinct from the manual?

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11 years ago

Search and Replace in Textastic for iPhone and iPad uses the NSRegularExpression class which in turn uses the syntax that is specified by ICU.

See http://developer.apple.com/library/mac/#documentation/Foundation/Reference/NSRegularExpression_Class/Reference/Reference.html#//apple_ref/doc/uid/TP40009708-CH1-SW53

and

http://userguide.icu-project.org/strings/regexp

Textastic supports the same replacement string syntax as TextMate. See http://manual.macromates.com/en/regular_expressions#replacement_string_syntax_format_strings

You can reference captures using $1, $2 etc.

Case foldings and conditional insertions are supported as described in the TextMate manual.

11 years ago

OK thanks! A rather Perlish syntax which is good from my POV. Outside the phone I'm on Linux or occasionally Windows + Vim so my experience with Textmate is nil. Nice syntax for conditional branching in the replacement!
/bpj

8 years ago

Three years later (time flies) the `(?:CAPTURENUMBER:IF-MATCH:ELSE) syntax doesn't work anymore (on iOS)? I haven't used it in a while

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