Extract known pattern substring from NSString (without regex)
- by d11wtq
I'm really tempted to drop RegexKit (or my own libpcre wrapper) into my project in order to do this, but before I do that I want to know how Cocoa developers manage to do half of this basic stuff without really convoluted code or without linking with RegexKit or another regular expression library.
I find it gobsmacking that Cocoa does not include any regular expression matching features. I've so accustomed to using regular expressions for all kinds of things that I'm lost without them. I can do what I need without them, but the code would be rather convoluted. So, Cocoa devs, I ask you, what's the "Cocoa way" to do this...
The problem is an everyday problem in programming as far as I'm concerned. Cocoa must have ways of doing this with the built-in features. Note that the position of the elements I want to match changes, and sometimes "quotes" are present. Whitespace is variable.
Take the following strings:
Content-Type: application/xml; charset=utf-8
Content-Type: text/html; charset="iso-8859-1"
Content-Type: text/plain;
charset=us-ascii
Content-Type: text/plain; name="example.txt"; charset=utf-8
From all of these strings, how would you go about determining the mime type (e.g. text/plain) and the charset (e.g. utf-8) using just the built-in Cocoa classes?
I'd end up performing a series of -rangeOfString: and substring calls, with conditional checks to deal with the optional quotes etc. Is there a way to do this with NSScanner? The NSScanner class seems to have a pretty naive API to me.
Something like C's sscanf() that works for NSString objects would be an ideal fit. Most of my string parsing needs are simple such as this example so maybe regular expressions, while I'm accustomed to them, are overkill?
