Parsing "Key" = "Value" pair - objective-c

Question

I'm trying to parse the string in the folowing format using the regex:
"Key" = "Value";
The following code is used to extract the "key" and "value":
NSString* pattern = #"([\"\"'])(?:(?=(\\\\?))\\2.)*?\\1";
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:pattern
options:0
error:NULL];
NSRange matchRange = NSMakeRange(0, line.length);
NSTextCheckingResult *match = [regex firstMatchInString:line options:0 range:matchRange];
NSRange rangeKeyMatch = [match rangeAtIndex:0];
matchRange.location = rangeKeyMatch.length;
matchRange.length = line.length - rangeKeyMatch.length;
NSTextCheckingResult *match2 = [regex firstMatchInString:line options:0 range:matchRange];
NSRange rangeValueMatch = [match2 rangeAtIndex:0];
It doesn't look efficient and is not considering the following example as invalid:
"key" = "value" = "something else";
Is there any efficient way to perform parse of this kind of parsing?

Answer 1

I'm not familiar with that dialect, but since you've tagged regex, here's one that should do it in principle: ^"([^"]*)" = "([^"]*)";$
You're not being exact about the format so you may need to add some conditional white-space here and there depending on your input format. Another thing that might come into play is the need to escape the parentheses.
For example with sed, you'd have to write:
echo '"Key" = "Value";' | sed -e 's#^"\([^"]*\)" = "\([^"]*\)";$#key is \1 and value is \2#'

Answer 2

This code should match "key" = "value" and not "key" = "value" = "something else":
NSString *line = #"\"key\" = \"value\"";
NSError *error = NULL;
NSString *pattern = #"\\\"(\\w+)\\\"\\s=\\s\\\"(\\w+)\\\"$";
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:pattern
options:NSRegularExpressionAnchorsMatchLines error:&error];
NSRange matchRange = NSMakeRange(0, line.length);
NSTextCheckingResult *match = [regex firstMatchInString:line options:0 range:matchRange];
/* It looks like you were not quite looking at the ranges properly. The rangeAtIndex 0 is actually the entire string. */
NSRange rangeKeyMatch = [match rangeAtIndex:1];
NSRange rangeValueMatch = [match rangeAtIndex:2];
NSLog(#"Key: %#, Value: %#", [line substringWithRange:rangeKeyMatch], [line substringWithRange:rangeValueMatch]);