(define sample
"(?P<x>
"[^x]+(?P<nx>
)
I still remember looking through the ejabberd source code, trying to find their xml parser. When it finally dawned on me that it was automagically hidden in the pattern matching, I was impressed.
Monday, February 13, 2012
pattern matching with regexps
This is just a reminder to myself to think about extending pattern matching to regular expressions on strings. It'd be a great feature, though with the famous caveat about regular expressions. [I have a problem. I think I can solve it with regular expressions. Now I have two problems.]
(define sample
"(?P<x>[0-9]+)+(?P<y>[0-9]+)" -> (+ (string->int x) (string->int y))
"[^x]+(?P<nx>x+)[^x]+" -> (string-length nx)
)
I still remember looking through the ejabberd source code, trying to find their xml parser. When it finally dawned on me that it was automagically hidden in the pattern matching, I was impressed.
(define sample
"(?P<x>
"[^x]+(?P<nx>
)
I still remember looking through the ejabberd source code, trying to find their xml parser. When it finally dawned on me that it was automagically hidden in the pattern matching, I was impressed.
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Generalizing a bit, how about another syntax for pattern matching on 'regular languages':
ReplyDelete(regmatch x with
(reg:concat (reg:+ (reg:class (class:whitespace)))
[xs (reg:* (reg:class (class:char #\x)))]
(reg:+ (reg:class (class:whitespace)))
)
-> xs)
Where [var exp] binds that sub-expression to a variable...
[sadly I can't seem to wrap that with pre so it's probably unreadable]
Also, need to see what facilites erlang might have that are similar.