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[Caml-list] Pattern matching and strings
- Alessandro Baretta
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| Date: | -- (:) |
| From: | Alessandro Baretta <alex@b...> |
| Subject: | [Caml-list] Pattern matching and strings |
I have to do a little bit of pattern matching on strings. My
first instict was to write something like the following.
let foo x = ...
let bar x = ...
... = function
| "foo" ^ rest -> foo rest
| "bar" ^ rest -> bar rest
| _ -> raise Unrecognized
Of course, this is not possible because (^) is an operator
rather than a constructor. Since I believe that the above
code is much more natural and idiomatic than code based on
regexps, I wonder how much compiler magic it would take to
make it work. Probably all it takes is some syntax-magic
since the above can be mapped onto the following:
open Scanf
... = function x -> begin
try sscanf x "foo%[^]" foo with Scan_failure _ ->
try sscanf x "bar%[^]" bar with Scan_failure _ ->
raise Unrecognized
end
An equivalent mapping could be done with the Str library or
any other regexp library.
However, the former is much cleaner. If it could be had, I'd
appreciate it.
Alex
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