Ocaml-（int * int * int）列表的字符串

Question

Is in ocaml function which can parse string like this "[(1,2,3);(1,2,5);(2,3,4)]" into (int*int*int) list ? or do I have to write my own parsing function ?

Thanks

Greg

Answer 1

Well, it should not be too difficult with help of the Scanf module from the standard library -- you will be able to scan the triples easily and then only have to add a bit of logic to parse a list.

Alternatively you can take a look at deriving :

Extension to OCaml for deriving functions from type declarations. Includes derivers for pretty-printing, type-safe marshalling with structure-sharing, dynamic typing, equality, and more.

Answer 2

If you're willing to use a somewhat different format, you can have your parser for free. Using the sexplib syntax extension, you can simply write:

type t = (int * int * int) list with sexp

and this will automatically define for you two functions, sexp_of_t and t_of_sexp . Sexplib also provides multiple parsing functions.

The concrete syntax of s-expressions, however, is different. Your example would be rendered:

((1 2 3) (1 2 5) (2 3 4))