I'm trying to build up some skills in lexing/parsing grammars. I'm looking back on a simple parser I wrote for SQL, and I'm not altogether happy with it -- it seems like there should have been an easier way to write the parser. SQL tripped me up because it has a lot of optional tokens and repitition. For example: SELECT * FROM t1 INNER...
I have a parser and lexer written in ocamlyacc and ocamllex. If the file to parse ends prematurely, as in I forget a semicolon at the end of a line, the application doesn't raise a syntax error. I realize it's because I'm raising and catching EOF and that is making the lexer ignore the unfinished rule, but how should I be doing this to r...
I'm using ocamlyacc and ocamllex. I have an error production in my grammar that signals a custom exception. So far, I can get it to report the error position: | error { raise (Parse_failure (string_of_position (symbol_start_pos ()))) } But, I also want to know which token was read. There must be a way---anyone know? Thanks. ...
I'm OCaml newbie and I'm trying to write a simple OCaml-like grammar, and I can't figure this out. My grammar allows something like this: let sub = fun x -> fun y -> x - y;; However, if I want to use the function so defined, I can write: (sub 7) 3 but I can't write sub 7 3, which really bugs me. For some reason, it gets interpreted as...
Is there any way to return multiple tokens in OCamlLex? I'm trying to write a lexer and parser for an indentation based language, and I would like my lexer to return multiple DEDENT tokens when it notices that the indentation level is less than it previously was. This will allow it to notify the parser when multiple blocks have ended...