mpri-funcprog-project/src/Lexer.mll

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2017-12-13 14:04:28 +01:00
{
open Lexing
open Error
open Parser
open RawLambda
}
(* -------------------------------------------------------------------------- *)
(* Regular expressions. *)
let newline =
('\010' | '\013' | "\013\010")
let whitespace =
[ ' ' '\t' ]
let lowercase =
['a'-'z' '\223'-'\246' '\248'-'\255' '_']
let uppercase =
['A'-'Z' '\192'-'\214' '\216'-'\222']
let identchar =
['A'-'Z' 'a'-'z' '_' '\192'-'\214' '\216'-'\246' '\248'-'\255' '0'-'9']
let digit =
['0'-'9']
(* -------------------------------------------------------------------------- *)
(* The lexer. *)
rule entry = parse
| "fun"
{ FUN }
| "in"
{ IN }
| "let"
{ LET }
| "print"
{ PRINT }
| "rec"
{ REC }
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| "ifzero"
{ IFZERO }
| "then"
{ THEN }
| "else"
{ ELSE }
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| "->"
{ ARROW }
| "="
{ EQ }
| "("
{ LPAREN }
| ")"
{ RPAREN }
| "+"
{ ADDOP OpAdd }
| "-"
{ ADDOP OpSub }
| "*"
{ MULOP OpMul }
| "/"
{ MULOP OpDiv }
| (lowercase identchar *) as x
{ IDENT x }
| digit+ as i
{ try
INTLITERAL (int_of_string i)
with Failure _ ->
error (place lexbuf) "invalid integer literal." }
| "(*"
{ ocamlcomment (place lexbuf) lexbuf; entry lexbuf }
| newline
{ new_line lexbuf; entry lexbuf }
| whitespace+
{ entry lexbuf }
| eof
{ EOF }
| _ as c
{ error (place lexbuf) "unexpected character: '%c'." c }
(* ------------------------------------------------------------------------ *)
(* Skip OCaml-style comments. Comments can be nested. This sub-lexer is
parameterized with the place of the opening comment, so if an unterminated
comment is detected, we can show where it was opened. *)
and ocamlcomment p = parse
| "*)"
{ () }
| "(*"
{ ocamlcomment (place lexbuf) lexbuf; ocamlcomment p lexbuf }
| newline
{ new_line lexbuf; ocamlcomment p lexbuf }
| eof
{ error p "unterminated comment." }
| _
{ ocamlcomment p lexbuf }