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