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lexer.mll
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lexer.mll
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{
exception Syntax_error of string
let reserved_words = [
("if", Parser.IF);
("else", Parser.ELSE);
("for", Parser.FOR);
("while", Parser.WHILE);
("or", Parser.OR);
("and", Parser.AND);
("func", Parser.FUNC);
("local", Parser.LOCAL);
("true", Parser.TRUE);
("false", Parser.FALSE);
("return", Parser.RETURN);
]
}
let int = '0' | (['1'-'9']['0'-'9']*)
let identifier = ['a'-'z' 'A'-'Z'] ['a'-'z' 'A'-'Z' '0'-'9' '_']*
rule read = parse
| [' ' '\009' '\012' '\n']+ { read lexbuf }
| "==" { Parser.EQ }
| "!=" { Parser.NE }
| "<=" { Parser.LE }
| ">=" { Parser.GE }
| '<' { Parser.LT }
| '>' { Parser.GT }
| '=' { Parser.ASSIGN }
| '(' { Parser.LPAREN }
| ')' { Parser.RPAREN }
| '{' { Parser.LBRACE }
| '}' { Parser.RBRACE }
| '+' { Parser.PLUS }
| '-' { Parser.MINUS }
| '*' { Parser.MULT }
| '/' { Parser.DIV }
| ';' { Parser.SEMI }
| ',' { Parser.COMMA }
| eof { Parser.EOF }
| int { Parser.NUMBER (int_of_string (Lexing.lexeme lexbuf)) }
| identifier
{ let id = Lexing.lexeme lexbuf in
try
List.assoc id reserved_words
with
_ -> Parser.IDENTIFIER (id)
}
| _ { raise (Syntax_error ("Unexpected char: " ^ (Lexing.lexeme lexbuf))) }