Annotation of /sml/trunk/src/ml-yacc/examples/calc/calc.lex

Parent Directory | Revision Log

---

Revision 2 - (view) (download)

1 :	monnier	2	structure Tokens = Tokens
2 :
3 :			type pos = int
4 :			type svalue = Tokens.svalue
5 :			type ('a,'b) token = ('a,'b) Tokens.token
6 :			type lexresult= (svalue,pos) token
7 :
8 :			val pos = ref 0
9 :			fun eof () = Tokens.EOF(!pos,!pos)
10 :			fun error (e,l : int,_) = TextIO.output (TextIO.stdOut, String.concat[
11 :			"line ", (Int.toString l), ": ", e, "\n"
12 :			])
13 :
14 :			%%
15 :			%header (functor CalcLexFun(structure Tokens: Calc_TOKENS));
16 :			alpha=[A-Za-z];
17 :			digit=[0-9];
18 :			ws = [\ \t];
19 :			%%
20 :			\n => (pos := (!pos) + 1; lex());
21 :			{ws}+ => (lex());
22 :			{digit}+ => (Tokens.NUM (valOf (Int.fromString yytext), !pos, !pos));
23 :
24 :			"+" => (Tokens.PLUS(!pos,!pos));
25 :			"*" => (Tokens.TIMES(!pos,!pos));
26 :			";" => (Tokens.SEMI(!pos,!pos));
27 :			{alpha}+ => (if yytext="print"
28 :			then Tokens.PRINT(!pos,!pos)
29 :			else Tokens.ID(yytext,!pos,!pos)
30 :			);
31 :			"-" => (Tokens.SUB(!pos,!pos));
32 :			"^" => (Tokens.CARAT(!pos,!pos));
33 :			"/" => (Tokens.DIV(!pos,!pos));
34 :			"." => (error ("ignoring bad character "^yytext,!pos,!pos);
35 :			lex());
36 :
37 :

---

root@smlnj-gforge.cs.uchicago.edu	ViewVC Help
Powered by ViewVC 1.0.0