Affected: urweb.lex
1. Oversized int literals throw an unhandled Overflow exception in SML
Basis Int64.fromString, making the lexer fail.
Documentation: http://sml-family.org/Basis/integer.html#SIG:INTEGER.scan:VAL
Adding
handle Overflow => NONE
solves it.
2. Hexadecimal literals are defined too shortly, and refuse values
bigger then 32 bits.
hexconst = 0x[0-9A-F]{1,8};
The actual definition with max. repetitions specifier, causes an
oversized literal to be split in two tokens making the error ugly.
It is better to accept the whole token and check for the Overflow when
converted, adding the exception handler as with the previous section.
(This bug is from a proposal of mine, so It was my fault)
--- ../../urweb-20150520/src/urweb.lex 2015-04-12 20:22:03.000000000 +0200
+++ urweb-20150520/src/urweb.lex 2015-05-26 13:08:07.509897000 +0200
@@ -182,7 +182,7 @@
ws = [\ \t\012\r];
intconst = [0-9]+;
realconst = [0-9]+\.[0-9]*;
-hexconst = 0x[0-9A-F]{1,8};
+hexconst = 0x[0-9A-F]+;
notags = ([^<{\n(]|(\([^\*<{\n]))+;
xcom = ([^\-]|(-[^\-]))+;
oint = [0-9][0-9][0-9];
@@ -542,17 +542,25 @@
<INITIAL> {id} => (Tokens.SYMBOL (yytext, pos yypos, pos yypos + size yytext));
<INITIAL> {cid} => (Tokens.CSYMBOL (yytext, pos yypos, pos yypos + size yytext));
-<INITIAL> {hexconst} => (case StringCvt.scanString (Int64.scan StringCvt.HEX) (String.extract (yytext, 2, NONE)) of
+<INITIAL> {hexconst} => (let val digits = String.extract (yytext, 2, NONE) ;
+ val v = (StringCvt.scanString (Int64.scan StringCvt.HEX) digits)
+ handle Overflow => NONE
+ in
+ case v of
SOME x => Tokens.INT (x, pos yypos, pos yypos + size yytext)
| NONE => (ErrorMsg.errorAt' (pos yypos, pos yypos)
("Expected hexInt, received: " ^ yytext);
- continue ()));
+ continue ())
+ end);
-<INITIAL> {intconst} => (case Int64.fromString yytext of
+<INITIAL> {intconst} => (let val v = (Int64.fromString yytext) handle Overflow => NONE
+ in
+ case v of
SOME x => Tokens.INT (x, pos yypos, pos yypos + size yytext)
| NONE => (ErrorMsg.errorAt' (pos yypos, pos yypos)
("Expected int, received: " ^ yytext);
- continue ()));
+ continue ())
+ end);
<INITIAL> {realconst} => (case Real64.fromString yytext of
SOME x => Tokens.FLOAT (x, pos yypos, pos yypos + size yytext)
| NONE => (ErrorMsg.errorAt' (pos yypos, pos yypos)
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