thoc: don't nest calls to follow() when lexing ++/+= and --/-= (#287) - plan9port - [fork] Plan 9 from user space
HTML git clone git://src.adamsgaard.dk/plan9port
DIR Log
DIR Files
DIR Refs
DIR README
DIR LICENSE
---
DIR commit f1dd3f065a97f57bf59db2e3284868e181734159
DIR parent 9389de63d7b0dab99773511f48b2d303e3f957d7
HTML Author: deepcube <evan.gates@gmail.com>
Date: Thu, 19 Sep 2019 10:10:28 -0700
hoc: don't nest calls to follow() when lexing ++/+= and --/-= (#287)
The code had a nested use of the follow() function that could cause +=+
and -=- to register as ++ and --. The first follow() to execute could
consume a character and match and then the second follow() could consume
another character and match. For example i-=-10 would result in a syntax
error and i-=- would decrement i.
Diffstat:
M src/cmd/hoc/hoc.y | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
---
DIR diff --git a/src/cmd/hoc/hoc.y b/src/cmd/hoc/hoc.y
t@@ -215,8 +215,8 @@ yylex(void) /* hoc6 */
return STRING;
}
switch (c) {
- case '+': return follow('+', INC, follow('=', ADDEQ, '+'));
- case '-': return follow('-', DEC, follow('=', SUBEQ, '-'));
+ case '+': return follow('+', INC, '+') == INC ? INC : follow('=', ADDEQ, '+');
+ case '-': return follow('-', DEC, '-') == DEC ? DEC : follow('=', SUBEQ, '-');
case '*': return follow('=', MULEQ, '*');
case '/': return follow('=', DIVEQ, '/');
case '%': return follow('=', MODEQ, '%');