[hackers] [9base] hoc: Don't nest calls to follow() when lexing ++/+= and --/-= || Evan Gates

[git]

commit 63916da7bd6d73d9a405ce83fc4ca34845667cce
Author:     Evan Gates <e...@gnarbox.com>
AuthorDate: Wed Sep 11 15:46:27 2019 -0700
Commit:     Anselm R Garbe <ans...@garbe.ca>
CommitDate: Fri Sep 13 15:56:15 2019 +0000

    hoc: Don't nest calls to follow() when lexing ++/+= and --/-=
    
    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.

diff --git a/hoc/hoc.y b/hoc/hoc.y
index 9c5a02f..f634e82 100644
--- a/hoc/hoc.y
+++ b/hoc/hoc.y
@@ -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, '%');