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PATCH (!): Re: PATCH: (very) bad syntax error checking
- X-seq: zsh-workers 11606
- From: "Bart Schaefer" <schaefer@xxxxxxxxxxxxxxxxxxxxxxx>
- To: Peter Stephenson <pws@xxxxxxxxxxxxxxxxxxxxxxxxx>, zsh-workers@xxxxxxxxxxxxxx (Zsh hackers list)
- Subject: PATCH (!): Re: PATCH: (very) bad syntax error checking
- Date: Sat, 27 May 2000 08:13:47 +0000
- In-reply-to: <0FV6007MP80O0S@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
- Mailing-list: contact zsh-workers-help@xxxxxxxxxxxxxx; run by ezmlm
- References: <0FV6007MP80O0S@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
On May 26, 3:24pm, Peter Stephenson wrote:
} Subject: PATCH: (very) bad syntax error checking
}
} It's rather late in the day to come across problems like this.
}
} % zsh -f ./test.zsh
} ./test.zsh:3: parse error near `fi'
} This line should not be executed.
This was supposedly fixed, by PWS, in zsh-workers/4191, before the 3.1.5
release; though Zefram changed it slightly, according to the ChangeLog.
As it happens, one of the customizations I have in my local copy of 3.1.6
is the patch from zsh-workers/4196, which I've been stubbornly hanging on
to ever since Zefram chose not to include it in 3.1.5, so I tried it with
ARGV0=ksh:
zagzig[274] Src/zsh -f /tmp/foo/test.zsh
/tmp/foo/test.zsh:3: parse error near `fi'
This line should not be executed.
zagzig[275] ARGV0=ksh Src/zsh -f /tmp/foo/test.zsh
/tmp/foo/test.zsh:3: parse error near `fi'
zagzig[276]
That would seem to mean the problem is with the value of `noerrexit' around
line 123 of init.c, but in fact that's NOT the case. Here again is the
shell code in question:
if true; # then missing
print hello
fi
Remove the first two lines; then:
zagzig[277] Src/zsh -f /tmp/foo/test.zsh
/tmp/foo/test.zsh:1: parse error near `fi'
This line should not be executed.
zagzig[278] ARGV0=ksh Src/zsh -f /tmp/foo/test.zsh
/tmp/foo/test.zsh:1: parse error near `fi'
This line should not be executed.
So the problem is twofold; first, there appears to be some very old cruft
in par_if() in parse.c left over from when the SHORT_LOOPS option affected
the bodies of "if" statements. This causes the ksh/zsh difference I first
noticed. Unfortunately, I don't know how to remove it without breaking
still-valid csh-compat syntax like `if (true) print hello'. It probably
doesn't need to be removed after fixing the next problem.
Second, encountering the token "fi" alone on a line is not setting the
returned token to LEXERR, so in init.c the test of (tok == LEXERR) fails
(the value of `tok' is, not surpisingly, `FI').
What follows appears to fix it, but Sven should confirm. For one thing,
I wonder why parse_list() doesn't use YYERROR() ... is there some reason
why `ecused' should not be set to 0 in that specific case?
I included a hunk for the grammar test, but why is the line number `-1'?
(The init.c hunk is just some whitespace cleanup.)
Index: Src/parse.c
===================================================================
@@ -459,6 +459,7 @@
}
}
if (!r) {
+ tok = LEXERR;
if (errflag) {
yyerror(0);
ecused--;
@@ -491,10 +492,8 @@
yylex();
init_parse();
par_list(&c);
-#if 0
- if (tok == LEXERR)
-#endif
- if (tok != ENDINPUT) {
+ if (tok != ENDINPUT) {
+ tok = LEXERR;
yyerror(0);
return NULL;
}
Index: Src/init.c
===================================================================
@@ -944,7 +944,7 @@
execode(prog, 1, 0);
popheap();
} else
- loop(0, 0); /* loop through the file to be sourced */
+ loop(0, 0); /* loop through the file to be sourced */
sourcelevel--;
/* restore the current shell state */
Index: Test/01grammar.ztst
===================================================================
@@ -105,6 +105,11 @@
fi
0:`if ...' (iii)
>false
+ if true;
+ :
+ fi
+1d:`if ...' (iv)
+?ZTST_execchunk:-1: parse error near `fi'
for name in word to term; do
print $name
--
Bart Schaefer Brass Lantern Enterprises
http://www.well.com/user/barts http://www.brasslantern.com
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