perl 1.0 patch #15
The Superuser
lroot at devvax.JPL.NASA.GOV
Thu Feb 4 11:12:24 AEST 1988
System: perl version 1.0
Patch #: 15
Priority: HIGHER than a kite
Subject: 1+1 is parsed wrong! eval always returns null string!
From: markb at rdcf.sm.unisys.com (Mark Biggar)
From: lwall at jpl-devvax.jpl.nasa.gov (Larry Wall)
Description:
The tokener screws up on parsing number literals and can gobble
a following + or - that doesn't belong to it. 1+1 is interpreted
as 1e+1. 1+1+1 has the value 2. 1+$foo is a syntax error!
Leave it to my brother-in-law to find a bug as horrible as this.
The eval operator was always returning a null string, contray to
the documentation. This turned out to be because the do_eval()
routine was freeing the structure holding the return value before
it could be copied elsewhere.
Included are more tests to detect the above behavior.
There's also a fix to a piddly little bug that won't show up unless
you are trying to blow perl up on purpose. If you say "1 x -1;"
perl will loop forever. But that only happens if both operands of "x"
are evaluated at compile time! The runtime routines handle negative
counts reasonably. (No, they don't give you a string of negative
length. Sorry. That would have been interesting to see, I know.)
As a bonus for those of you who have read this far, I've included
a little perl script called perlsh. It's a poor man's perl shell.
Just type perl stuff at it, and whenever you want it to evaluate what
you've typed (which must be syntactically complete) just type
two carriage returns in a row. Useful for trying out odd little
things in perl without writing a script. The whole script has just
4 lines of code.
Fix: From rn, say "| patch -p0 -d DIR", where DIR is your perl source
^^^
directory. Outside of rn, say "cd DIR; patch -p0 <thisarticle".
If you don't have the patch program, apply the following by hand,
or get patch (version 2.0 patchlevel 9).
If patch indicates that patchlevel is the wrong version, you may need
to apply one or more previous patches, or the patch may already
have been applied. See the patchlevel.h file to find out what has or
has not been applied. In any event, don't continue with the patch.
If you are missing previous patches they can be obtained from me:
Larry Wall
lwall at jpl-devvax.jpl.nasa.gov
If you send a mail message of the following form it will greatly speed
processing:
Subject: Command
@SH mailpatch PATH perl 1.0 LIST
^ note the c
where PATH is a return path FROM ME TO YOU in Internet notation, and
LIST is the number of one or more patches you need, separated by spaces,
commas, and/or hyphens. Saying 35- says everything from 35 to the end.
You can also get the patches via anonymous FTP from
jpl-devvax.jpl.nasa.gov (128.149.8.43).
Index: patchlevel.h
Prereq: 14
1c1
< #define PATCHLEVEL 14
---
> #define PATCHLEVEL 15
Index: t/base.lex
Prereq: 1.0.1.1
*** t/base.lex.old Wed Feb 3 16:28:51 1988
--- t/base.lex Wed Feb 3 16:28:52 1988
***************
*** 1,8 ****
#!./perl
! # $Header: base.lex,v 1.0.1.1 88/01/28 10:37:00 root Exp $
! print "1..6\n";
$ # this is the register <space>
= 'x';
--- 1,8 ----
#!./perl
! # $Header: base.lex,v 1.0.1.2 88/02/03 16:27:16 root Exp $
! print "1..7\n";
$ # this is the register <space>
= 'x';
***************
*** 30,32 ****
--- 30,36 ----
eval '$foo{1} / 1;';
if (!$@) {print "ok 6\n";} else {print "not ok 6\n";}
+
+ eval '$foo = 123+123.4+123e4+123.4E5+123.4e+5+.12;';
+
+ if ($foo eq 25910246.52) {print "ok 7\n";} else {print "not ok 7\n";}
Index: t/op.eval
*** t/op.eval.old Wed Feb 3 16:45:37 1988
--- t/op.eval Wed Feb 3 16:45:38 1988
***************
*** 1,6 ****
#!./perl
! print "1..6\n";
eval 'print "ok 1\n";';
--- 1,6 ----
#!./perl
! print "1..7\n";
eval 'print "ok 1\n";';
***************
*** 12,20 ****
eval "\$foo\n = # this is a comment\n'ok 4\n';";
print $foo;
! eval '
$foo ='; # this tests for a call through yyerror()
if ($@ =~ /line 2/) {print "ok 5\n";} else {print "not ok 5\n";}
! eval '$foo = /'; # this tests for a call through fatal()
if ($@ =~ /Search/) {print "ok 6\n";} else {print "not ok 6\n";}
--- 12,22 ----
eval "\$foo\n = # this is a comment\n'ok 4\n';";
print $foo;
! print eval '
$foo ='; # this tests for a call through yyerror()
if ($@ =~ /line 2/) {print "ok 5\n";} else {print "not ok 5\n";}
! print eval '$foo = /'; # this tests for a call through fatal()
if ($@ =~ /Search/) {print "ok 6\n";} else {print "not ok 6\n";}
+
+ print eval '"ok 7\n";';
Index: perlsh
*** perlsh.old Wed Feb 3 16:28:21 1988
--- perlsh Wed Feb 3 16:28:25 1988
***************
*** 0 ****
--- 1,12 ----
+ #!/bin/perl
+
+ # Poor man's perl shell.
+
+ # Simply type two carriage returns every time you want to evaluate.
+ # Note that it must be a complete perl statement--don't type double
+ # carriage return in the middle of a loop.
+
+ $/ = ''; # set paragraph mode
+ while (<>) {
+ eval; print $@ || "\n";
+ }
Index: perly.c
Prereq: 1.0.1.3
*** perly.c.old Wed Feb 3 16:28:35 1988
--- perly.c Wed Feb 3 16:28:39 1988
***************
*** 1,6 ****
! char rcsid[] = "$Header: perly.c,v 1.0.1.3 88/01/28 10:28:31 root Exp $";
/*
* $Log: perly.c,v $
* Revision 1.0.1.3 88/01/28 10:28:31 root
* patch8: added eval operator. Also fixed expectterm following right curly.
*
--- 1,10 ----
! char rcsid[] = "$Header: perly.c,v 1.0.1.4 88/02/03 16:25:19 root Exp $";
/*
* $Log: perly.c,v $
+ * Revision 1.0.1.4 88/02/03 16:25:19 root
+ * patch15: 1+$foo confused tokener.
+ * Also, the return value in do_eval got tromped by cmd_free().
+ *
* Revision 1.0.1.3 88/01/28 10:28:31 root
* patch8: added eval operator. Also fixed expectterm following right curly.
*
***************
*** 1581,1598 ****
decimal:
arg[1].arg_type = A_SINGLE;
d = tokenbuf;
! while (isdigit(*s) || *s == '_')
*d++ = *s++;
! if (*s == '.' && index("0123456789eE",s[1]))
*d++ = *s++;
! while (isdigit(*s) || *s == '_')
! *d++ = *s++;
! if (index("eE",*s) && index("+-0123456789",s[1]))
! *d++ = *s++;
! if (*s == '+' || *s == '-')
! *d++ = *s++;
! while (isdigit(*s))
! *d++ = *s++;
*d = '\0';
arg[1].arg_ptr.arg_str = str_make(tokenbuf);
break;
--- 1585,1612 ----
decimal:
arg[1].arg_type = A_SINGLE;
d = tokenbuf;
! while (isdigit(*s) || *s == '_') {
! if (*s == '_')
! s++;
! else
! *d++ = *s++;
! }
! if (*s == '.' && index("0123456789eE",s[1])) {
*d++ = *s++;
! while (isdigit(*s) || *s == '_') {
! if (*s == '_')
! s++;
! else
! *d++ = *s++;
! }
! }
! if (index("eE",*s) && index("+-0123456789",s[1])) {
*d++ = *s++;
! if (*s == '+' || *s == '-')
! *d++ = *s++;
! while (isdigit(*s))
! *d++ = *s++;
! }
*d = '\0';
arg[1].arg_ptr.arg_str = str_make(tokenbuf);
break;
***************
*** 1890,1896 ****
break;
case O_REPEAT:
i = (int)str_gnum(s2);
! while (i--)
str_scat(str,s1);
break;
case O_MULTIPLY:
--- 1904,1910 ----
break;
case O_REPEAT:
i = (int)str_gnum(s2);
! while (i-- > 0)
str_scat(str,s1);
break;
case O_MULTIPLY:
***************
*** 2513,2519 ****
if (retval)
str = &str_no;
else {
! str = cmd_exec(eval_root);
cmd_free(myroot); /* can't free on error, for some reason */
}
in_eval--;
--- 2527,2534 ----
if (retval)
str = &str_no;
else {
! str = str_static(cmd_exec(eval_root));
! /* if we don't save str, free zaps it */
cmd_free(myroot); /* can't free on error, for some reason */
}
in_eval--;
More information about the Comp.sources.bugs
mailing list