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Fix bug statuses of 2000/dlowe

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The doesn't work with some platforms is wrong. It's the perl version and
the author noted this.

There is however a bug that was noted in the bugs file that was not in
the README.md file. This has been moved in the bugs.md file and
README.md file to above the INABIAF part.
This commit is contained in:
Cody Boone Ferguson committed 2024-03-20 06:21:04 -07:00
1 parent cbc022d864
commit c8c88eaa96
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bugs.md
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@@ -1645,69 +1645,10 @@ There was no IOCCC in 1999.
## <a name="2000_dlowe"></a>2000/dlowe
### STATUS: doesn't work with some platforms - please help us fix
### Source code: [2000/dlowe/dlowe.c](2000/dlowe/dlowe.c)
### Information: [2000/dlowe/index.html](2000/dlowe/index.html)
This **MIGHT** be better described as doesn't work with some versions of perl:
the author states that in perl < 5.6.0 there is a bug with a core dump in what
they said is in `Perl_sv_upgrade`. This does not exist in the code, seemingly,
but it might be that this is impossible to fix without getting a perl upgrade.
In any event the below details a problem. Another bug that happens in linux also
is below.
In macOS this program crashes. A tip from Cody is that the code that crashes is:
```c
perl_eval_sv
(newSVpv("_:$_= <> ; defined or exit; @ARGV"
"=split; __:$_= shift;defined or goto _; chomp "
";(m*^\\x70oO" "\\x74$*i)?(pri" "nt \"$_ w\\x"
"61s h\\145r\\x" "65!\\n\"):((m*" "^\\s\\*(-?\\d+"
"(\\.\\d+)?)\\s" "\\*$*)?(push@SS ,$1):(&{chr(((o"
"rd)%39)+3**4)x2 } )); goto __; sub ff { @SS= ("
")} sub __{print \"stack empty\\" "n\"} sub ss{$#"
"SS<0 and goto & __; print $SS[$" "#SS].\"\\n\"} "
"sub SS{ $#SS<0 and goto &__ ; print pop @SS}"
"sub _ { print \"divide by zer" "o\\n\"}sub ii{"
"map{ print\"$_" "\\n\" } reverse @SS} sub AUTOLO"
"AD { print\"un" "implemented\\n" "\"} sub gg{ $#"
"SS<0 and goto &__;push@SS,$SS[ $#SS]} sub uu{ "
"$#SS<1 and goto &__;$SS[ $#SS]+= $SS[$#SS-1];$SS"
"[$#SS-1]=$SS[$" "#SS]-$SS[$#SS-" "1]; $SS[$#SS]-"
"=$SS[$#SS-1]} ",0),0 );
```
and in particular it appears that it is the perl itself. In other words if one
changes it to be:
```c
perl_eval_sv(newSVpv("",0),0);
```
it will not crash. But of course it won't do anything either. So it's more
specifically that the call to `newSVpv()` crashes the code but _INSIDE_
(key point!) the call to `perl_eval_sv()` that does it. Given what the author
stated and that the version of perl is < than 5.6.0 that might be exactly what
is going on.
The example command above _should_ print:
```sh
$ echo "13 14 15 16 17 + - * / p" | ./dlowe
-0.0515873015873016
```
and that's what it shows in linux.
Note that with different perl libraries in macOS (for instance from
[Homebrew](https://brew.sh) and [MacPorts](https://www.macports.org) it will
likely print different warnings when compiling. It was observed that with
Homebrew it does not report any warnings but with MacPorts it results in a total
of 92 warnings! Nonetheless neither works okay and both crash.
### STATUS: known bug - please help us fix
### Source code: [2000/dlowe/dlowe.c](2000/dlowe/dlowe.c)
### Information: [2000/dlowe/index.html](2000/dlowe/index.html)
The author gives an example command:
@@ -1912,6 +1853,63 @@ which might (?) suggest that the `+` operator is unimplemented. Unfortunately it
has been many years since I have used perl and I was never a guru either.
### STATUS: INABIAF - please **DO NOT** fix
The author states that in perl < 5.6.0 there is a bug with a core dump in what
they said is in `Perl_sv_upgrade`. As this is documented it is not considered a
bug to be fixed. For the curious this will crash in macOS. Cody notes that the
code that crashes is:
```c
perl_eval_sv
(newSVpv("_:$_= <> ; defined or exit; @ARGV"
"=split; __:$_= shift;defined or goto _; chomp "
";(m*^\\x70oO" "\\x74$*i)?(pri" "nt \"$_ w\\x"
"61s h\\145r\\x" "65!\\n\"):((m*" "^\\s\\*(-?\\d+"
"(\\.\\d+)?)\\s" "\\*$*)?(push@SS ,$1):(&{chr(((o"
"rd)%39)+3**4)x2 } )); goto __; sub ff { @SS= ("
")} sub __{print \"stack empty\\" "n\"} sub ss{$#"
"SS<0 and goto & __; print $SS[$" "#SS].\"\\n\"} "
"sub SS{ $#SS<0 and goto &__ ; print pop @SS}"
"sub _ { print \"divide by zer" "o\\n\"}sub ii{"
"map{ print\"$_" "\\n\" } reverse @SS} sub AUTOLO"
"AD { print\"un" "implemented\\n" "\"} sub gg{ $#"
"SS<0 and goto &__;push@SS,$SS[ $#SS]} sub uu{ "
"$#SS<1 and goto &__;$SS[ $#SS]+= $SS[$#SS-1];$SS"
"[$#SS-1]=$SS[$" "#SS]-$SS[$#SS-" "1]; $SS[$#SS]-"
"=$SS[$#SS-1]} ",0),0 );
```
and in particular it appears that it is the perl itself. In other words if one
changes it to be:
```c
perl_eval_sv(newSVpv("",0),0);
```
it will not crash. But of course it won't do anything either. So it's more
specifically that the call to `newSVpv()` crashes the code but _INSIDE_
(key point!) the call to `perl_eval_sv()` that does it. Given what the author
stated and that the version of perl is < than 5.6.0 which the author states can
crash this makes sense.
The example command above _should_ print:
```sh
$ echo "13 14 15 16 17 + - * / p" | ./dlowe
-0.0515873015873016
```
and that's what it shows in linux.
Note that with different perl libraries in macOS (for instance from
[Homebrew](https://brew.sh) and [MacPorts](https://www.macports.org) it will
likely print different warnings when compiling. It was observed that with
Homebrew it does not report any warnings but with MacPorts it results in a total
of 92 warnings! Nonetheless neither works okay and both crash.
## <a name="2000_primenum"></a>2000/primenum
### STATUS: INABIAF - please **DO NOT** fix