From mike@tecc.co.uk

My suggestion​: I'd like to be able to turn on a warning that lets me
know if my program contains function calls to functions that I haven't
defined. So for example​:

  my $a1 = foo1();
  if ($a1 == 3) {
  $a1 = foo2();
  }
  print "a1 is $a1\n";

  sub foo1 {
  return 2;
  }

should report "foo2() not defined" when given the appropriate
options. (This is a lot like the sort of reporting you get from the
linker when you use Boring Old-Fashioned Languages.)

I appreciate that there is an overhead here, so you'd not want this to
be the default behaviour. But I think it's trivial to implement
(right? Just walk the parse-tree before starting the run). It would
help to ensure that programs that work today don't stop working
tomorrow when someone feeds them input that wanders off down a
different code-path.

Thanks for listening,

  Mike Taylor
  TECC Ltd.
  mike@​tecc.co.uk
  Tel. +44 181 880 4040

(Oh, and thanks for Perl -- loving it!)

From [Unknown Contact. See original ticket]

At 03​:21 PM 11/19/99 +0000, Mike Taylor wrote​:

Apologies for sending this to what I suspect is an inappropriate
address, but would you mind forwarding it for me please?
(And what's the <suggestion-box@​perl.org> address?)

My suggestion​: I'd like to be able to turn on a warning that lets me
know if my program contains function calls to functions that I haven't
defined.

Except this will kill​:

1) AUTOLOADed things
2) A goodly chunk of the perl core modules that have platform-specific
function calls in code protected by "if ($^O eq 'whatever')"
3) Code that requires things
4) Code written by folks getting altogether too clever with symbol tables

Nothing insurmountable, though fixing #2 would take some work. (Presumably
people affected by 1, 3, or 4 just Won't Do That)

  Dan

----------------------------------------"it's like this"-------------------
Dan Sugalski even samurai
dan@​sidhe.org have teddy bears and even
  teddy bears get drunk

From [Unknown Contact. See original ticket]

Date​: Fri, 19 Nov 1999 10​:35​:30 -0500
From​: Dan Sugalski <dan@​sidhe.org>

My suggestion​: I'd like to be able to turn on a warning that lets me
know if my program contains function calls to functions that I haven't
defined.

Except this will kill​:

1) AUTOLOADed things

Uuuh ...

2) A goodly chunk of the perl core modules that have platform-specific
function calls in code protected by "if ($^O eq 'whatever')"

Erm ...

3) Code that requires things

Duh!

4) Code written by folks getting altogether too clever with symbol tables

Ahem.

But otherwise, it's great idea, right? :-)

Nothing insurmountable, though fixing #2 would take some
work. (Presumably people affected by 1, 3, or 4 just Won't Do That)

Hmm, I can't see it. Never mind, and thanks for the ultra-prompt
reply! (BTW., was perlbug a reasonable address to send this to?)

  Mike Taylor
  TECC Ltd.
  mike@​tecc.co.uk
  Tel. +44 181 880 4040

From [Unknown Contact. See original ticket]

But otherwise, it's great idea, right? :-)

Yes, actually.

Hmm, I can't see it. Never mind, and thanks for the ultra-prompt
reply! (BTW., was perlbug a reasonable address to send this to?)

No, you have a good point. It's exceedingly annoying to
have a program die halfway through due to a seldom traversed
codepath that includes a call to the lenght() function. Some
pragma could be arranged to help this.

  no autoload;
or
  use warnings 'undefuncalls';

or some such.

That doesn't solve the issue for method calls, and it is compile-time only
warnings. I'm not sure whether this should be foisted off into
B​::Lint as it is now. Did you know about that? This​:

  perl -MO=Lint,-context,-undefined-subs myperlprogram

might make you happy. Then again, that's hardly a user-friendly
front end. What ever happened to the idea of a plint program
that did the icky work for you, akin to perlcc?

--tom

From [Unknown Contact. See original ticket]

At 03​:56 PM 11/19/99 +0000, Mike Taylor wrote​:

But otherwise, it's great idea, right? :-)

Yep. Heck, I'd love to have it at times too. None of the problems are
insurmountable, just a touch tricky.

  Dan

----------------------------------------"it's like this"-------------------
Dan Sugalski even samurai
dan@​sidhe.org have teddy bears and even
  teddy bears get drunk

From [Unknown Contact. See original ticket]

Date​: Fri, 19 Nov 1999 09​:01​:41 -0700
From​: Tom Christiansen <tchrist@​jhereg.perl.com>

But otherwise, it's great idea, right? :-)

Yes, actually.

Oh, thanks :-)

I'm not sure whether this should be foisted off into B​::Lint as it
is now. Did you know about that? This​:

perl \-MO=Lint\,\-context\,\-undefined\-subs myperlprogram

might make you happy.

Ah, no I didn't know about that -- many thanks, I'll check it out.
But does it make me happy? Not necessarily, since the scripts where I
most want to be able to do this sort of static checking are CGI
scripts running on IIS/NT <hurl noice="bletch"> which I fear I will
have trouble persuading to do what I want. Then again, as this is a
purely compile-time issue, I guess I can still run the lint phase on
Unix ... Hmm, I'll try it out.

Then again, that's hardly a user-friendly front end. What ever
happened to the idea of a plint program that did the icky work for
you, akin to perlcc?

No idea, I've only been writing Perl since July!

  Mike Taylor
  TECC Ltd.
  mike@​tecc.co.uk
  Tel. +44 181 880 4040

From [Unknown Contact. See original ticket]

Dan Sugalski writes​:

At 03​:56 PM 11/19/99 +0000, Mike Taylor wrote​:

But otherwise, it's great idea, right? :-)

Yep. Heck, I'd love to have it at times too. None of the problems are
insurmountable, just a touch tricky.

Since it would be lexical, it will not be even as bad as that. You
try it once, then you switch it off. ;-)

Ilya