search

Perl / perl5

🐪 The Perl programming language
https://dev.perl.org/perl5/
Other
1.85k stars 523 forks source link

Pod does not get ignored by perl #43

Closed p5pRT closed 20 years ago

p5pRT commented 24 years ago

Migrated from rt.perl.org#845 (status was 'resolved')

Searchable as RT845$

p5pRT commented 24 years ago

From pfeiffer@start.de

This is a bug report for perl from occitan@​esperanto.org\, generated with the help of perlbug 1.26 running under perl 5.00502.

While you go about this\, a little remark. When using =cut a lot it sticks out like a sore thumb\, distracting from the code. It would be neat if (given that this is a sort of closing paren) qr/\bcut=$/ would perform the same trick. I'm thinking about writing a Pod.pm parser\, which the various incarnations would inherit from and only worry about the generating-half of the job.

In the style of literate programming I just mingled the pod into a very long statement (GetOptions which is several pages long\, and I documented every option on the spot\, for one thing to be sure to cover them all\, for another to make the weird option specs clearer).

The = signs before item and cut are not seen\, probably erroneously parsed as assignments\, even though they are on paragraphs of their own. A real pity the perlpod's assertion "Perl will ignore the pod text." doesn't hold. Silly example​:

=head1 test

=over

=cut

print

=item number

=cut

  1\,

=item newline

=cut

  "\n";

=back

gives​:

Number found where operator expected at test.pl line 13\, near "cut

  1"   (Do you need to predeclare cut?) syntax error at test.pl line 13\, near "cut

  1" String found where operator expected at test.pl line 19\, near "cut

  "\n""   (Do you need to predeclare cut?) Execution of test.pl aborted due to compilation errors.

Site configuration information for perl 5.00502​:

Configured by root at Sun Apr 4 19​:59​:20 /etc/localtime 1999.

Summary of my perl5 (5.0 patchlevel 5 subversion 2) configuration​:   Platform​:   osname=linux\, osvers=2.2.5\, archname=i586-linux   uname='linux pascal 2.2.5 #79 tue jan 19 12​:41​:20 met 1999 i686 unknown '   hint=recommended\, useposix=true\, d_sigaction=define   usethreads=undef useperlio=undef d_sfio=undef   Compiler​:   cc='cc'\, optimize='-O2 -pipe'\, gccversion=egcs-2.91.66 19990314 (egcs-1.1.2 release)   cppflags='-Dbool=char -DHAS_BOOL -I/usr/local/include'   ccflags ='-Dbool=char -DHAS_BOOL -I/usr/local/include'   stdchar='char'\, d_stdstdio=define\, usevfork=false   intsize=4\, longsize=4\, ptrsize=4\, doublesize=8   d_longlong=define\, longlongsize=8\, d_longdbl=define\, longdblsize=12   alignbytes=4\, usemymalloc=n\, prototype=define   Linker and Libraries​:   ld='cc'\, ldflags =' -L/usr/local/lib'   libpth=/usr/local/lib /lib /usr/lib   libs=-lnsl -lndbm -lgdbm -ldb -ldl -lm -lc -lposix -lcrypt   libc=\, so=so\, useshrplib=false\, libperl=libperl.a   Dynamic Linking​:   dlsrc=dl_dlopen.xs\, dlext=so\, d_dlsymun=undef\, ccdlflags='-rdynamic'   cccdlflags='-fpic'\, lddlflags='-shared -L/usr/local/lib'

Locally applied patches​:  

@​INC for perl 5.00502​:   /usr/lib/perl5/5.00502/i586-linux   /usr/lib/perl5/5.00502   /usr/lib/perl5/site_perl/5.005/i586-linux   /usr/lib/perl5/site_perl/5.005   .

Environment for perl 5.00502​:   HOME=/home/pfeiffer   LANG (unset)   LD_LIBRARY_PATH (unset)   LOGDIR (unset)   PATH=/home/pfeiffer/bin​:/usr/local/system/scripts​:/usr/local/bin​:/bin​:/usr/bin​::/sbin​:/usr/sbin​:/usr/games/bin​:/usr/bin/X11​:/opt/kde/bin   PERL_BADLANG (unset)   SHELL=/bin/ksh

Site configuration information for perl 5.00502​:

Configured by root at Sun Apr 4 19​:59​:20 /etc/localtime 1999.

Summary of my perl5 (5.0 patchlevel 5 subversion 2) configuration​:   Platform​:   osname=linux\, osvers=2.2.5\, archname=i586-linux   uname='linux pascal 2.2.5 #79 tue jan 19 12​:41​:20 met 1999 i686 unknown '   hint=recommended\, useposix=true\, d_sigaction=define   usethreads=undef useperlio=undef d_sfio=undef   Compiler​:   cc='cc'\, optimize='-O2 -pipe'\, gccversion=egcs-2.91.66 19990314 (egcs-1.1.2 release)   cppflags='-Dbool=char -DHAS_BOOL -I/usr/local/include'   ccflags ='-Dbool=char -DHAS_BOOL -I/usr/local/include'   stdchar='char'\, d_stdstdio=define\, usevfork=false   intsize=4\, longsize=4\, ptrsize=4\, doublesize=8   d_longlong=define\, longlongsize=8\, d_longdbl=define\, longdblsize=12   alignbytes=4\, usemymalloc=n\, prototype=define   Linker and Libraries​:   ld='cc'\, ldflags =' -L/usr/local/lib'   libpth=/usr/local/lib /lib /usr/lib   libs=-lnsl -lndbm -lgdbm -ldb -ldl -lm -lc -lposix -lcrypt   libc=\, so=so\, useshrplib=false\, libperl=libperl.a   Dynamic Linking​:   dlsrc=dl_dlopen.xs\, dlext=so\, d_dlsymun=undef\, ccdlflags='-rdynamic'   cccdlflags='-fpic'\, lddlflags='-shared -L/usr/local/lib'

Locally applied patches​:  

@​INC for perl 5.00502​:   /usr/lib/perl5/5.00502/i586-linux   /usr/lib/perl5/5.00502   /usr/lib/perl5/site_perl/5.005/i586-linux   /usr/lib/perl5/site_perl/5.005   .

Environment for perl 5.00502​:   HOME=/home/pfeiffer   LANG (unset)   LC_CTYPE=de_DE   LD_LIBRARY_PATH (unset)   LOGDIR (unset)   PATH=/home/pfeiffer/bin​:/usr/local/system/scripts​:/usr/local/bin​:/bin​:/usr/bin​::/sbin​:/usr/sbin​:/usr/games/bin​:/usr/bin/X11​:/opt/kde/bin   PERL_BADLANG (unset)   SHELL=/bin/bash

p5pRT commented 24 years ago

From [Unknown Contact. See original ticket]

This bug is still present in 5.6. Porters\, anyone game to track it down?

Nat

This is a bug report for perl from occitan@​esperanto.org\, generated with the help of perlbug 1.26 running under perl 5.00502. ----------------------------------------------------------------- While you go about this\, a little remark. When using =cut a lot it sticks out like a sore thumb\, distracting from the code. It would be neat if (given that this is a sort of closing paren) qr/\bcut=$/ would perform the same trick. I'm thinking about writing a Pod.pm parser\, which the various incarnations would inherit from and only worry about the generating-half of the job.

In the style of literate programming I just mingled the pod into a very long statement (GetOptions which is several pages long\, and I documented every option on the spot\, for one thing to be sure to cover them all\, for another to make the weird option specs clearer).

The = signs before item and cut are not seen\, probably erroneously parsed as assignments\, even though they are on paragraphs of their own. A real pity the perlpod's assertion "Perl will ignore the pod text." doesn't hold. Silly example​:

=head1 test

=over

=cut

print

=item number

=cut

1\,

=item newline

=cut

"\\n";

=back

gives​:

Number found where operator expected at test.pl line 13\, near "cut

1"
\(Do you need to predeclare cut?\)

syntax error at test.pl line 13\, near "cut

1"

String found where operator expected at test.pl line 19\, near "cut

"\\n""
\(Do you need to predeclare cut?\)

Execution of test.pl aborted due to compilation errors.

p5pRT commented 24 years ago

From [Unknown Contact. See original ticket]

The funny thing is that if it's the first pod directive in the file\, the first =cut doesn't.

--tom

p5pRT commented 24 years ago

From [Unknown Contact. See original ticket]

This bug is still present in 5.6. Porters\, anyone game to track it down?

The = signs before item and cut are not seen\, probably erroneously parsed as assignments\, even though they are on paragraphs of their own. A real pity the perlpod's assertion "Perl will ignore the pod text." doesn't hold. Silly example​:

This is because POD directives (or whatever the are called\, the paragraphs beginning with an =) must occur where Perl expects a new statement. At least\, this is what I have found to be true through testing.

But I don't know what to do about it\, since "I'm more of an idea rat."

-- MIDN 4/C PINYAN\, NROTCURPI\, US Naval Reserve japhy@​pobox.com http​://www.pobox.com/~japhy/ http​://pinyaj.stu.rpi.edu/ PerlMonth - An Online Perl Magazine http​://www.perlmonth.com/ The Perl Archive - Articles\, Forums\, etc. http​://www.perlarchive.com/

p5pRT commented 24 years ago

From [Unknown Contact. See original ticket]

This is because POD directives (or whatever the are called\, the paragraphs beginning with an =) must occur where Perl expects a new statement. At least\, this is what I have found to be true through testing.

perlsyn​:

  Perl has a mechanism for intermixing documentation with   source code. While it's expecting the beginning of a new   statement\, if the compiler encounters a line that begins   with an equal sign and a word\, like this

That could be more clearly worded\, but the intent is there.

--tom

p5pRT commented 24 years ago

From [Unknown Contact. See original ticket]

Tom Christiansen writes​:

This is because POD directives (or whatever the are called\, the paragraphs beginning with an =) must occur where Perl expects a new statement. At least\, this is what I have found to be true through testing.

perlsyn​: That could be more clearly worded\, but the intent is there.

Good enough for me. I'll mark it closed.

Nat

p5pRT commented 24 years ago

From [Unknown Contact. See original ticket]

On Mon\, 20 Mar 2000\, Tom Christiansen wrote​:

This is because POD directives (or whatever the are called\, the paragraphs beginning with an =) must occur where Perl expects a new statement. At least\, this is what I have found to be true through testing.

perlsyn​:

   Perl has a mechanism for intermixing documentation with
   source code\.  While it's expecting the beginning of a new
   statement\, if the compiler encounters a line that begins
   with an equal sign and a word\, like this

There's also an allusion in perlfaq7 under "How can I comment out a large block of perl code?"​:

  This can't go just anywhere. You have to put a pod   directive where the parser is expecting a new statement\,   not just in the middle of an expression or some other   arbitrary yacc grammar production.

Cheers\, Philip -- Philip Newton \newton@​newton\.digitalspace\.net

p5pRT commented 24 years ago

From [Unknown Contact. See original ticket]

Hmm. Why doesn't Perl like reading a lot from STDIN?

perl -Mdiagnostics -e 'read(FOO\,$FOO\,2 ** 31 - 1)'

runs smoothly.

perl -Mdiagnostics -e 'read(STDIN\,$STDIN\,2 ** 31 - 1)'

Out of memory during "large" request for -2147479552 bytes at -e line 1 (#1)

(F) The malloc() function returned 0\, indicating there was insufficient remaining memory (or virtual memory) to satisfy the request. However\, the request was judged large enough (compile-time default is 64K)\, so a possibility to shut down by trapping this error is granted.

Perhaps if you actually read from something you could read from you might get a different answer.

  % perl -Mdiagnostics -e '*FOO = *STDIN; read(FOO\,$FOO\,2 ** 31 - 1)'   panic​: realloc at -e line 1 (#1)  
  (P) Something requested a negative number of bytes of realloc.  
  Uncaught exception from user code​:   panic​: realloc at -e line 1.

Word to the wise​: always read in only as much as is there\, and always check you got what you asked for. And don't be trying to go preallocating these (off_t (-1)) sized buffers. That's a crackhead move.

In some cases\, this is ok not to\, in others\, it isn't. If you know how much is there\, certainly check. If you don't know how much is there\, use a block at a time--very carefully. You need to understand about partial reads and writes.

  use Errno qw/EINTR/;   $blksize = (stat FROM)[11] || 16384; # preferred block size?   while ($len = sysread FROM\, $buf\, $blksize) {   if (!defined $len) {   next if $! == EINTR;   die "System read error​: $!\n";   }   $offset = 0;   while ($len) { # Handle partial writes.   $written = syswrite TO\, $buf\, $len\, $offset;   die "System write error​: $!\n" unless defined $written;   $offset += $written;   $len -= $written;   }   }

--tom