This just came up on the PDL mailing list. Any thoughts on how the build might have failed like this? Do we check for PDL in general but not the PLplot module in particular? 

We have a sort of circular dependency here where it can be confusing to the PDL user whether to install PLplot or PDL first if they want to use both.

-Hazen

Begin forwarded message:

From: P Kishor <punk.kish@gmail.com>
Date: August 29, 2009 12:03:52 AM EDT
To: perldl <perldl@jach.hawaii.edu>
Subject: Re: [Perldl] surfaces with PDL
Reply-To: punkish@eidesis.org

sorry to be replying here to my own rantings... I went ahead and
followed the instructions listed below to install plplot, but received
the following error

-- PDL_VERSION = 2.4.4
-- PDL version >= 2.4.1.  Enabling Perl/PDL examples in tests
-- PDL_PLPLOT_VERSION = Can't locate PDL/Graphics/PLplot.pm in @INC
(@INC contains: /usr/local/lib/perl5/5.8.8/darwin-2level
/usr/local/lib/perl5/5.8.8
/usr/local/lib/perl5/site_perl/5.8.8/darwin-2level
/usr/local/lib/perl5/site_perl/5.8.8 /usr/local/lib/perl5/site_perl
.).
BEGIN failed--compilation aborted.

CMake Error at cmake/modules/plplot.cmake:71 (math):
  math cannot parse the expression: "0*1000000 + Can't locate
  PDL/Graphics/PLplot.pm in @INC (@INC contains:
  /usr/local/lib/perl5/5.8.8/darwin-2level /usr/local/lib/perl5/5.8.8
  /usr/local/lib/perl5/site_perl/5.8.8/darwin-2level
  /usr/local/lib/perl5/site_perl/5.8.8 /usr/local/lib/perl5/site_perl .).

  BEGIN failed--compilation aborted.

  .0*1000 + Can't locate PDL/Graphics/PLplot.pm in @INC (@INC contains:
  /usr/local/lib/perl5/5.8.8/darwin-2level /usr/local/lib/perl5/5.8.8
  /usr/local/lib/perl5/site_perl/5.8.8/darwin-2level
  /usr/local/lib/perl5/site_perl/5.8.8 /usr/local/lib/perl5/site_perl .).

  BEGIN failed--compilation aborted.

  .0": syntax error, unexpected exp_DIVIDE, expecting exp_OPENPARENT or
  exp_NUMBER (29)
Call Stack (most recent call first):
  cmake/modules/pdl.cmake:71 (transform_version)
  cmake/modules/plplot.cmake:428 (include)
  CMakeLists.txt:82 (include)



I thought plplot was the prerequisite for PDL::Graphics::PLplot, but
it seems to be the other way around. Now I am really confused and
stuck.

Suggestions welcome.