Just curious, but how did you get 9,751 lines into your code before discovering that you couldn't create an object?

Does Materia::Variable::Pressure have a new method? If not does Materia::Variable have a new method? If there is a new method can you reduce the problem to a simple case, for example cutting out all the methods except new?

=pod

Build up our list of hashes from 14th Chart of the Nuclides data.

=cut

my $hydrogen = {};
{
    $hydrogen->{element}{Z} = 1;

    $hydrogen->{name}{default}    = 'Hydrogen';
    $hydrogen->{name}{'en-CA'}    = 'Hydrogen';
    # Names for other countries/languages/charactersets.

    $hydrogen->{symbol}{default} = 'H';
    $hydrogen->{symbol}{'en-CA'} = 'H';
    # Symbols for other countries/languages/charactersets.

    $hydrogen->{element}{mass}    =  Materia::Variable::Generic->new({
    value => '1.00794(7)',
    name => 'MolarMass',
    units => 'g',
                                     });
    $hydrogen->{boilT} = Materia::Variable::Pressure->new({
    value    =>  '20.268',
    name     => 'BoilT',
    units    => 'K',
    pressure => {
        value => '101.325E3',
        units => 'Pa',
    }, 
                              });
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There are 106 elements of data, each one has a stanza about twice as long as this snippet for Hydrogen. The object is to merge a bunch of different data sources (some on paper, some electronically readable) into a database. But that is how this got to be almost 10,000 lines long.

But the first creation of a Generic object, to store the Molar Mass of Hydrogen works. The next object to be created, the Boiling Point of Hydrogen (at a pressure of 1 atmosphere) fails.

As written in the original note, the ::Generic, ::Pressure, ::Temperature and ::PressureTemperature modules have new methods. These methods do very little, mostly they shuffle a little information and call _init() in the base class.

Anytime I find a problem, I redo the make/make install of these modules, so that what this program is loading when I run perldb in emacs is up to date. I don't just rerun the program from the beginning, I kill the perldb session in emacs and start it over again. But I have never run into this before where it looks like I have loaded the module, but at run time it can't find it. It's strange.

Probably a typo in your post, but a typo would cause this sort of problem:
"Materia::Variable::Pressure". I think you want "Material::Variable::Pressure".

Also, have you considered putting expressions into a hash building expression? I find that style much more readable (especially after reading large amounts of Data::Dumper output).

my $hydrogen = { element => { Z => 1,
                  mass => ...,
                },
         name => { default => 'Hydrogen',
               'en-CA' => 'Hydrogen',
             },
         symbol => { ... },
         boilT => ...,
           };
[download]

• The loading statements (as you have provided, thanks)
• The call site that fails (with any relevant surrounding context)
• The package and loading statements of the module in question
• The method in question