What is the difference between the following forms of context introduction?

    Context("LimitedNumeric");
    Context()->texStrings;

The first sets the context to a copy of the LimitedNumeric context. Even if you have used LimtedNumeric context earlier in the problem, you get a fresh copy (any changes you may have made to it earlier are lost. The call returns a reference to the copy, so you could use that to reference the context. So for example

    $context = Context("LimitedNumeric");
    $context->flags->set(reduceConstants=>0);

    Context("LimitedNumeric")->flags->set(reduceConstants=>0);

The second form uses Context() with no name. This returns a reference to the context that is currently in use. So

    Context("LimitedNumeric");
    Context()->flags->set(reduceConstants=>0);

Your command

    Context()->texStrings;

    Context("LimitedNumeric")->texStrings;

Hope that clarifies it.

Davide

    if $self-{value_string} =~ m^\./;

(Note that you also have an error earlier, as it should be $self->{value_string} not $self-{value_string}. The greater-than sign is missing.)

Davide

To create a context, you usually make a copy of an existing one and change it. To store the context where Context() can find it by name, save the copy as $context{name}. For example,

    $context{LeadingZero} = Parser::Context->getCopy("LimitedNumeric");

    Context("LeadingZero");

So your contextLeadingZero.pl file might contain

    loadMacros("contextLimitedNumeric.pl");

     $context{LeadingZero} = Parser::Context->getCopy("LimitedNumeric");
     $context{LeadingZero}->flags->set(
        NumberCheck => sub {
          my $self = shift;
          $self->Error("Decimals must have a number before the decimal point")
            if $self->{value_string} =~ m/^\./;
        }
      );

    loadMacros("contextLeadingZero.pl");

    Context("LeadingZero");
    ....

Note, however, that this is not as general a solution as you might like, as it forces the context to be the LimitedNumeric one. It might be that you want to force leading zeros for some other context. It might be better to make your macro file be one that allows you to modify any context (by setting the NumberCheck flag).

Here's one (unchecked) possibility:

    sub context::LeadingZero {
      my $context = shift || Parser::Context::current;  # context is argument or current context.
      $context->flags->set(NumberCheck => \&context::LeadingZero::NumberCheck;
    }

    sub context::LeadingZero::NumberCheck {
      my $self = shift;
      $self->Error("Decimals must have a number before the decimal point")
        if $self->{value_string} =~ m/^\./;
    }

    loadMacros(
      "contextLimitedNumeric.pl",
      "contextLeadingZero.pl",
    );

    Context("LimitedNumeric");
    context::LeadingZeros;
    .
    .
    .
    ANS(Real(0.23)->cmp);

Hope that helps.

Davide