PDF::FromHTML::Template::Container::Conditional - PDF::FromHTML::Template::Container::Conditional documentation


PDF-FromHTML documentation Contained in the PDF-FromHTML distribution.

Index


Code Index:

NAME

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PDF::FromHTML::Template::Container::Conditional

PURPOSE

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To conditionally allow children to render

NODE NAME

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CONDITIONAL IF (an alias for CONDITIONAL)

INHERITANCE

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PDF::FromHTML::Template::Container

ATTRIBUTES

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* NAME - Required. This is a parameter name, whose value will determine if the conditional passed or fails. If NAME is not specified, the conditional will consider to always fail.
* OP - defaults to == (numeric equality). If VALUE is specified, this will be how NAME and VALUE are compared. OP can be any of the 6 numeric comparision operators or the 6 string comparision operators.
* VALUE - if this is specified, OP will be checked. This is a standard attribute, so if you want a parameter, prepend it with '$'.
* IS - If there is no VALUE attribute, this will be checked. IS can be either 'FALSE' or 'TRUE'. The boolean of NAME will be compared and the conditional will branch appropriately. If NAME has no value, this will fail.
* NONE - If there is no IS and no VALUE, then an attempt will be made to find the variable defined by NAME. If it exists and is true, the condition will succeed. Otherwise, it will fail.

CHILDREN

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None

AFFECTS

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Nothing

DEPENDENCIES

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None

USAGE

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  <if name="__PAGE__" OP="!=" VALUE="__LAST_PAGE__">
    ... Children execute if the current page is not the last page ...
  </if>

  <if name="Param1" OP="eq" VALUE="$Param2">
    ... Children execute if Param1 is string-wise equals to Param2 ...
  </if>

AUTHOR

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Rob Kinyon (rkinyon@columbus.rr.com)

SEE ALSO

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PDF-FromHTML documentation Contained in the PDF-FromHTML distribution.

package PDF::FromHTML::Template::Container::Conditional;

#GGG Convert <conditional> to be a special case of <switch>?

use strict;

BEGIN {
    use vars qw(@ISA);
    @ISA = qw(PDF::FromHTML::Template::Container);

    use PDF::FromHTML::Template::Container;
}

my %isOp = (
    '='  => '==',
    (map { $_ => $_ } ( '>', '<', '==', '!=', '>=', '<=' )),
    (map { $_ => $_ } ( 'gt', 'lt', 'eq', 'ne', 'ge', 'le' )),
);

# This cannot be within a should_render() function because the conditional needs
# to return true even if the conditional is false. We are indicating that this
# branch has done everything it needs to do, not that this branch is calling for
# a pagebreak.

sub conditional_passes
{
    my $self = shift;
    my ($context) = @_;

    my $name = $context->get($self, 'NAME');
    return 0 unless $name =~ /\S/;

    my $val = $context->param($name);
    $val = @{$val} while UNIVERSAL::isa($val, 'ARRAY');
    $val = ${$val} while UNIVERSAL::isa($val, 'SCALAR');

    my $istrue = (defined $val && $val) ? 1 : 0;
    my $value = $context->get($self, 'VALUE');
    if (defined $value)
    {
        my $op = $context->get($self, 'OP');
        $op = defined $op && exists $isOp{$op}
            ? $isOp{$op}
            : '==';

        my $res;
        for ($op)
        {
            /^>$/  && do { $res = ($val > $value);  last };
            /^<$/  && do { $res = ($val < $value);  last };
            /^==$/ && do { $res = ($val == $value); last };
            /^!=$/ && do { $res = ($val != $value); last };
            /^>=$/ && do { $res = ($val >= $value); last };
            /^<=$/ && do { $res = ($val <= $value); last };
            /^gt$/ && do { $res = ($val gt $value); last };
            /^lt$/ && do { $res = ($val lt $value); last };
            /^eq$/ && do { $res = ($val eq $value); last };
            /^ne$/ && do { $res = ($val ne $value); last };
            /^ge$/ && do { $res = ($val ge $value); last };
            /^le$/ && do { $res = ($val le $value); last };

            die "Unknown operator '$op' in conditional resolve", $/;
        }

        return 1;
    }
    elsif (my $is = uc $context->get($self, 'IS'))
    {
        if ($is eq 'TRUE')
        {
            return $istrue;
        }
        else
        {
            warn "Conditional 'is' value was [$is], defaulting to 'FALSE'" . $/
                if $is ne 'FALSE';

            return !$istrue;
        }
    }

    return $istrue;
}

sub render
{
    my $self = shift;
    my ($context) = @_;

    return 0 unless $self->should_render($context);

    return 1 unless $self->conditional_passes($context);

    return $self->iterate_over_children($context);
}

sub max_of
{
    my $self = shift;
    my ($context, $attr) = @_;

    return 0 unless $self->conditional_passes($context);

    return $self->SUPER::max_of($context, $attr);
}

sub total_of
{
    my $self = shift;
    my ($context, $attr) = @_;

    return 0 unless $self->conditional_passes($context);

    return $self->SUPER::total_of($context, $attr);
}

sub _do_page
{
    my $self = shift;
    return unless $self->conditional_passes(@_);
    return $self->SUPER::_do_page( @_ );
}

sub begin_page
{
    _do_page(@_,'begin_page');
}

sub end_page
{
    _do_page(@_,'end_page');
}

1;
__END__