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.\" ========================================================================
.\"
.IX Title "HTML::Widget::Constraint::CallbackOnce 3pm"
.TH HTML::Widget::Constraint::CallbackOnce 3pm "2007-03-01" "perl v5.18.1" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.SH "NAME"
HTML::Widget::Constraint::CallbackOnce \- CallbackOnce Constraint
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 5
\&    my $c = $widget\->constraint( \*(AqCallbackOnce\*(Aq, \*(Aqfoo\*(Aq, \*(Aqbar\*(Aq )\->callback(
\&      sub { 
\&        my ($foo, $bar) = @_;
\&        return 1 if $foo == $bar * 2;
\&    });
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
A callback constraint which will only be run once for each call of 
\&\*(L"process\*(R" in HTML::Widget.
.SH "METHODS"
.IX Header "METHODS"
.SS "callback"
.IX Subsection "callback"
.SS "cb"
.IX Subsection "cb"
Arguments: \e&callback
.PP
Requires a subroutine reference used for validation, which will be passed 
a list of values corresponding to the constraint names.
.PP
\&\*(L"cb\*(R" is provided as an alias to \*(L"callback\*(R".
.SS "process"
.IX Subsection "process"
Overrides \*(L"process\*(R" in HTML::Widget::Constraint to ensure \*(L"validate\*(R" is 
only called once for each call of \*(L"validate\*(R".
.SS "render_errors"
.IX Subsection "render_errors"
Arguments: \f(CW@names\fR
.PP
A list of element names for which an error should be displayed.
.PP
If this is not set, the default behaviour is for the error to be displayed 
for all of the Constraint's named elements.
.SS "validate"
.IX Subsection "validate"
perform the actual validation.
.SH "AUTHOR"
.IX Header "AUTHOR"
Carl Franks \f(CW\*(C`cfranks@cpan.org\*(C'\fR
.SH "LICENSE"
.IX Header "LICENSE"
This library is free software, you can redistribute it and/or modify it under
the same terms as Perl itself.