=head1 NAME

Tk::TM::Try - Tk Transaction Manager Error processing functions.
See Tk::TM::Lib for main descriptions and principles.

=cut
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=pod

=head1 SYNOPSIS

 use Tk::TM::Try;
 Try sub{
      TryHdr('title','stage');
      TryHdr(undef,'stage1');
     }
    ,sub{
     };
 Try(sub{...},0);
 TryDBI $dbh
       ,sub{ #transaction
        }
       ,sub{ #after rollback
        };

=cut
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=pod

=head1 DESCRIPTION

=over

This module implements error processing functions may be used (or not be used)
in application.


=back


=cut
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=pod

=head1 VARIABLES

=over

 use vars qw($ErrorDie $Error);

=item $Tk::TM::Try::ErrorDie

Die if error occurred. Default is false outside C<Try> and true inside.

=item $Tk::TM::Try::Error

Last error occurred. Value is $@.


=back


=cut
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=pod

=head1 FUNCTIONS

=over

 @EXPORT = qw(Try(@) TryDBI(@) TryHdr);


=item Try ( eval {...}, default ) -> result

=item Try ( eval {...}, \&catch ) -> result

=item Try ( sub  {...}, ... ) -> result

Try-Catch construction.
Function C<Try> returns result of eval on success.
If error occurred (determined by $@), it returns default value or result of catch evaluation.


=item TryDBI ( ?dbh, sub {...}, default ) -> result

=item TryDBI ( ?dbh, sub {...}, \&catch ) -> result

Try-Catch construction for database transaction.
Default database handle may be given from current data object or $Tk::TM::Common::DBH.
$dbh->{AutoCommit} and $dbh->{RaiseError} are used inside C<TryDBI>.


=item TryHdr (subject, stage)

=item TryHdr (undef, stage)

Declare title and/or stage name of transaction to insert into $@ inside C<Try>.
May be used only inside C<Try>(sub{},...).


=back


=cut
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=pod

=head1 VERSION

=over


=item "02/04/2000"

Created.

TO DO:

- Approve

- Debug and Test



=back


=cut
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=pod

=head1 AUTHOR

=over

Andrew V Makarow <makarow@mail.com>, Denis E Medvedyuk <demed@mail.com>

=back

=cut