package Fey::Role::HasAliasName;
BEGIN {
$Fey::Role::HasAliasName::VERSION = '0.40';
}
use strict;
use warnings;
use namespace::autoclean;
use Fey::Types qw( Bool Str );
use MooseX::Role::Parameterized;
parameter 'generated_alias_prefix' => (
isa => Str,
required => 1,
);
parameter 'sql_needs_parens' => (
isa => Bool,
default => 0,
);
has 'alias_name' => (
is => 'rw',
isa => Str,
writer => 'set_alias_name',
);
requires 'sql';
sub alias {
$_[0]->set_alias_name( $_[1] );
return $_[0];
}
sub sql_with_alias {
$_[0]->_make_alias()
unless $_[0]->alias_name();
my $sql = $_[0]->_sql_for_alias( $_[1] );
$sql .= ' AS ';
$sql .= $_[1]->quote_identifier( $_[0]->alias_name() );
return $sql;
}
sub sql_or_alias {
return $_[1]->quote_identifier( $_[0]->alias_name() )
if $_[0]->alias_name();
return $_[0]->sql( $_[1] );
}
role {
my $p = shift;
my $parens = $p->sql_needs_parens();
method _sql_for_alias => sub {
my $sql = $_[0]->sql( $_[1] );
$sql = "( $sql )" if $parens;
return $sql;
};
my $prefix = $p->generated_alias_prefix();
my $num = 0;
method '_make_alias' => sub {
my $self = shift;
$self->set_alias_name( $prefix . $num++ );
};
};
1;
# ABSTRACT: A role for objects that bring an alias with them
=pod
=head1 NAME
Fey::Role::HasAliasName - A role for objects that bring an alias with them
=head1 VERSION
version 0.40
=head1 SYNOPSIS
package My::Thing;
use Moose;
with 'Fey::Role::HasAliasName'
=> { generated_alias_prefix => 'THING' };
=head1 DESCRIPTION
This role adds an C<alias_name> attribute to objects, as well as some
methods for making use of that alias.
=head1 PARAMETERS
=head2 generated_alias_prefix
The prefix that generated aliases will have, e.g. C<LITERAL>,
C<FUNCTION>, etc. Required.
=head2 sql_needs_parens
If true, C<sql_with_alias()> will wrap the output of C<sql()> when
generating its own output. Default is false.
=head1 METHODS
=head2 $obj->alias_name()
Returns the current alias name, if any.
=head2 $obj->set_alias_name()
$obj->set_alias_name('my object');
Sets the current alias name.
=head2 $obj->alias()
$obj->alias('my object')->do_something_else(...);
Sets the current alias name, then returns the object.
=head2 $obj->sql_with_alias()
=head2 $obj->sql_or_alias()
Returns the appropriate SQL snippet. C<sql_with_alias> will generate
an alias if one has not been set (using C<generated_alias_prefix>,
above).
=head1 BUGS
See L<Fey> for details on how to report bugs.
=head1 AUTHOR
Dave Rolsky <autarch@urth.org>
=head1 COPYRIGHT AND LICENSE
This software is Copyright (c) 2011 by Dave Rolsky.
This is free software, licensed under:
The Artistic License 2.0 (GPL Compatible)
=cut
__END__