NAME¶
Object::Declare - Declarative object constructor
SYNOPSIS¶
use Object::Declare ['MyApp::Column', 'MyApp::Param'];
my %objects = declare {
param foo =>
!is global,
is immutable,
valid_values are qw( more values );
column bar =>
field1 is 'value',
field2 is 'some_other_value',
sub_params are param( is happy ), param ( is sad );
};
print $objects{foo}; # a MyApp::Param object
print $objects{bar}; # a MyApp::Column object
# Assuming that MyApp::Column::new simply blesses into a hash...
print $objects{bar}{sub_params}[0]; # a MyApp::Param object
print $objects{bar}{sub_params}[1]; # a MyApp::Param object
DESCRIPTION¶
This module exports one function, "declare", for building named
objects with a declarative syntax, similar to how Jifty::DBI::Schema defines
its columns.
In list context, "declare" returns a list of name/object pairs in the
order of declaration (allowing duplicates), suitable for putting into a hash.
In scalar context, "declare" returns a hash reference.
Using a flexible "import" interface, one can change exported helper
functions names (
declarator), words to link labels and values together
(
copula), and the table of named classes to declare (
mapping):
use Object::Declare
declarator => ['declare'], # list of declarators
copula => { # list of words, or a map
is => '', # from copula to label prefixes,
are => '', # or to callback that e.g. turns
has => sub { has => @_ }, # "has X" to "has is X" and
# "X has 1" to "has is [X => 1]"
},
aliases => { # list of label aliases:
more => 'less', # turns "is more" into "is less"
# and "more is 1" into "less is 1"
},
mapping => {
column => 'MyApp::Column', # class name to call ->new to
param => sub { # arbitrary coderef also works
bless(\@_, 'MyApp::Param');
},
};
After the declarator block finishes execution, all helper functions are removed
from the package. Same-named functions (such as &is and &are) that
existed before the declarator's execution are restored correctly.
NOTES¶
If you export the declarator to another package via @EXPORT, be sure to export
all mapping keys as well. For example, this will work for the example above:
our @EXPORT = qw( declare column param );
But this will not:
our @EXPORT = qw( declare );
The copula are not turned into functions, so there is no need to export them.
AUTHORS¶
Audrey Tang <cpan@audreyt.org>
COPYRIGHT¶
Copyright 2006, 2007 by Audrey Tang <cpan@audreyt.org>.
This software is released under the MIT license cited below.
The "MIT" License¶
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation the
rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO
EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.