SQL::Translator::Producer::TT::Base - TT based Producer base class.


SQL::Translator::Producer::TT::Base - TT (Template Toolkit) based Producer base class.


 # Create a producer using a template in the __DATA__ section.
 package SQL::Translator::Producer::Foo;
 use base qw/SQL::Translator::Producer::TT::Base/;
 # Convert produce call into a method call on our new class
 sub produce { return __PACKAGE__->new( translator => shift )->run; };
 # Configure the Template object.
 sub tt_config { ( INTERPOLATE => 1 ); }
 # Extra vars to add to the template
 sub tt_vars { ( foo => "bar" ); }
 # Put template in DATA section (or use file with ttfile producer arg)
 Database: [% schema.database %]
 Foo: $foo


A base class producer designed to be sub-classed to create new TT based producers cheaply - by simply giving the template to use and sprinkling in some extra template variables and config.

You can find an introduction to this module in the SQL::Translator::Manual manpage.

The 1st thing the module does is convert the produce sub routine call we get from SQL::Translator into a method call on an object, which we can then sub-class. This is done with the following code which needs to appear in all sub classes.

 # Convert produce call into an object method call
 sub produce { return __PACKAGE__->new( translator => shift )->run; };

See PRODUCER OBJECT below for details.

The upshot of this is we can make new template producers by sub classing this base class, adding the above snippet and a template. The module also provides a number of hooks into the templating process, see SUB CLASS HOOKS for details.

See the SYNOPSIS above for an example of creating a simple producer using a single template stored in the producers DATA section.


Sub-classes can override these methods to control the templating by giving the template source, adding variables and giving config to the Tempate object.


 sub tt_config { ( INTERPOLATE => 1 ); }

Return hash of Template config to add to that given to the the Template manpage new method.


 sub tt_schema { "foo.tt"; }
 sub tt_schema { local $/ = undef; \<DATA>; }

The template to use, return a file name or a scalar ref of TT source, or an the IO::Handle manpage. See the Template manpage for details, as the return from this is passed on to it's produce method.

The default implimentation uses the producer arg ttfile as a filename to read the template from. If the arg isn't there it will look for a __DATA__ section in the class, reading it as template source if found. Returns undef if both these fail, causing the produce call to fail with a 'no template!' error.


 sub tt_vars { ( foo => "bar" ); }

Return hash of template vars to use in the template. Nothing added here by default, but see the tt_default_vars manpage for the variables you get for free.


Return a hash-ref of the default vars given to the template. You wouldn't normally over-ride this, just inherit the default implimentation, to get the translator & schema variables, then over-ride the tt_vars manpage to add your own.

The current default variables are:

The schema to template.

The the SQL::Translator manpage object.


WARNING: This method is Experimental so may change!

Called with the the SQL::Translator::Schema manpage object and should return one (it doesn't have to be the same one) that will become the schema varibale used in the template.

Gets called from tt_default_vars.


The rest of the methods in the class set up a sub-classable producer object. You normally just inherit them.


 my $tt_producer = TT::Base->new( translator => $translator );

Construct a new TT Producer object. Takes a single, named arg of the the SQL::Translator manpage object running the translation. Dies if this is not given.


Return the the SQL::Translator manpage object.


Return the the SQL::Translator::Schema manpage we are translating. This is equivilent to $tt_producer->translator->schema.


Called to actually produce the output, calling the sub class hooks. Returns the produced text.


Util wrapper method around TT::Base->translator->producer_args for (mostley) readonly access to the producer args. How it works depends on the number of arguments you give it and the context.

 No args - Return hashref (the actual hash in Translator) or hash of args.
 1 arg   - Return value of the arg with the passed name.
 2+ args - List of names. In list context returns values of the given arg
           names, returns as a hashref in scalar context. Any names given
           that don't exist in the args are returned as undef.

This is still a bit messy but is a handy way to access the producer args when you use your own to drive the templating.


the perl manpage, the SQL::Translator manpage, the Template manpage.


- Add support for a sqlf template repository, set as an INCLUDE_PATH, so that sub-classes can easily include file based templates using relative paths.

- Pass in template vars from the producer args and command line.

- Merge in TT::Table.

- Hooks to pre-process the schema and post-process the output.


Mark Addison <grommit@users.sourceforge.net>.

 SQL::Translator::Producer::TT::Base - TT based Producer base class.