1 package SQL::Translator::Producer::TT::Base;
7 SQL::Translator::Producer::TT::Base - TT (Template Toolkit) based Producer base
14 use vars qw[ $VERSION @EXPORT_OK ];
21 use base qw(Exporter);
22 @EXPORT_OK = qw(produce);
24 use SQL::Translator::Utils 'debug';
26 # Hack to convert the produce call into an object. ALL sub-classes need todo
27 # this so that the correct class gets created.
29 return __PACKAGE__->new( translator => shift )->run;
34 my $class = ref $proto || $proto;
37 my $me = bless {}, $class;
38 $me->{translator} = delete $args{translator} || die "Need a translator.";
43 sub translator { shift->{translator}; }
44 sub schema { shift->{translator}->schema(@_); }
46 # Util args access method.
47 # No args - Return hashref (the actual hash in Translator) or hash of args.
48 # 1 arg - Return that named args value.
49 # Args - List of names. Return values of the given arg names in list context
50 # or return as hashref in scalar context. Any names given that don't
51 # exist in the args are returned as undef.
58 ? %{ $me->{translator}->producer_args }
59 : $me->{translator}->producer_args
63 # 1 arg. Return the value whatever the context.
64 return $me->{translator}->producer_args->{$_[0]} if @_ == 1;
66 # More args so return values list or hash ref
67 my %args = %{ $me->{translator}->producer_args };
68 return wantarray ? @args{@_} : { map { ($_=>$args{$_}) } @_ };
71 # Run the produce and return the result.
74 my $scma = $me->schema;
75 my %args = %{$me->args};
76 my $tmpl = $me->tt_schema or die "No template!";
78 debug "Processing template $tmpl\n";
80 my $tt = Template->new(
81 #DEBUG => $me->translator->debug,
82 ABSOLUTE => 1, # Set so we can use from the command line sensibly
83 RELATIVE => 1, # Maybe the cmd line code should set it! Security!
84 $me->tt_config, # Hook for sub-classes to add config
85 %args, # Allow any TT opts to be passed in the producer_args
86 ) || die "Failed to initialize Template object: ".Template->error;
88 $tt->process( $tmpl, {
90 $me->tt_vars, # Sub-class hook for adding vars
92 or die "Error processing template '$tmpl': ".$tt->error;
99 #-----------------------------------------------------------------------------
101 sub tt_config { () };
107 my $file = $me->args("ttfile");
108 return $file if $file;
111 my $ref = *{"$class\:\:DATA"}{IO};
112 if ( $ref->opened ) {
113 local $/ = undef; # Slurp mode
120 sub tt_default_vars {
123 translator => $me->translator,
124 schema => $me->pre_process_schema($me->translator->schema),
128 sub pre_process_schema { $_[1] }
138 # Create a producer using a template in the __DATA__ section.
139 package SQL::Translator::Producer::Foo;
141 use base qw/SQL::Translator::Producer::TT::Base/;
143 # Convert produce call into a method call on our new class
144 sub produce { return __PACKAGE__->new( translator => shift )->run; };
146 # Configure the Template object.
147 sub tt_config { ( INTERPOLATE => 1 ); }
149 # Extra vars to add to the template
150 sub tt_vars { ( foo => "bar" ); }
152 # Put template in DATA section (or use file with ttfile producer arg)
156 Database: [% schema.database %]
162 A base class producer designed to be sub-classed to create new TT based
163 producers cheaply - by simply giving the template to use and sprinkling in some
164 extra template variables and config.
166 You can find an introduction to this module in L<SQL::Translator::Manual>.
168 The 1st thing the module does is convert the produce sub routine call we get
169 from SQL::Translator into a method call on an object, which we can then
170 sub-class. This is done with the following code which needs to appear in B<all>
173 # Convert produce call into an object method call
174 sub produce { return __PACKAGE__->new( translator => shift )->run; };
176 See L<PRODUCER OBJECT> below for details.
178 The upshot of this is we can make new template producers by sub classing this
179 base class, adding the above snippet and a template.
180 The module also provides a number of hooks into the templating process,
181 see L<SUB CLASS HOOKS> for details.
183 See the L<SYNOPSIS> above for an example of creating a simple producer using
184 a single template stored in the producers DATA section.
186 =head1 SUB CLASS HOOKS
188 Sub-classes can override these methods to control the templating by giving
189 the template source, adding variables and giving config to the Tempate object.
193 sub tt_config { ( INTERPOLATE => 1 ); }
195 Return hash of Template config to add to that given to the L<Template> C<new>
200 sub tt_schema { "foo.tt"; }
201 sub tt_schema { local $/ = undef; \<DATA>; }
203 The template to use, return a file name or a scalar ref of TT
204 source, or an L<IO::Handle>. See L<Template> for details, as the return from
205 this is passed on to it's C<produce> method.
207 The default implimentation uses the producer arg C<ttfile> as a filename to read
208 the template from. If the arg isn't there it will look for a C<__DATA__> section
209 in the class, reading it as template source if found. Returns undef if both
210 these fail, causing the produce call to fail with a 'no template!' error.
214 sub tt_vars { ( foo => "bar" ); }
216 Return hash of template vars to use in the template. Nothing added here
217 by default, but see L<tt_default_vars> for the variables you get for free.
219 =head2 tt_default_vars
221 Return a hash-ref of the default vars given to the template.
222 You wouldn't normally over-ride this, just inherit the default implimentation,
223 to get the C<translator> & C<schema> variables, then over-ride L<tt_vars> to add
226 The current default variables are:
232 The schema to template.
236 The L<SQL::Translator> object.
240 =head2 pre_process_schema
242 WARNING: This method is Experimental so may change!
244 Called with the L<SQL::Translator::Schema> object and should return one (it
245 doesn't have to be the same one) that will become the C<schema> varibale used
248 Gets called from tt_default_vars.
250 =head1 PRODUCER OBJECT
252 The rest of the methods in the class set up a sub-classable producer object.
253 You normally just inherit them.
257 my $tt_producer = TT::Base->new( translator => $translator );
259 Construct a new TT Producer object. Takes a single, named arg of the
260 L<SQL::Translator> object running the translation. Dies if this is not given.
264 Return the L<SQL::Translator> object.
268 Return the L<SQL::Translator::Schema> we are translating. This is equivilent
269 to C<< $tt_producer->translator->schema >>.
273 Called to actually produce the output, calling the sub class hooks. Returns the
278 Util wrapper method around C<< TT::Base->translator->producer_args >> for
279 (mostley) readonly access to the producer args. How it works depends on the
280 number of arguments you give it and the context.
282 No args - Return hashref (the actual hash in Translator) or hash of args.
283 1 arg - Return value of the arg with the passed name.
284 2+ args - List of names. In list context returns values of the given arg
285 names, returns as a hashref in scalar context. Any names given
286 that don't exist in the args are returned as undef.
288 This is still a bit messy but is a handy way to access the producer args when
289 you use your own to drive the templating.
299 - Add support for a sqlf template repository, set as an INCLUDE_PATH,
300 so that sub-classes can easily include file based templates using relative
303 - Pass in template vars from the producer args and command line.
305 - Merge in TT::Table.
307 - Hooks to pre-process the schema and post-process the output.
311 Mark Addison E<lt>grommit@users.sourceforge.netE<gt>.