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1 | package SQL::Translator::Producer::TT::Base; |
2 | |
3 | # ------------------------------------------------------------------- |
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4 | # $Id: Base.pm,v 1.6 2004-08-20 00:58:35 grommit Exp $ |
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5 | # ------------------------------------------------------------------- |
6 | # Copyright (C) 2002-4 SQLFairy Authors |
7 | # |
8 | # This program is free software; you can redistribute it and/or |
9 | # modify it under the terms of the GNU General Public License as |
10 | # published by the Free Software Foundation; version 2. |
11 | # |
12 | # This program is distributed in the hope that it will be useful, but |
13 | # WITHOUT ANY WARRANTY; without even the implied warranty of |
14 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
15 | # General Public License for more details. |
16 | # |
17 | # You should have received a copy of the GNU General Public License |
18 | # along with this program; if not, write to the Free Software |
19 | # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
20 | # 02111-1307 USA |
21 | # ------------------------------------------------------------------- |
22 | |
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23 | =pod |
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24 | |
25 | =head1 NAME |
26 | |
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27 | SQL::Translator::Producer::TT::Base - TT (Template Toolkit) based Producer base |
28 | class. |
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29 | |
30 | =cut |
31 | |
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32 | use strict; |
33 | |
34 | use vars qw[ $VERSION @EXPORT_OK ]; |
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35 | $VERSION = sprintf "%d.%02d", q$Revision: 1.6 $ =~ /(\d+)\.(\d+)/; |
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36 | |
37 | use Template; |
38 | use Data::Dumper; |
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39 | use IO::Handle; |
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40 | use Exporter; |
41 | use base qw(Exporter); |
42 | @EXPORT_OK = qw(produce); |
43 | |
44 | use SQL::Translator::Utils 'debug'; |
45 | |
46 | # Hack to convert the produce call into an object. ALL sub-classes need todo |
47 | # this so that the correct class gets created. |
48 | sub produce { |
49 | return __PACKAGE__->new( translator => shift )->run; |
50 | }; |
51 | |
52 | sub new { |
53 | my $proto = shift; |
54 | my $class = ref $proto || $proto; |
55 | my %args = @_; |
56 | |
57 | my $me = bless {}, $class; |
58 | $me->{translator} = delete $args{translator} || die "Need a translator."; |
59 | |
60 | return $me; |
61 | } |
62 | |
63 | sub translator { shift->{translator}; } |
64 | sub schema { shift->{translator}->schema(@_); } |
65 | |
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66 | # Util args access method. |
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67 | # No args - Return hashref (the actual hash in Translator) or hash of args. |
68 | # 1 arg - Return that named args value. |
69 | # Args - List of names. Return values of the given arg names in list context |
70 | # or return as hashref in scalar context. Any names given that don't |
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71 | # exist in the args are returned as undef. |
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72 | sub args { |
73 | my $me = shift; |
74 | |
75 | # No args |
76 | unless (@_) { |
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77 | return wantarray |
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78 | ? %{ $me->{translator}->producer_args } |
79 | : $me->{translator}->producer_args |
80 | ; |
81 | } |
82 | |
83 | # 1 arg. Return the value whatever the context. |
84 | return $me->{translator}->producer_args->{$_[0]} if @_ == 1; |
85 | |
86 | # More args so return values list or hash ref |
87 | my %args = %{ $me->{translator}->producer_args }; |
88 | return wantarray ? @args{@_} : { map { ($_=>$args{$_}) } @_ }; |
89 | } |
90 | |
91 | # Run the produce and return the result. |
92 | sub run { |
93 | my $me = shift; |
94 | my $scma = $me->schema; |
95 | my %args = %{$me->args}; |
96 | my $tmpl = $me->tt_schema or die "No template!"; |
97 | |
98 | debug "Processing template $tmpl\n"; |
99 | my $out; |
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100 | my $tt = Template->new( |
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101 | #DEBUG => $me->translator->debug, |
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102 | ABSOLUTE => 1, # Set so we can use from the command line sensibly |
103 | RELATIVE => 1, # Maybe the cmd line code should set it! Security! |
104 | $me->tt_config, # Hook for sub-classes to add config |
105 | %args, # Allow any TT opts to be passed in the producer_args |
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106 | ) || die "Failed to initialize Template object: ".Template->error; |
107 | |
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108 | $tt->process( $tmpl, { |
109 | $me->tt_default_vars, |
110 | $me->tt_vars, # Sub-class hook for adding vars |
111 | }, \$out ) |
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112 | or die "Error processing template '$tmpl': ".$tt->error; |
113 | |
114 | return $out; |
115 | } |
116 | |
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117 | |
118 | # Sub class hooks |
119 | #----------------------------------------------------------------------------- |
120 | |
121 | sub tt_config { () }; |
122 | |
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123 | sub tt_schema { |
124 | my $me = shift; |
125 | my $class = ref $me; |
126 | |
127 | my $file = $me->args("ttfile"); |
128 | return $file if $file; |
129 | |
130 | no strict 'refs'; |
131 | my $ref = *{"$class\:\:DATA"}{IO}; |
132 | if ( $ref->opened ) { |
133 | local $/ = undef; # Slurp mode |
134 | return \<$ref>; |
135 | } |
136 | |
137 | undef; |
138 | }; |
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139 | |
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140 | sub tt_default_vars { |
141 | my $me = shift; |
142 | return ( |
143 | translator => $me->translator, |
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144 | schema => $me->pre_process_schema($me->translator->schema), |
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145 | ); |
146 | } |
147 | |
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148 | sub pre_process_schema { $_[1] } |
149 | |
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150 | sub tt_vars { () }; |
151 | |
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152 | 1; |
153 | |
154 | # ------------------------------------------------------------------- |
155 | |
156 | =pod |
157 | |
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158 | =head1 SYNOPSIS |
159 | |
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160 | # Create a producer using a template in the __DATA__ section. |
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161 | package SQL::Translator::Producer::Foo; |
162 | |
163 | use base qw/SQL::Translator::Producer::TT::Base/; |
164 | |
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165 | # Convert produce call into a method call on our new class |
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166 | sub produce { return __PACKAGE__->new( translator => shift )->run; }; |
167 | |
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168 | # Configure the Template object. |
169 | sub tt_config { ( INTERPOLATE => 1 ); } |
170 | |
171 | # Extra vars to add to the template |
172 | sub tt_vars { ( foo => "bar" ); } |
173 | |
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174 | # Put template in DATA section (or use file with ttfile producer arg) |
175 | __DATA__ |
176 | Schema |
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177 | |
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178 | Database: [% schema.database %] |
179 | Foo: $foo |
180 | ... |
181 | |
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182 | =head1 DESCRIPTION |
183 | |
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184 | A base class producer designed to be sub-classed to create new TT based |
185 | producers cheaply - by simply giving the template to use and sprinkling in some |
186 | extra template variables and config. |
187 | |
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188 | You can find an introduction to this module in L<SQL::Translator::Manual>. |
189 | |
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190 | The 1st thing the module does is convert the produce sub routine call we get |
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191 | from SQL::Translator into a method call on an object, which we can then |
192 | sub-class. This is done with the following code which needs to appear in B<all> |
193 | sub classes. |
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194 | |
195 | # Convert produce call into an object method call |
196 | sub produce { return __PACKAGE__->new( translator => shift )->run; }; |
197 | |
198 | See L<PRODUCER OBJECT> below for details. |
199 | |
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200 | The upshot of this is we can make new template producers by sub classing this |
201 | base class, adding the above snippet and a template. |
202 | The module also provides a number of hooks into the templating process, |
203 | see L<SUB CLASS HOOKS> for details. |
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204 | |
205 | See the L<SYNOPSIS> above for an example of creating a simple producer using |
206 | a single template stored in the producers DATA section. |
207 | |
208 | =head1 SUB CLASS HOOKS |
209 | |
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210 | Sub-classes can override these methods to control the templating by giving |
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211 | the template source, adding variables and giving config to the Tempate object. |
212 | |
213 | =head2 tt_config |
214 | |
215 | sub tt_config { ( INTERPOLATE => 1 ); } |
216 | |
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217 | Return hash of Template config to add to that given to the L<Template> C<new> |
218 | method. |
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219 | |
220 | =head2 tt_schema |
221 | |
222 | sub tt_schema { "foo.tt"; } |
223 | sub tt_schema { local $/ = undef; \<DATA>; } |
224 | |
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225 | The template to use, return a file name or a scalar ref of TT |
226 | source, or an L<IO::Handle>. See L<Template> for details, as the return from |
227 | this is passed on to it's C<produce> method. |
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228 | |
229 | The default implimentation uses the producer arg C<ttfile> as a filename to read |
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230 | the template from. If the arg isn't there it will look for a C<__DATA__> section |
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231 | in the class, reading it as template source if found. Returns undef if both |
232 | these fail, causing the produce call to fail with a 'no template!' error. |
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233 | |
234 | =head2 tt_vars |
235 | |
236 | sub tt_vars { ( foo => "bar" ); } |
237 | |
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238 | Return hash of template vars to use in the template. Nothing added here |
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239 | by default, but see L<tt_default_vars> for the variables you get for free. |
240 | |
241 | =head2 tt_default_vars |
242 | |
243 | Return a hash-ref of the default vars given to the template. |
244 | You wouldn't normally over-ride this, just inherit the default implimentation, |
245 | to get the C<translator> & C<schema> variables, then over-ride L<tt_vars> to add |
246 | your own. |
247 | |
248 | The current default variables are: |
249 | |
250 | =over 4 |
251 | |
252 | =item schema |
253 | |
254 | The schema to template. |
255 | |
256 | =item translator |
257 | |
258 | The L<SQL::Translator> object. |
259 | |
260 | =back |
261 | |
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262 | =head2 pre_process_schema |
263 | |
264 | WARNING: This method is Experimental so may change! |
265 | |
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266 | Called with the L<SQL::Translator::Schema> object and should return one (it |
267 | doesn't have to be the same one) that will become the C<schema> varibale used |
268 | in the template. |
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269 | |
270 | Gets called from tt_default_vars. |
271 | |
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272 | =head1 PRODUCER OBJECT |
273 | |
274 | The rest of the methods in the class set up a sub-classable producer object. |
275 | You normally just inherit them. |
276 | |
277 | =head2 new |
278 | |
279 | my $tt_producer = TT::Base->new( translator => $translator ); |
280 | |
281 | Construct a new TT Producer object. Takes a single, named arg of the |
282 | L<SQL::Translator> object running the translation. Dies if this is not given. |
283 | |
284 | =head2 translator |
285 | |
286 | Return the L<SQL::Translator> object. |
287 | |
288 | =head2 schema |
289 | |
290 | Return the L<SQL::Translator::Schema> we are translating. This is equivilent |
291 | to C<< $tt_producer->translator->schema >>. |
292 | |
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293 | =head2 run |
294 | |
295 | Called to actually produce the output, calling the sub class hooks. Returns the |
296 | produced text. |
297 | |
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298 | =head2 args |
299 | |
300 | Util wrapper method around C<< TT::Base->translator->producer_args >> for |
301 | (mostley) readonly access to the producer args. How it works depends on the |
302 | number of arguments you give it and the context. |
303 | |
304 | No args - Return hashref (the actual hash in Translator) or hash of args. |
305 | 1 arg - Return value of the arg with the passed name. |
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306 | 2+ args - List of names. In list context returns values of the given arg |
307 | names, returns as a hashref in scalar context. Any names given |
308 | that don't exist in the args are returned as undef. |
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309 | |
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310 | This is still a bit messy but is a handy way to access the producer args when |
311 | you use your own to drive the templating. |
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312 | |
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313 | =head1 SEE ALSO |
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314 | |
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315 | L<perl>, |
316 | L<SQL::Translator>, |
317 | L<Template>. |
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318 | |
319 | =head1 TODO |
320 | |
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321 | - Add support for a sqlf template repository, set as an INCLUDE_PATH, |
322 | so that sub-classes can easily include file based templates using relative |
323 | paths. |
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324 | |
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325 | - Pass in template vars from the producer args and command line. |
326 | |
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327 | - Merge in TT::Table. |
328 | |
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329 | - Hooks to pre-process the schema and post-process the output. |
330 | |
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331 | =head1 AUTHOR |
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332 | |
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333 | Mark Addison E<lt>grommit@users.sourceforge.netE<gt>. |
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334 | |
335 | =cut |