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# Text::CPPTemplate 0.3 |
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# copyright (c) 2000, ETH Zurich |
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# released under the GNU General Public License |
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|
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package Text::CPPTemplate; |
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|
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use strict; |
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|
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use vars qw($VERSION); |
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$VERSION = 0.3; |
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|
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=head1 NAME |
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|
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Text::CPPTemplate - CPP-Style Templates |
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|
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=head1 SYNOPSIS |
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|
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use Text::CPPTemplate; |
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|
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my $templ = new Text::CPPTemplate('/var/web/templates','.html'); |
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|
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print $templ->template({ |
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PAGE => 'index', |
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ELEMENT => 'header', |
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TITLE => 'Test' |
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}); |
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|
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=head1 DESCRIPTION |
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|
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CPPTemplate is a templating system using a CPP-style (C Pre-Processor) syntax. |
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CPPTemplate is quite fast so that it can be used in online Applications such |
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as CGI scripts to separate program the code from the HTML. CPPTemplate is not |
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HTML specific, so it can be used for other applications. For performance |
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reasons, the files containing the templates are read only once and are cached |
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for further use. This is especially handy when working with long running |
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scripts which use the same template over and over again. Apache mod_perl is |
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such an environment. |
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|
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An application can use a large number of templates. They could for example represent |
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different parts of output generated by the aplication. |
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Each template can contain variables and CPP style if-then-else structures. |
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When the template gets activated, all the variables will get substituted |
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and the if-then-else structures will get processed. |
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|
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=head1 FILE NAMES |
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|
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When you activate a template, you do not specify a file-name, but only |
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variables. Based on the contents of some special variables, CPPTemplate will try |
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to load an apropriate template file from disk. It tries to do this using a number of |
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different file-names. The first one to exist will be used. |
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A directory where the templates reside and a suffix have to be specified |
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with the C<new> method. The following list shows which variables cause CPPTemplate to |
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look for which files: |
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|
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=over 4 |
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|
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=item * |
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|
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I<PAGE>B<_>I<ELEMENT> (I<PAGE> and I<ELEMENT> are variables) |
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|
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=item * |
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|
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I<ELEMENT> |
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|
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=item * |
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|
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I<PAGE> |
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|
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=item * |
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|
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C<default> (as is, not a variable) |
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|
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=back |
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|
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In addition, if I<THEME> is specified, the template will be first searched in |
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the subdirectory specified by that variable of the templates directory. |
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|
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In the example given in L<SYNOPSIS>, the following files will be |
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opened in turn until one is found to exist (in the directory F</var/web/templates>): |
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F<index_header.html>, F<header.html>, F<index.html> and F<default.html>. |
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|
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=head1 VARIABLE SUBSTITUTION |
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|
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Variables are marked C<##var##> in the templates. If no variable is found with |
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that specified name, the ##var## text remains unchanged. |
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|
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=head1 CPP-STYLE DIRECTIVES |
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|
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"MiniCPP" directives permit the selection of parts of the template based on |
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some condition. The language is very very basic, it seems to be good-enough |
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for most applications. The following directives are supported: |
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|
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=over 4 |
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|
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=item C<// comment> |
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|
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The whole line is removed from the output |
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|
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=item C<#ifdef VAR> |
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|
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If variable VAR is defined, the following text will be selected. |
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|
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=item C<#if expr> |
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|
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If the expression C<expr> evaluates to true (see L<"EXPRESSIONS">), the |
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following text will be selected. You can use substitutions in the expression |
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with the syntax '##VAR##'. |
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|
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=item C<#elif expr> |
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|
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If the previous C<#if> (or C<#elif>) expression was false, evaluate this |
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C<expr> and if true select the following text. |
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|
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=item C<#else> |
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|
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If the previous C<#if> (or C<#elif>) expression was false, select the following text. |
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|
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=item C<#endif> |
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|
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Ends an C<#ifdef> or an C<#if>. |
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|
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=back |
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|
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Note that these elements can be nested. |
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|
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The newlines will be removed unless two consecutive lines without MiniCPP |
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directives are found. Spaces and tabs will be removed from the beginning and |
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the end of each line. Use '\ ' (backslash space) to insert spaces at the |
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beginning or the end of the line. |
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|
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|
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=head1 EXPRESSIONS |
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|
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At the moment only the following expressions are supported (don't laugh :-)) |
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|
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=over 4 |
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|
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=item A = B |
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|
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If A is equal to B (the text), then the expression is true. |
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|
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=item A ~ B |
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|
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Match A against the regular expression (perl) B. True if it does match, false |
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otherwise. |
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|
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=back |
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|
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=head1 EXAMPLE |
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|
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#if ##ELEMENT## = ruler |
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<HR> |
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#elif ##ELEMENT## = buttons |
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#ifdef ADD_URL |
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<A href="##ADD_URL##">Add</A> |
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#endif |
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#ifdef PREV_URL |
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<A href="##PREV_URL##">Prev</A> |
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#endif |
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#ifdef NEXT_URL |
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<A href="##NEXT_URL##">Next</A> |
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#endif |
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</P> |
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#endif |
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|
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|
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=head1 PER-METHOD DOCUMENTATION |
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|
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=over 4 |
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|
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=cut |
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|
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######## MINI CPP ######### |
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|
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sub _process_if |
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{ |
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my $state= shift; |
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my $expr = shift; |
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|
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my $last_state = $state->[$#$state]; |
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if($expr) { |
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push @$state, $last_state; |
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} |
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else { |
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push @$state, 0; |
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} |
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} |
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|
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sub _substitute |
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{ |
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$_ = shift; |
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my $vars = shift; |
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my $val; |
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s/##(\w+)##/$val=$vars->{$1};defined $val?$val:"##$1##"/ge; |
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return $_; |
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} |
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|
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sub _eval_expr |
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{ |
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my $expr = shift; |
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my $vars = shift; |
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|
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$expr =~ s/^\s+//; $expr =~ s/\s+$//; |
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if($expr =~ /^(.+?)\s*=\s*(.*)$/) { |
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my $a = _substitute($1, $vars); |
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my $b = _substitute($2, $vars); |
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#print "<BR>@@@ $a eq $b ?\n"; |
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return $a eq $b; |
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} |
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elsif($expr =~ /^(.+?)\s*~\s*(.*)$/) { |
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my $a = _substitute($1, $vars); |
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my $b = _substitute($2, $vars); |
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#print "<BR>@@@ $a ~ $b ?\n"; |
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return ($a =~ /$b/); |
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} |
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else { |
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return $expr; |
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} |
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} |
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|
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sub _mini_cpp |
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{ |
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my $self = shift; |
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my $in = shift; |
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my $vars = shift; |
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my $out = ''; |
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|
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my @state = (1); |
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my $line; |
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my $next_linefeed=0; |
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foreach $line (@$in) { |
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#print "@@@@@@ |".join('',@state)."| $line\n"; |
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if($line !~ /^#[a-z]/) { # data |
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if($state[$#state]==1) { |
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$out .= "\n" if $next_linefeed; |
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$out .= _substitute($line,$vars); |
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$next_linefeed=1; |
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} |
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next; |
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} |
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$next_linefeed=0; |
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if($line =~ /^#endif/) { # #endif |
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if($#state<=0) { |
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$out .= "\n!!! SYNTAX ERROR: UNEXPECTED #endif !!!\n"; |
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} |
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else { |
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$#state--; # fast pop :-) |
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} |
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next; |
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} |
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if($line =~ /^#else/) { # #else |
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if($#state<=0) { |
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$out .= "\n!!! SYNTAX ERROR: UNEXPECTED #else !!!\n"; |
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} |
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else { |
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next unless $state[$#state-1]; |
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push @state, pop @state ? 0 : 1; |
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} |
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next; |
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} |
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if($line =~ /^#elif\s+(.+)$/) { # #elif |
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if($#state<=0) { |
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$out .= "\n!!! SYNTAX ERROR: UNEXPECTED #elif !!!\n"; |
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} |
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else { |
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next unless $state[$#state-1]; |
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if($state[$#state]) { |
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$state[$#state] = 2; |
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} |
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else { |
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$#state--; |
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_process_if(\@state, _eval_expr($1,$vars)); |
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} |
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} |
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next; |
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} |
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if($line =~ /^#if\s+(.+?)$/) { # #if |
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_process_if(\@state, $state[$#state] ? _eval_expr($1,$vars) : 0); |
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next; |
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} |
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if($line =~ /^#ifdef\s+(\w+)/) { # #ifdef |
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my $def = $vars->{$1}; |
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_process_if(\@state, ((defined $def) and ($def ne ''))); |
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next; |
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} |
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|
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$out .= "\n!!! SYNTAX ERROR: UNRECOGNIZED TOKEN !!!\n"; |
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} |
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|
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return $out; |
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} |
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|
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####### TEMPLATE ####### |
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|
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sub _slurp_file |
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{ |
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my $self = shift; |
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my $file = shift; |
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|
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#print "<BR>reading $file...<BR>\n"; |
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|
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my $RS_bak = $/; |
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undef $/; |
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open(SLURP, "<$file") or do { |
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return "\n!!! ERROR: couldn't find $file !!!\n"; |
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}; |
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my $data = <SLURP> || ''; |
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close(SLURP); |
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$/=$RS_bak; |
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|
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# replace '\ ' to a special unprobable string |
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$data =~ s/\\ /<<SpAcE>>/g; |
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|
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# trim |
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$data =~ s/^[ \t]+//gm; |
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$data =~ s/[ \t]+$//gm; |
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|
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# replace the forced-space string to a space |
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$data =~ s/<<SpAcE>>/ /g; |
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|
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# strip comments |
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$data =~ s|^//.*||gm; |
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|
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my @ldata = split("\n",$data,-1); |
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return \@ldata; |
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} |
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|
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sub _get_template |
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{ |
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my $self = shift; |
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my $name = shift; |
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|
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my $tdir = $self->{dir}; |
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my $suff = $self->{suff}; |
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|
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if(!exists $self->{cache}{$name}) { |
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my @names = split /\|/, $name; |
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my $ok = 0; |
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my $filename; |
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foreach (@names) { |
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$filename = "$tdir/$_$suff"; |
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if(-r $filename) { |
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$self->{cache}{$name} = $self->_slurp_file($filename); |
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$ok = 1; |
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last; |
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} |
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} |
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if(!$ok) { |
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return ["!!! ERROR: couldn't find a template for $name (t-dir: $tdir) !!!"]; |
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} |
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} |
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|
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return $self->{cache}{$name}; |
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} |
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|
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=item C<new($templates_dir, $suffix)> |
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|
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Create a new CPPTemplate object. C<$templates_dir> is the directory where the templates |
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are stored and C<$suffix> is a text to append to the file-names. |
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|
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=cut |
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|
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sub new { |
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my $proto = shift; |
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my $tdir = shift; |
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my $suff = shift; |
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|
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my $class = ref($proto) || $proto; |
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my $self = {}; |
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|
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$self->{cache} = {}; |
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$self->{dir}=$tdir; |
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$self->{suff}=$suff; |
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|
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bless($self,$class); |
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return $self; |
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} |
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|
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=item C<template(\%vars)> |
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|
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Return a processed template. C<\%vars> is a hashref containing the variables used for building |
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the file-name, for the substitutions and the CPP-style directives. |
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|
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=cut |
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|
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sub template($) |
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{ |
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my $self = shift; |
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my $vars = shift; |
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|
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my $name = $vars->{PAGE}.'_'.$vars->{ELEMENT}.'|'. |
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$vars->{ELEMENT}.'|'. |
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$vars->{PAGE}.'|default'; |
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|
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# themes: |
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if(defined $vars->{THEME}) { |
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$name = $vars->{THEME}.'/'.$vars->{PAGE}.'_'.$vars->{ELEMENT}.'|'. |
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$vars->{THEME}.'/'.$vars->{ELEMENT}.'|'. |
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$vars->{THEME}.'/'.$vars->{PAGE}.'|'. |
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$vars->{THEME}.'/default'.'|'. |
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$name; |
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} |
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my $templ = $self->_get_template($name); |
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my $out = $self->_mini_cpp($templ, $vars); |
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chomp $out; |
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return $out; |
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} |
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|
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1; |
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|
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=back |
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|
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=head1 SEE ALSO |
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|
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Text::TagTemplate(3) |
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|
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=head1 COPYRIGHT |
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|
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Copyright (c) 2000 ETH Zurich, All rights reserved. |
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|
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=head1 LICENSE |
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|
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This program is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 2 of the License, or |
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(at your option) any later version. |
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|
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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|
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You should have received a copy of the GNU General Public License |
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along with this program; if not, write to the Free Software |
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
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This library is free software; you can redistribute it and/or |
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modify it under the terms of the GNU Lesser General Public |
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License as published by the Free Software Foundation; either |
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version 2.1 of the License, or (at your option) any later version. |
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|
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=head1 AUTHOR |
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|
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David Schweikert <dws@ee.ethz.ch>, |
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Tobi Oetiker <oetiker@ee.ethz.ch> |
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