changed licence to lgpl, metaform includes wfpl in tarbal

[wfpl.git] / template.php

<?php

#  Copyright (C) 2005 Jason Woofenden
#
#  This file is part of wfpl.
#
#  wfpl is free software; you can redistribute it and/or modify it under the
#  terms of the GNU Lesser General Public License as published by the Free
#  Software Foundation; either version 2.1 of the License, or (at your option)
#  any later version.
#
#  wfpl is distributed in the hope that it will be useful, but WITHOUT ANY
#  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
#  FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for
#  more details.
#
#  You should have received a copy of the GNU Lesser General Public License
#  along with wfpl; if not, write to the Free Software Foundation, Inc., 51
#  Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA


# This file contains generally useful template handling code. It is wrapped in
# an object so that if you want/need to you can make more than one instance of
# it and they won't step on each other's toes. Also there are a set of global
# functions at the bottom so you don't have to mess around with objects if you
# don't want to. The documentation will be on the object methods, but just know
# that each has a straight function wrapper at the bottom with 'tem_' prepended
# to the name.

# This is designed to be as simple as it can be for your project. The simple
# way to use it is to set some key/value pairs with tem_set() then call
# tem_output('filename.html') to output the page. A more complex example
# including the use of sub-templates can be found in tem_test.php

# FIXME: sub-sub templates need to be cleared when the sub template containing
# them is run

require_once('code/wfpl/encode.php');
require_once('code/wfpl/misc.php'); # to get read_whole_file()

class tem {
        var $keyval;        # an array containing key/value pairs 
        var $filename;      # template filename (sometimes not set)
        var $template;      # contents of template
        var $sub_templates; # tag-name/template-string pairs
        var $sub_subs;      # key: sub-template name  value: array of names of the sub-templates of this one

        # initialize variables
        function tem() {
                $this->keyval = array('' => '~'); # so that ~~ in the template creates a single ~
                $this->sub_templates = array();
        }

        # set a key/value pair. if a ~tag~ in the template matches key it will be replaced by value
        function set($key, $value) {
                $this->keyval[$key] = $value;
        }

        # clear a value. Functionally equivalent to set($key, '') but cleaner and more efficient
        function clear($key) {
                unset($this->keyval[$key]);
        }

        # grab a value you stuck in earlier with set()
        function get($key) {
                return $this->keyval[$key];
        }

        # run the template engine on one of the sub-templates and append the result
        # to the keyval in the main array. See tem_test.php for an example of how
        # this can be used.
        function sub($sub_template_name) {
                $this->keyval[$sub_template_name] .= template_run($this->sub_templates[$sub_template_name], $this->keyval);

                # after running a sub-template, clear its sub-templates
                if(isset($this->sub_subs[$sub_template_name])) {
                        foreach($this->sub_subs[$sub_template_name] as $sub_sub) {
                                $this->clear($sub_sub);
                        }
                }
        }

        # this is used by tem::load() and should be otherwise useless
        function _load(&$in, &$out, &$parents, &$parent) {
                while($in) {
                        # scan for one of: 1) the begining of a sub-template 2) the end of this one 3) the end of the file
                        $n = strpos($in, '<!--~');
                        if($n === false) { # not found
                                # we hit the end of the file
                                $out .= $in;
                                $in = '';
                                return;
                        }

                        # move everything up to (but not including) <!-- to the output
                        $out .= substr($in, 0, $n);
                        $in = substr($in, $n);

                        # we found something.
                        # is it an end tag?
                        if(strcmp('<!--~end~-->', substr($in, 0, 12)) == 0) {
                                $in = substr($in, 12);
                                $parent = array_pop($parents);
                                return;
                        }

                        $matches = array();
                        # this limits sub_template names to 50 chars
                        if(ereg('^<!--~([^~]*) start~-->', substr($in, 0, 65), $matches)) {
                                list($start_tag, $tag_name) = $matches;

                                # keep track of the tree
                                if(!isset($this->sub_subs[$parent])) {
                                        $this->sub_subs[$parent] = array();
                                }
                                array_push($this->sub_subs[$parent], $tag_name);
                                array_push($parents, $parent);
                                $parent = $tag_name;

                                $out .= '~' . $tag_name . '~';
                                $in = substr($in, strlen($start_tag));
                                $this->sub_templates[$tag_name] = '';
                                $this->_load($in, $this->sub_templates[$tag_name], $parents, $parent);
                        } else {
                                # it's not a start tag or end tag, so let's pass it through:
                                $out .= substr($in, 0, 5);
                                $in = substr($in, 5);
                        }
                } #repeat
        }

        # This is useful when you have sub-templates that you want to mess with
        # before the main template is run. But can also be used to simply specify
        # the filename ahead of time.
        function load($filename) {
                $this->filename = $filename;
                $tmp = read_whole_file($filename);
                $this->template = '';
                $parents = array('top_level_subs' => array());
                $parent = 'top_level_subs';
                $this->_load($tmp, $this->template, $parents, $parent);
        }
                
        # Run the template. Pass a filename, or a string, unless you've already
        # specified a template with load()
        function run($templ = false) {
                if($templ !== false) {
                        if(strlen($templ) < 150 && file_exists($templ)) {
                                $this->filename = $templ;
                                unset($this->template);
                        } else {
                                $this->template = $templ;
                        }
                }

                if(!$this->template) {
                        if(!$this->filename) {
                                print "sorry, no template to run\n";
                                exit(1);
                        }

                        $this->template = read_whole_file($this->filename);
                }
                
                return template_run($this->template, $this->keyval);
        }       

        # same as run() except the output is print()ed
        function output($templ = false) {
                print($this->run($templ));
        }
}

# Below are functions so you can use the above class without allocating or
# keeping track of it.

# get a reference to the current template object
function tem_init() { 
        if(!$GLOBALS['wfpl_template']) {
                $GLOBALS['wfpl_template'] = new tem();
        }
}
                
function tem_set($key, $value) {
        tem_init();
        $GLOBALS['wfpl_template']->set($key, $value);
}
        
function tem_get($key) {
        tem_init();
        return $GLOBALS['wfpl_template']->get($key);
}

function tem_run($templ = false) {
        tem_init();
        return $GLOBALS['wfpl_template']->run($templ);
}

function tem_sub($sub_template_name) {
        tem_init();
        $GLOBALS['wfpl_template']->sub($sub_template_name);
}

function tem_load($filename) {
        tem_init();
        $GLOBALS['wfpl_template']->load($filename);
}

function tem_output($filename = false) {
        tem_init();
        $GLOBALS['wfpl_template']->output($filename);
}



# this is used in template_run() and should be of no other use
function template_filler($matches) {
        list($tag, $enc) = explode('.', $matches[1], 2);
        $value = $GLOBALS['wfpl_template_keyval'][$tag];
        if($enc) {
                $encs = explode('.', $enc);
                foreach($encs as $enc) {
                        $enc = "enc_$enc";
                        if(function_exists($enc)) {
                                $value = $enc($value);
                        } else {
                                print "ERROR: encoder function '$enc' not found.<br>\n";
                                exit(1);
                        }
                }
        }
        return $value;
}


# pass a template string and an associative array of the key/values and it
# returns the result.
function template_run($template, &$keyval) {
        $GLOBALS['wfpl_template_keyval'] =& $keyval;
        return preg_replace_callback(array('|<!--~([^~]*)~-->|', '|~([^~]*)~|', '|<span class="template">([^<]*)</span>|', '|<p class="template">([^<]*)</p>|'), 'template_filler', $template);
}


?>