caschat.php

<?php
// This file is part of Stack - http://stack.maths.ed.ac.uk/
//
// Stack is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Stack 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Stack.  If not, see <http://www.gnu.org/licenses/>.

/**
 * This script lets the user send commands to the Maxima, and see the response.
 * This can be useful for learning about the CAS syntax, and also for testing
 * that maxima is working correctly.
 *
 * @copyright  2012 University of Birmingham
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

require_once(__DIR__.'/../../../config.php');

require_once($CFG->libdir . '/questionlib.php');
require_once(__DIR__ . '/locallib.php');
require_once(__DIR__ . '/stack/utils.class.php');
require_once(__DIR__ . '/stack/options.class.php');
require_once(__DIR__ . '/stack/cas/castext.class.php');
require_once(__DIR__ . '/stack/cas/casstring.class.php');
require_once(__DIR__ . '/stack/cas/cassession.class.php');
require_once(__DIR__ . '/stack/cas/keyval.class.php');


// Get the parameters from the URL.
$questionid = optional_param('questionid', null, PARAM_INT);

if (!$questionid) {
    require_login();
    $context = context_system::instance();
    require_capability('qtype/stack:usediagnostictools', $context);
    $urlparams = array();

} else {
    // Load the necessary data.
    $questiondata = $DB->get_record('question', array('id' => $questionid), '*', MUST_EXIST);
    $question = question_bank::load_question($questionid);

    // Process any other URL parameters, and do require_login.
    list($context, $seed, $urlparams) = qtype_stack_setup_question_test_page($question);

    // Check permissions.
    question_require_capability_on($questiondata, 'view');
}

$context = context_system::instance();
$PAGE->set_context($context);
$PAGE->set_url('/question/type/stack/caschat.php', $urlparams);
$title = stack_string('chattitle');
$PAGE->set_title($title);


$debuginfo = '';
$errs = '';
$varerrs = '';

$vars   = optional_param('vars', '', PARAM_RAW);
$string = optional_param('cas', '', PARAM_RAW);
$simp   = optional_param('simp', '', PARAM_RAW);

// Always fix dollars in this script.
// Very useful for converting existing text for use elswhere in Moodle, such as in pages of text.
$string = stack_maths::replace_dollars($string);

// Sort out simplification.
if ('on' == $simp) {
    $simp = true;
} else {
    $simp = false;
}
// Initially simplification should be on.
if (!$vars and !$string) {
    $simp = true;
}

// Set a value for the "insert stars" flag.  Useful for testing, but should be set to zero normally.
$stars = 0;

if ($string) {
    $options = new stack_options();
    $options->set_site_defaults();
    $options->set_option('simplify', $simp);

    $session = new stack_cas_session(null, $options);
    if ($vars) {
        $keyvals = new stack_cas_keyval($vars, $options, 0, 't', true, $stars);
        $session = $keyvals->get_session();
        $varerrs = $keyvals->get_errors();
    }

    if (!$varerrs) {
        $ct           = new stack_cas_text($string, $session, 0, 't', true, $stars);
        $displaytext  = $ct->get_display_castext();
        $errs         = $ct->get_errors();
        $debuginfo    = $ct->get_debuginfo();
    }
}

echo $OUTPUT->header();
echo $OUTPUT->heading($title);
echo html_writer::tag('p', stack_string('chatintro'));

// If we are editing the General Feedback from a question it is very helpful to see the question text.
if ($questionid) {
    echo $OUTPUT->heading(stack_string('questiontext'), 3);
    echo html_writer::tag('pre', $question->questiontext, array('class' => 'questiontext'));
}

if (!$varerrs) {
    if ($string) {
        echo $OUTPUT->box(stack_ouput_castext($displaytext));
    }
}

if ($simp) {
    $simp = stack_string('autosimplify').' '.
                html_writer::empty_tag('input', array('type' => 'checkbox', 'checked' => $simp, 'name' => 'simp'));
} else {
    $simp = stack_string('autosimplify').' '.html_writer::empty_tag('input', array('type' => 'checkbox', 'name' => 'simp'));
}

$varlen = substr_count($vars, "\n") + 3;
$stringlen = max(substr_count($string, "\n") + 3, 8);

echo html_writer::tag('form',
            html_writer::tag('h2', stack_string('questionvariables')) .
            html_writer::tag('p', $varerrs) .
            html_writer::tag('p', html_writer::tag('textarea', $vars,
                    array('cols' => 100, 'rows' => $varlen, 'name' => 'vars'))) .
            html_writer::tag('p', $simp) .
            html_writer::tag('h2', stack_string('castext')) .
            html_writer::tag('p', $errs) .
            html_writer::tag('p', html_writer::tag('textarea', $string,
                    array('cols' => 100, 'rows' => $stringlen, 'name' => 'cas'))) .
            html_writer::tag('p', html_writer::empty_tag('input',
                    array('type' => 'submit', 'value' => stack_string('chat')))),
        array('action' => $PAGE->url, 'method' => 'post'));

if ($string) {
    // Display the question variables.
    echo $OUTPUT->heading(stack_string('questionvariablevalues'), 3);
    echo html_writer::start_tag('div', array('class' => 'questionvariables'));
    $variables = $session->get_keyval_representation();
    $variables = implode(";\n", explode('; ', $variables));
    if (trim($variables) == '') {
        $variables .= get_string('none');
    }
    echo  html_writer::tag('pre', $variables);
    echo html_writer::end_tag('div');
}

if ('' != trim($debuginfo)) {
    echo $OUTPUT->box($debuginfo);
}

echo $OUTPUT->footer();