diff options
Diffstat (limited to 'parser.php')
| -rw-r--r-- | parser.php | 42 |
1 files changed, 17 insertions, 25 deletions
@@ -21,20 +21,9 @@ defined('MOODLE_INTERNAL') || die(); -// From the PHP manual: check for the existance of lcfirst and -// if not found create one. -if (!function_exists('lcfirst')) { - /** - * Make a string's first character lowercase - * - * @param string $str - * @return string the resulting string. - */ - function lcfirst( $str ) { - $str[0] = strtolower($str[0]); - return (string)$str; - } -} +require_once(__DIR__.'/../../../config.php'); + +require_login(); /** * Helper function which will compare two strings using their length only. @@ -42,20 +31,22 @@ if (!function_exists('lcfirst')) { * This function is intended for use in sorting arrays of strings by their string * length. This is used to order arrays for regular expressions so that the longest * expressions are checked first. + * In this version, if both strings have equal length, string order is used. So this + * version of the sort is stable. * * @param $a first string to compare * @param $b second string to compare - * @return -1 if $a is longer than $b, 0 if they are the same length and +1 if $a is shorter + * @return -1 if $a is longer than $b, and +1 if $a is shorter */ function qtype_algebra_parser_strlen_sort($a, $b) { // Get the two string lengths once so we don't have to repeat the function call. $alen = strlen($a); $blen = strlen($b); - // If the two lengths are equal return zero. + // If the two lengths are equal use strings order. if ($alen == $blen) { - return 0; + return ($a > $b) ? -1 : +1; } - // Otherwise return +1 if a > b or -1 if a < b. + // Otherwise return +1 if a is shorter or -1 if longer. return ($alen > $blen) ? -1 : +1; } @@ -73,6 +64,7 @@ class qtype_algebra_parser_term { public $_arguments = array(); // Array of arguments in class form. public $_formats; // Array of format strings. public $_nargs; // Number of arguments for this term. + /** * Constructor for the generic parser term. * @@ -434,7 +426,8 @@ class qtype_algebra_parser_term { * throw an exception in such cases. */ class qtype_algebra_parser_nullterm extends qtype_algebra_parser_term { - + /** @var The TeX multiply operator. */ + public $id; /** * Constructs an instance of a null term. * @@ -505,7 +498,7 @@ class qtype_algebra_parser_number extends qtype_algebra_parser_term { $this->_base = $m[1]; $this->_exp = $m[2]; $eformats = array('str' => '%sE%s', - 'tex' => '%s \\times 10^{%s}'); + 'tex' => '%s \\' . get_config('qtype_algebra', 'multiplyoperator') . '10^{%s}'); parent::__construct(self::NARGS, $eformats, $text); } else { $this->_base = $text; @@ -654,7 +647,7 @@ class qtype_algebra_parser_variable extends qtype_algebra_parser_term { // Extract the remaining characters for use as the subscript. $this->_subscript = substr($text, strlen($m[1])); // If the first letter of the subscript is an underscore then remove it. - if ($this->_subscript[0] == '_') { + if (strlen($this->_subscript) != 0 && $this->_subscript[0] == '_') { $this->_subscript = substr($this->_subscript, 1); } // Call the base class constructor with the variable text set to the combination of the @@ -879,7 +872,7 @@ class qtype_algebra_parser_multiply extends qtype_algebra_parser_term { */ public function __construct($text) { $this->mformats = array('*' => array('str' => '%s*%s', - 'tex' => '%s \\times %s'), + 'tex' => '%s \\' . get_config('qtype_algebra', 'multiplyoperator') . ' %s'), '.' => array('str' => '%s %s', 'tex' => '%s %s', 'sage' => '%s*%s') @@ -900,7 +893,7 @@ class qtype_algebra_parser_multiply extends qtype_algebra_parser_term { parent::set_arguments($args); // Set the default explicit format. $this->_formats = $this->mformats['*']; - // Only allow the implicit multipication if the second argument is either a + // Only allow the implicit multiplication if the second argument is either a // special, variable, function or bracket and not negative. In all other cases the operator must be // explicitly written. if (is_a($args[1], 'qtype_algebra_parser_bracket') or @@ -918,7 +911,7 @@ class qtype_algebra_parser_multiply extends qtype_algebra_parser_term { // power terms are parsed before multiplication ones and are required to // have two arguments. $powargs = $args[1]->arguments(); - // Allow the implicit multipication if the power's first argument is either a + // Allow the implicit multiplication if the power's first argument is either a // special, variable, function or bracket and not negative. if (is_a($powargs[0], 'qtype_algebra_parser_bracket') or is_a($powargs[0], 'qtype_algebra_parser_variable') or @@ -1728,4 +1721,3 @@ class qtype_algebra_parser { // Sort static arrays once here by inverse string length. usort(qtype_algebra_parser_variable::$greek, 'qtype_algebra_parser_strlen_sort'); usort(qtype_algebra_parser::$functions, 'qtype_algebra_parser_strlen_sort'); - |