diff options
Diffstat (limited to 'parser.php')
| -rw-r--r-- | parser.php | 45 |
1 files changed, 22 insertions, 23 deletions
@@ -52,7 +52,9 @@ function qtype_algebra_parser_strlen_sort($a, $b) { $alen = strlen($a); $blen = strlen($b); // If the two lengths are equal return zero. - if ($alen == $blen) return 0; + if ($alen == $blen) { + return 0; + } // Otherwise return +1 if a > b or -1 if a < b. return ($alen > $blen) ? -1 : +1; } @@ -66,7 +68,11 @@ function qtype_algebra_parser_strlen_sort($a, $b) { * variable. Each type of term implements a subclass of this base class. */ class qtype_algebra_parser_term { - + // Member variables. + public var $_value; // String of the actual term itself. + public var $_arguments = array(); // Array of arguments in class form. + public var $_formats; // Array of format strings. + public var $_nargs; // Number of arguments for this term. /** * Constructor for the generic parser term. * @@ -99,7 +105,7 @@ class qtype_algebra_parser_term { * @return array of the arguments that, with a format string, can be passed to sprintf */ public function print_args($method) { - // Create an empty array to store the arguments in + // Create an empty array to store the arguments in. $args = array(); // Handle zero argument terms differently by making the // first 'argument' the value of the term itself. @@ -208,7 +214,7 @@ class qtype_algebra_parser_term { * @param $args array to set the arguments of the term to */ public function set_arguments($args) { - if (count($args)!= $this->_nargs) { + if (count($args) != $this->_nargs) { throw new Exception(get_string('nargswrong', 'qtype_algebra', $this->_value)); } $this->_arguments = $args; @@ -228,7 +234,7 @@ class qtype_algebra_parser_term { public function check_arguments($exc = true) { $retval = (count($this->_arguments) == $this->_nargs); if ($exc && !$retval) { - throw new Exception(get_string('nargswrong', 'qtype_algebra', $this->_value)); + throw new Exception(get_string('nargswrong', 'qtype_algebra', $this->_value)); } else { return $retval; } @@ -345,11 +351,10 @@ class qtype_algebra_parser_term { $this->_arguments[1]->equivalent($expr->_arguments[1])) { // Both arguments are equivalent so we have a match. return true; - } - // Otherwise if the operator commutes we can see if the first argument matches - // the second argument and vice versa. - else if ($this->_commutes and $this->_arguments[0]->equivalent($expr->_arguments[1]) and + } else if ($this->_commutes and $this->_arguments[0]->equivalent($expr->_arguments[1]) and $this->_arguments[1]->equivalent($expr->_arguments[0])) { + // Otherwise if the operator commutes we can see if the first argument matches + // the second argument and vice versa. return true; } else { return false; @@ -418,12 +423,6 @@ class qtype_algebra_parser_term { public function __toString() { return '<Algebraic parser term of type \''.get_class($this).'\'>'; } - - // Member variables. - var $_value; // String of the actual term itself. - var $_arguments = array(); // Array of arguments in class form. - var $_formats; // Array of format strings. - var $_nargs; // Number of arguments for this term. } /** @@ -604,7 +603,7 @@ class qtype_algebra_parser_number extends qtype_algebra_parser_term { */ class qtype_algebra_parser_variable extends qtype_algebra_parser_term { // Define the list of variable names which will be replaced by greek letters - public static $greek = array ( + public static $greek = array ( 'alpha', 'beta', 'gamma', @@ -655,23 +654,23 @@ 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 ($this->_subscript[0] == '_') { $this->_subscript = substr($this->_subscript, 1); } // Call the base class constructor with the variable text set to the combination of the // base name and the subscript without an underscore between them. parent::__construct(self::NARGS, self::$formats['greek'], $this->_base.$this->_subscript); - } - // Otherwise we have a simple multi-letter variable name. Treat the fist letter as the base - // name and the rest as the subscript. - else { + } else { + // Otherwise we have a simple multi-letter variable name. Treat the fist letter as the base + // name and the rest as the subscript. + // Get the variable's base name. $this->_base = substr($text, 0, 1); // Now set the subscript to the remaining letters. $this->_subscript = substr($text, 1); // If the first letter of the subscript is an underscore then remove it. - if ($this->_subscript[0] == '_') { + if ($this->_subscript[0] == '_') { $this->_subscript = substr($this->_subscript, 1); } // Call the base class constructor with the variable text set to the combination of the @@ -1708,7 +1707,7 @@ class qtype_algebra_parser { } else { throw new Exception(get_string('missingonearg', 'qtype_algebra', $op)); } - } elseif ($tree[$i]->n_args() == 2) { + } elseif ($tree[$i]->n_args() == 2) { if ($i > 0 and $i < (count($tree)-1)) { $tree[$i]->set_arguments(array($tree[$i-1], $tree[$i+1])); |