diff options
Diffstat (limited to 'parser.php')
| -rw-r--r-- | parser.php | 124 |
1 files changed, 57 insertions, 67 deletions
@@ -985,8 +985,7 @@ class qtype_algebra_parser_add extends qtype_algebra_parser_term { */ public function evaluate($params) { $this->check_arguments(); - return $this->_arguments[0]->evaluate($params)+ - $this->_arguments[1]->evaluate($params); + return $this->_arguments[0]->evaluate($params) + $this->_arguments[1]->evaluate($params); } // Static class properties. @@ -1032,8 +1031,7 @@ class qtype_algebra_parser_subtract extends qtype_algebra_parser_term { */ public function evaluate($params) { $this->check_arguments(); - return $this->_arguments[0]->evaluate($params)- - $this->_arguments[1]->evaluate($params); + return $this->_arguments[0]->evaluate($params) - $this->_arguments[1]->evaluate($params); } // Static class properties. @@ -1095,9 +1093,9 @@ class qtype_algebra_parser_special extends qtype_algebra_parser_term { } switch($this->_value) { case 'pi': - return $mult*pi(); + return $mult * pi(); case 'e': - return $mult*exp(1); + return $mult * exp(1); default: return 0; } @@ -1199,26 +1197,24 @@ class qtype_algebra_parser_function extends 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('badfuncargs', 'qtype_algebra', $this->_value)); } if (!is_a($args[0], 'qtype_algebra_parser_bracket')) { // Check to see if this function requires a special bracket. if (in_array($this->_value, self::$bracketmap)) { $b = new qtype_algebra_parser_bracket('<'); - } - // Does not require special brackets so create normal ones. - else { + } else { + // Does not require special brackets so create normal ones. $b = new qtype_algebra_parser_bracket('('); } $b->set_arguments($args); $this->_arguments = array($b); - } - // First term already a bracket. - else { + } else { + // First term already a bracket. // Check to see if we need a special bracket. if (in_array($this->_value, self::$bracketmap)) { - // Make the bracket special + // Make the bracket special. $args[0]->make_special(); } // Set the arguments to the given type. @@ -1264,12 +1260,11 @@ class qtype_algebra_parser_function extends qtype_algebra_parser_term { // Check to see if there is an entry to map the function name to a PHP function. if (array_key_exists($this->_value, self::$fnmap)) { $func = self::$fnmap[$this->_value]; - return $mult*$func($this->_arguments[0]->evaluate($params)); - } - // No map entry so the function name must already be a PHP function... - else { + return $mult * $func($this->_arguments[0]->evaluate($params)); + } else { + // No map entry so the function name must already be a PHP function... $tmp = $this->_value; - return $mult*$tmp($this->_arguments[0]->evaluate($params)); + return $mult * $tmp($this->_arguments[0]->evaluate($params)); } } @@ -1301,7 +1296,7 @@ class qtype_algebra_parser_function extends qtype_algebra_parser_term { 'atan' => '\\tan^{-1}', 'sqrt' => '\\sqrt' ); - // List of functions requiring special brackets + // List of functions requiring special brackets. public static $bracketmap = array ('sqrt' ); } @@ -1355,10 +1350,10 @@ class qtype_algebra_parser_bracket extends qtype_algebra_parser_term { } else { $mult = 1; } - if (count($this->_arguments)!= $this->_nargs) { + if (count($this->_arguments) != $this->_nargs) { return 0; } - return $mult*$this->_arguments[0]->evaluate($params); + return $mult * $this->_arguments[0]->evaluate($params); } public function set_negative() { @@ -1437,15 +1432,15 @@ class qtype_algebra_parser { ); // Regular experssion to match an open bracket. - private static $OPENB = '/[\{\(\[]/A'; + private static $openb = '/[\{\(\[]/A'; // Regular experssion to match a close bracket. - private static $CLOSEB = '/[\}\)\]]/A'; + private static $closeb = '/[\}\)\]]/A'; // Regular expression to match a plain float or integer number without exponent. - private static $PLAIN_NUMBER = '(([0-9]+(\.|,)[0-9]*)|([0-9]+)|((\.|,)[0-9]+))'; + private static $plainnumber = '(([0-9]+(\.|,)[0-9]*)|([0-9]+)|((\.|,)[0-9]+))'; // Regular expression to match a float or integer number with an exponent. - private static $EXP_NUMBER = '(([0-9]+(\.|,)[0-9]*)|([0-9]+)|((\.|,)[0-9]+))E([-+]?\d+)'; + private static $expnumber = '(([0-9]+(\.|,)[0-9]*)|([0-9]+)|((\.|,)[0-9]+))E([-+]?\d+)'; // Array to associate close brackets with the correct open bracket type. - private static $BRACKET_MAP = array(')' => '(', ']' => '[', '}' => '{'); + private static $bramap = array(')' => '(', ']' => '[', '}' => '{'); /** * Constructor for the main parser class. @@ -1457,15 +1452,15 @@ class qtype_algebra_parser { */ public function __construct() { $this->_tokens = array ( - array ('/(\^|\*\*)/A', 'qtype_algebra_parser_power' ), - array ('/('.implode('|',self::$functions).')/A', 'qtype_algebra_parser_function' ), - array ('/\//A', 'qtype_algebra_parser_divide' ), - array ('/\*/A', 'qtype_algebra_parser_multiply' ), - array ('/\+/A', 'qtype_algebra_parser_add' ), - array ('/-/A', 'qtype_algebra_parser_subtract' ), - array ('/('.implode('|',self::$specials).')/A', 'qtype_algebra_parser_special' ), - array ('/('.self::$EXP_NUMBER.'|'.self::$PLAIN_NUMBER.')/A', 'qtype_algebra_parser_number' ), - array ('/[A-Za-z][A-Za-z0-9_]*/A', 'qtype_algebra_parser_variable' ) + array ('/(\^|\*\*)/A', 'qtype_algebra_parser_power' ) + , array ('/('.implode('|',self::$functions).')/A', 'qtype_algebra_parser_function' ) + , array ('/\//A', 'qtype_algebra_parser_divide' ) + , array ('/\*/A', 'qtype_algebra_parser_multiply' ) + , array ('/\+/A', 'qtype_algebra_parser_add' ) + , array ('/-/A', 'qtype_algebra_parser_subtract' ) + , array ('/('.implode('|',self::$specials).')/A', 'qtype_algebra_parser_special' ) + , array ('/('.self::$expnumber.'|'.self::$plainnumber.')/A', 'qtype_algebra_parser_number' ) + , array ('/[A-Za-z][A-Za-z0-9_]*/A', 'qtype_algebra_parser_variable' ) ); } @@ -1522,7 +1517,7 @@ class qtype_algebra_parser { $m = array(); // Loop over the expression string moving along it using the offset variable $i while // there are still characters left to parse. - while($i < strlen($text)) { + while ($i < strlen($text)) { // Match any white space at the start of the string and 'remove' it by advancing // the pointer by the length of the string matching the regular expression white // space pattern. @@ -1534,11 +1529,11 @@ class qtype_algebra_parser { } // Since we don't have any white space the first thing we look for (top priority) // are open brackets. - if (preg_match(self::$OPENB, substr($text, $i), $m)) { + if (preg_match(self::$openb, substr($text, $i), $m)) { // Check for a non-operator and if one is found assume implicit multiplication. - if (count($tree)>0 and (is_array($tree[count($tree)-1]) or - (is_object($tree[count($tree)-1]) - and $tree[count($tree)-1]->n_args() == 0))) { + if (count($tree) > 0 and (is_array($tree[count($tree) - 1]) or + (is_object($tree[count($tree) - 1]) + and $tree[count($tree) - 1]->n_args() == 0))) { // Make the implicit assumption explicit by adding an appropriate // multiplication operator. array_push($tree, new qtype_algebra_parser_multiply('*')); @@ -1553,7 +1548,7 @@ class qtype_algebra_parser { continue; } // Now see if we have a close bracket here. - if (preg_match(self::$CLOSEB, substr($text, $i), $m)) { + if (preg_match(self::$closeb, substr($text, $i), $m)) { // First check that the current parse tree has at least one term. if (count($tree) == 0) { throw new Exception(get_string('badclosebracket', 'qtype_algebra')); @@ -1561,13 +1556,12 @@ class qtype_algebra_parser { // Now check that the current tree started with a bracket. if (!is_a($tree[0], 'qtype_algebra_parser_bracket')) { throw new Exception(get_string('mismatchedcloseb', 'qtype_algebra')); - } - // Check that the open and close bracket are of the same type. - else if ($tree[0]->_value != self::$BRACKET_MAP[$m[0]]) { + } else if ($tree[0]->_value != self::$bramap[$m[0]]) { + // Check that the open and close bracket are of the same type. throw new Exception(get_string('mismatchedbracket', 'qtype_algebra', $tree[0]->_value.$m[0])); } // Append the current tree to the tree one level up on the stack. - array_push($stack[count($stack)-1], $tree); + array_push($stack[count($stack) - 1], $tree); // The new tree is the lowest level tree on the stack so we // pop the new tree off the stack. $tree = array_pop($stack); @@ -1578,7 +1572,7 @@ class qtype_algebra_parser { if (!empty($revar) and preg_match($revar, substr($text, $i), $m)) { // Check for a zero argument term or brackets preceding the variable and if there is one then // add the implicit multiplication operation. - if (count($tree)>0 and (is_array($tree[count($tree)-1]) or $tree[count($tree)-1]->n_args() == 0)) { + if (count($tree) > 0 and (is_array($tree[count($tree) - 1]) or $tree[count($tree) - 1]->n_args() == 0)) { array_push($tree, new qtype_algebra_parser_multiply('*')); } // Increment the string index by the length of the variable's name. @@ -1590,9 +1584,7 @@ class qtype_algebra_parser { // Here we have not found any open or close brackets or known variables so we can // parse the string for a normal token. foreach ($this->_tokens as $token) { - //echo 'Looking for token ', $token[1], "\n"; if (preg_match($token[0], substr($text, $i), $m)) { - //echo 'Found a ', $token[1], "!\n"; // Check for a variable and throw an exception if undeclared variables are // not allowed and a list of defined variables was passed. if (!empty($revar) and !$undecvars and $token[1] == 'qtype_algebra_parser_variable') { @@ -1619,8 +1611,6 @@ class qtype_algebra_parser { if (count($stack)>0) { throw new Exception(get_string('mismatchedopenb', 'qtype_algebra')); } - //print_r($tree); - //print_r($stack); return $this->interpret($tree); } @@ -1652,7 +1642,7 @@ class qtype_algebra_parser { } // Next we loop over the tree and look for arrays. These represent // brackets inside our tree and so we need to process them first. - for ($i = 0;$i < count($tree);$i++) { + for ($i = 0; $i < count($tree); $i++) { // Check for a list type if we find one then replace // it with the interpreted term. if (is_array($tree[$i])) { @@ -1662,26 +1652,26 @@ class qtype_algebra_parser { // The next job is to check the subtraction operations to determine whether they are // really subtraction operations or whether they are minus signs for negative numbers. $toremove = array(); - for ($i = 0;$i < count($tree);$i++) { + for ($i = 0; $i < count($tree); $i++) { // Check that this element is an addition or subtraction operator. if (is_a($tree[$i], 'qtype_algebra_parser_subtract') or is_a($tree[$i], 'qtype_algebra_parser_add')) { // Check whether the precedding argument (if there is one) is a number or // a variable. In either case this is a addition/subtraction operation so we continue. - if ($i>0 and (is_a($tree[$i-1], 'qtype_algebra_parser_variable') or - is_a($tree[$i-1], 'qtype_algebra_parser_number') or - is_a($tree[$i-1], 'qtype_algebra_parser_bracket'))) { + if ($i > 0 and (is_a($tree[$i - 1], 'qtype_algebra_parser_variable') or + is_a($tree[$i - 1], 'qtype_algebra_parser_number') or + is_a($tree[$i - 1], 'qtype_algebra_parser_bracket'))) { continue; } // Otherwise we have found a minus sign indicating a positive or negative quantity... else { // Check that we do have a number following otherwise generate an exception... - if ($i == (count($tree)-1) or !method_exists($tree[$i+1], 'set_negative')) { + if ($i == (count($tree) - 1) or !method_exists($tree[$i + 1], 'set_negative')) { throw new Exception(get_string('illegalplusminus', 'qtype_algebra')); } // If we have a subtract operation then we need to make the following number negative. if (is_a($tree[$i], 'qtype_algebra_parser_subtract')) { // Set the number to be negative. - $tree[$i+1]->set_negative(); + $tree[$i + 1]->set_negative(); } // Add the term to the removal list. $toremove[$i] = 1; @@ -1695,23 +1685,23 @@ class qtype_algebra_parser { foreach (self::$priority as $ops) { $i = 0; //echo 'Looking for ', $ops, "\n"; - while($i < count($tree)) { + while ($i < count($tree)) { if (in_array(get_class($tree[$i]), $ops)) { //echo 'Found a ', get_class($tree[$i]), "\n"; if ($tree[$i]->n_args() == 1) { - if (($i+1) < count($tree)) { - $tree[$i]->set_arguments(array_splice($tree, $i+1, 1)); + if (($i + 1) < count($tree)) { + $tree[$i]->set_arguments(array_splice($tree, $i + 1, 1)); $i++; continue; } else { throw new Exception(get_string('missingonearg', 'qtype_algebra', $op)); } } elseif ($tree[$i]->n_args() == 2) { - if ($i > 0 and $i < (count($tree)-1)) { - $tree[$i]->set_arguments(array($tree[$i-1], - $tree[$i+1])); - array_splice($tree, $i+1, 1); - array_splice($tree, $i-1, 1); + if ($i > 0 and $i < (count($tree) - 1)) { + $tree[$i]->set_arguments(array($tree[$i - 1], + $tree[$i + 1])); + array_splice($tree, $i + 1, 1); + array_splice($tree, $i - 1, 1); continue; } else { throw new Exception(get_string('missingtwoargs', 'qtype_algebra', $op)); @@ -1726,7 +1716,7 @@ class qtype_algebra_parser { // in which case we create a null term and return it. if (count($tree) == 0) { return new qtype_algebra_parser_nullterm; - } else if (count($tree)!= 1) { + } else if (count($tree) != 1) { //print_r($tree); throw new Exception(get_string('notopterm', 'qtype_algebra')); } |