function pfx($tokens, $vars = array())
{
if ($tokens == false) {
return false;
}
$stack = new EvalMathStack();
foreach ($tokens as $token) {
// nice and easy
// if the token is a binary operator, pop two values off the stack, do the operation, and push the result back on
if (in_array($token, array('+', '-', '*', '/', '^'))) {
if (is_null($op2 = $stack->pop())) {
return $this->trigger("internal error");
}
if (is_null($op1 = $stack->pop())) {
return $this->trigger("internal error");
}
switch ($token) {
case '+':
$stack->push($op1 + $op2);
break;
case '-':
$stack->push($op1 - $op2);
break;
case '*':
$stack->push($op1 * $op2);
break;
case '/':
if ($op2 == 0) {
return $this->trigger("division by zero");
}
$stack->push($op1 / $op2);
break;
case '^':
$stack->push(pow($op1, $op2));
break;
}
// if the token is a unary operator, pop one value off the stack, do the operation, and push it back on
} elseif ($token == "_") {
$stack->push(-1 * $stack->pop());
// if the token is a function, pop arguments off the stack, hand them to the function, and push the result back on
} elseif (preg_match("/^([a-z]\\w*)\\(\$/", $token, $matches)) {
// it's a function!
$fnn = $matches[1];
if (in_array($fnn, $this->fb)) {
// built-in function:
if (is_null($op1 = $stack->pop())) {
return $this->trigger("internal error");
}
$fnn = preg_replace("/^arc/", "a", $fnn);
// for the 'arc' trig synonyms
if ($fnn == 'ln') {
$fnn = 'log';
}
eval('$stack->push(' . $fnn . '($op1));');
// perfectly safe eval()
} elseif (array_key_exists($fnn, $this->f)) {
// user function
// get args
$args = array();
for ($i = count($this->f[$fnn]['args']) - 1; $i >= 0; $i--) {
if (is_null($args[$this->f[$fnn]['args'][$i]] = $stack->pop())) {
return $this->trigger("internal error");
}
}
$stack->push($this->pfx($this->f[$fnn]['func'], $args));
// yay... recursion!!!!
}
// if the token is a number or variable, push it on the stack
} else {
if (is_numeric($token)) {
$stack->push($token);
} elseif (array_key_exists($token, $this->v)) {
$stack->push($this->v[$token]);
} elseif (array_key_exists($token, $vars)) {
$stack->push($vars[$token]);
} else {
return $this->trigger("undefined variable '{$token}'");
}
}
}
// when we're out of tokens, the stack should have a single element, the final result
if ($stack->count != 1) {
return $this->trigger("internal error");
}
return $stack->pop();
}
function pfx($tokens, $vars = array())
{
if ($tokens == false) {
return false;
}
$stack = new EvalMathStack();
foreach ($tokens as $token) {
// nice and easy
// if the token is a function, pop arguments off the stack, hand them to the function, and push the result back on
if (is_array($token)) {
// it's a function!
$fnn = $token['fnn'];
$count = $token['argcount'];
if (in_array($fnn, $this->fb)) {
// built-in function:
if (is_null($op1 = $stack->pop())) {
return $this->trigger("internal error");
}
$fnn = preg_replace("/^arc/", "a", $fnn);
// for the 'arc' trig synonyms
if ($fnn == 'ln') {
$fnn = 'log';
}
eval('$stack->push(' . $fnn . '($op1));');
// perfectly safe eval()
} elseif (array_key_exists($fnn, $this->fc)) {
// calc emulation function
// get args
$args = array();
for ($i = $count - 1; $i >= 0; $i--) {
if (is_null($args[] = $stack->pop())) {
return $this->trigger("internal error");
}
}
$res = call_user_func(array('EvalMathCalcEmul', $fnn), $args);
if ($res === FALSE) {
return $this->trigger("internal error");
}
$stack->push($res);
} elseif (array_key_exists($fnn, $this->f)) {
// user function
// get args
$args = array();
for ($i = count($this->f[$fnn]['args']) - 1; $i >= 0; $i--) {
if (is_null($args[$this->f[$fnn]['args'][$i]] = $stack->pop())) {
return $this->trigger("internal error");
}
}
$stack->push($this->pfx($this->f[$fnn]['func'], $args));
// yay... recursion!!!!
}
// if the token is a binary operator, pop two values off the stack, do the operation, and push the result back on
} elseif (in_array($token, array('+', '-', '*', '/', '^'), true)) {
if (is_null($op2 = $stack->pop())) {
return $this->trigger("internal error");
}
if (is_null($op1 = $stack->pop())) {
return $this->trigger("internal error");
}
switch ($token) {
case '+':
$this->index += 1;
$stack->push($this->index);
$this->data[$this->index] = array_merge($this->data[$op1], $this->data[$op2]);
break;
case '-':
$this->index += 1;
$stack->push($this->index);
$this->data[$this->index] = array_diff($this->data[$op1], $this->data[$op2]);
break;
case '*':
$this->index += 1;
$stack->push($this->index);
$this->data[$this->index] = array_intersect($this->data[$op1], $this->data[$op2]);
break;
}
// if the token is a unary operator, pop one value off the stack, do the operation, and push it back on
} elseif ($token == "_") {
$stack->push(-1 * $stack->pop());
// if the token is a number or variable, push it on the stack
} else {
if (is_numeric($token)) {
$stack->push($token);
} elseif (array_key_exists($token, $this->v)) {
$stack->push($this->v[$token]);
} elseif (array_key_exists($token, $vars)) {
$stack->push($vars[$token]);
} else {
return $this->trigger("undefined variable '{$token}'");
}
}
}
// when we're out of tokens, the stack should have a single element, the final result
if ($stack->count != 1) {
return $this->trigger("internal error");
}
$last = $stack->pop();
if (isset($this->data[$last])) {
return $this->data[$last];
} else {
return false;
}
}
function pfx($tokens, $vars = array())
{
if ($tokens == false) {
return false;
}
$stack = new EvalMathStack();
foreach ($tokens as $token) {
// nice and easy
// if the token is a function, pop arguments off the stack, hand them to the function, and push the result back on
if (is_array($token)) {
// it's a function!
$fnn = $token['fnn'];
$count = $token['argcount'];
if (in_array($fnn, $this->fb)) {
// built-in function:
if (is_null($op1 = $stack->pop())) {
return $this->trigger($this->get_string('internalerror', 'mathslib'));
}
$fnn = preg_replace("/^arc/", "a", $fnn);
// for the 'arc' trig synonyms
if ($fnn == 'ln') {
$fnn = 'log';
}
eval('$stack->push(' . $fnn . '($op1));');
// perfectly safe eval()
} elseif (array_key_exists($fnn, $this->fc)) {
// calc emulation function
// get args
$args = array();
for ($i = $count - 1; $i >= 0; $i--) {
if (is_null($args[] = $stack->pop())) {
return $this->trigger($this->get_string('internalerror', 'mathslib'));
}
}
$res = call_user_func_array(array('EvalMathFuncs', $fnn), array_reverse($args));
if ($res === FALSE) {
return $this->trigger($this->get_string('internalerror', 'mathslib'));
}
$stack->push($res);
} elseif (array_key_exists($fnn, $this->f)) {
// user function
// get args
$args = array();
for ($i = count($this->f[$fnn]['args']) - 1; $i >= 0; $i--) {
if (is_null($args[$this->f[$fnn]['args'][$i]] = $stack->pop())) {
return $this->trigger($this->get_string('internalerror', 'mathslib'));
}
}
$stack->push($this->pfx($this->f[$fnn]['func'], $args));
// yay... recursion!!!!
}
// if the token is a binary operator, pop two values off the stack, do the operation, and push the result back on
} elseif (in_array($token, array('+', '-', '*', '/', '^'), true)) {
if (is_null($op2 = $stack->pop())) {
return $this->trigger($this->get_string('internalerror', 'mathslib'));
}
if (is_null($op1 = $stack->pop())) {
return $this->trigger($this->get_string('internalerror', 'mathslib'));
}
switch ($token) {
case '+':
$stack->push($op1 + $op2);
break;
case '-':
$stack->push($op1 - $op2);
break;
case '*':
$stack->push($op1 * $op2);
break;
case '/':
if ($op2 == 0) {
return $this->trigger($this->get_string('divisionbyzero', 'mathslib'));
}
$stack->push($op1 / $op2);
break;
case '^':
$stack->push(pow($op1, $op2));
break;
}
// if the token is a unary operator, pop one value off the stack, do the operation, and push it back on
} elseif ($token == "_") {
$stack->push(-1 * $stack->pop());
// if the token is a number or variable, push it on the stack
} else {
if (is_numeric($token)) {
$stack->push($token);
} elseif (array_key_exists($token, $this->v)) {
$stack->push($this->v[$token]);
} elseif (array_key_exists($token, $vars)) {
$stack->push($vars[$token]);
} else {
// If variable is undefined, create it with value 0
$this->v[$token] = 0;
$stack->push($this->v[$token]);
//return $this->trigger($this->get_string('undefinedvariable', 'mathslib', $token));
}
}
}
// when we're out of tokens, the stack should have a single element, the final result
if ($stack->count != 1) {
return $this->trigger($this->get_string('internalerror', 'mathslib'));
}
return $stack->pop();
}
function pfx($tokens, $vars = array())
{
if ($tokens == false) {
return false;
}
$stack = new EvalMathStack();
foreach ($tokens as $token) {
if (in_array($token, array('+', '-', '*', '/', '^'))) {
if (is_null($op2 = $stack->pop())) {
return $this->trigger("internal error");
}
if (is_null($op1 = $stack->pop())) {
return $this->trigger("internal error");
}
switch ($token) {
case '+':
$stack->push($op1 + $op2);
break;
case '-':
$stack->push($op1 - $op2);
break;
case '*':
$stack->push($op1 * $op2);
break;
case '/':
if ($op2 == 0) {
return $this->trigger("division by zero");
}
$stack->push($op1 / $op2);
break;
case '^':
$stack->push(pow($op1, $op2));
break;
}
} elseif ($token == "_") {
$stack->push(-1 * $stack->pop());
} elseif (preg_match("/^([a-z]\\w*)\\(\$/", $token, $matches)) {
$fnn = $matches[1];
if (in_array($fnn, $this->fb)) {
if (is_null($op1 = $stack->pop())) {
return $this->trigger("internal error");
}
$fnn = preg_replace("/^arc/", "a", $fnn);
if ($fnn == 'ln') {
$fnn = 'log';
}
eval('$stack->push(' . $fnn . '($op1));');
} elseif (array_key_exists($fnn, $this->f)) {
$args = array();
for ($i = count($this->f[$fnn]['args']) - 1; $i >= 0; $i--) {
if (is_null($args[$this->f[$fnn]['args'][$i]] = $stack->pop())) {
return $this->trigger("internal error");
}
}
$stack->push($this->pfx($this->f[$fnn]['func'], $args));
}
} else {
if (is_numeric($token)) {
$stack->push($token);
} elseif (array_key_exists($token, $this->v)) {
$stack->push($this->v[$token]);
} elseif (array_key_exists($token, $vars)) {
$stack->push($vars[$token]);
} else {
return $this->trigger("undefined variable '{$token}'");
}
}
}
if ($stack->count != 1) {
return $this->trigger("internal error");
}
return $stack->pop();
}
function nfx($expr)
{
$index = 0;
$stack = new EvalMathStack();
$output = array();
// postfix form of expression, to be passed to pfx()
$expr = trim(strtolower($expr));
$ops = array('+', '-', '*', '/', '^', '_');
$ops_r = array('+' => 0, '-' => 0, '*' => 0, '/' => 0, '^' => 1);
// right-associative operator?
$ops_p = array('+' => 0, '-' => 0, '*' => 1, '/' => 1, '_' => 1, '^' => 2);
// operator precedence
$expecting_op = false;
// we use this in syntax-checking the expression
// and determining when a - is a negation
if (preg_match("/[^\\w\\s+*^\\/()\\.,-]/", $expr, $matches)) {
// make sure the characters are all good
return $this->trigger("illegal character '{$matches[0]}'");
}
while (1) {
// 1 Infinite Loop ;)
$op = substr($expr, $index, 1);
// get the first character at the current index
// find out if we're currently at the beginning of a number/variable/function/parenthesis/operand
$ex = preg_match('/^([a-z]\\w*\\(?|\\d+(?:\\.\\d*)?|\\.\\d+|\\()/', substr($expr, $index), $match);
//===============
if ($op == '-' and !$expecting_op) {
// is it a negation instead of a minus?
$stack->push('_');
// put a negation on the stack
$index++;
} elseif ($op == '_') {
// we have to explicitly deny this, because it's legal on the stack
return $this->trigger("illegal character '_'");
// but not in the input expression
//===============
} elseif ((in_array($op, $ops) or $ex) and $expecting_op) {
// are we putting an operator on the stack?
if ($ex) {
// are we expecting an operator but have a number/variable/function/opening parethesis?
$op = '*';
$index--;
// it's an implicit multiplication
}
// heart of the algorithm:
while ($stack->count > 0 and $o2 = $stack->last() and in_array($o2, $ops) and $ops_r[$op] ? $ops_p[$op] < $ops_p[$o2] : $ops_p[$op] <= $ops_p[$o2]) {
$output[] = $stack->pop();
// pop stuff off the stack into the output
}
// many thanks: http://en.wikipedia.org/wiki/Reverse_Polish_notation#The_algorithm_in_detail
$stack->push($op);
// finally put OUR operator onto the stack
$index++;
$expecting_op = false;
//===============
} elseif ($op == ')' and $expecting_op) {
// ready to close a parenthesis?
while (($o2 = $stack->pop()) != '(') {
// pop off the stack back to the last (
if (is_null($o2)) {
return $this->trigger("unexpected ')'");
} else {
$output[] = $o2;
}
}
if (preg_match("/^([a-z]\\w*)\\(\$/", $stack->last(2), $matches)) {
// did we just close a function?
$fnn = $matches[1];
// get the function name
$arg_count = $stack->pop();
// see how many arguments there were (cleverly stored on the stack, thank you)
$output[] = $stack->pop();
// pop the function and push onto the output
if (in_array($fnn, $this->fb)) {
// check the argument count
if ($arg_count > 1) {
return $this->trigger("too many arguments ({$arg_count} given, 1 expected)");
}
} elseif (array_key_exists($fnn, $this->f)) {
if ($arg_count != count($this->f[$fnn]['args'])) {
return $this->trigger("wrong number of arguments ({$arg_count} given, " . count($this->f[$fnn]['args']) . " expected)");
}
} else {
// did we somehow push a non-function on the stack? this should never happen
return $this->trigger("internal error");
}
}
$index++;
//===============
} elseif ($op == ',' and $expecting_op) {
// did we just finish a function argument?
while (($o2 = $stack->pop()) != '(') {
if (is_null($o2)) {
return $this->trigger("unexpected ','");
} else {
$output[] = $o2;
}
// pop the argument expression stuff and push onto the output
}
// make sure there was a function
if (!preg_match("/^([a-z]\\w*)\\(\$/", $stack->last(2), $matches)) {
return $this->trigger("unexpected ','");
}
$stack->push($stack->pop() + 1);
// increment the argument count
$stack->push('(');
// put the ( back on, we'll need to pop back to it again
$index++;
$expecting_op = false;
//===============
} elseif ($op == '(' and !$expecting_op) {
$stack->push('(');
// that was easy
$index++;
$allow_neg = true;
//===============
} elseif ($ex and !$expecting_op) {
// do we now have a function/variable/number?
$expecting_op = true;
$val = $match[1];
if (preg_match("/^([a-z]\\w*)\\(\$/", $val, $matches)) {
// may be func, or variable w/ implicit multiplication against parentheses...
if (in_array($matches[1], $this->fb) or array_key_exists($matches[1], $this->f)) {
// it's a func
$stack->push($val);
$stack->push(1);
$stack->push('(');
$expecting_op = false;
} else {
// it's a var w/ implicit multiplication
$val = $matches[1];
$output[] = $val;
}
} else {
// it's a plain old var or num
$output[] = $val;
}
$index += strlen($val);
//===============
} elseif ($op == ')') {
// miscellaneous error checking
return $this->trigger("unexpected ')'");
} elseif (in_array($op, $ops) and !$expecting_op) {
return $this->trigger("unexpected operator '{$op}'");
} else {
// I don't even want to know what you did to get here
return $this->trigger("an unexpected error occured");
}
if ($index == strlen($expr)) {
if (in_array($op, $ops)) {
// did we end with an operator? bad.
return $this->trigger("operator '{$op}' lacks operand");
} else {
break;
}
}
while (substr($expr, $index, 1) == ' ') {
// step the index past whitespace (pretty much turns whitespace
$index++;
// into implicit multiplication if no operator is there)
}
}
while (!is_null($op = $stack->pop())) {
// pop everything off the stack and push onto output
if ($op == '(') {
return $this->trigger("expecting ')'");
}
// if there are (s on the stack, ()s were unbalanced
$output[] = $op;
}
return $output;
}
/**
* Evaluate postfix notation
*
* @param array $tokens
* The list of tokens that make up the expression.
* @param array $vars
* The list of variables set previously.
*
* @return number
* The final result of the evaluation.
*/
private function postfixEvaluate($tokens, $vars = array())
{
if ($tokens == FALSE) {
return FALSE;
}
$stack = new EvalMathStack();
foreach ($tokens as $token) {
if (in_array($token, array('+', '-', '*', '/', '^'))) {
if (is_NULL($op2 = $stack->pop())) {
return $this->trigger(t('internal error'));
}
if (is_NULL($op1 = $stack->pop())) {
return $this->trigger(t('internal error'));
}
switch ($token) {
case '+':
$stack->push($op1 + $op2);
break;
case '-':
$stack->push($op1 - $op2);
break;
case '*':
$stack->push($op1 * $op2);
break;
case '/':
if ($op2 == 0) {
return $this->trigger(t('division by zero'));
}
$stack->push($op1 / $op2);
break;
case '^':
$stack->push(pow($op1, $op2));
break;
}
} elseif ($token == "_") {
$stack->push(-1 * $stack->pop());
} elseif (preg_match("/^([a-z]\\w*)\\(\$/", $token, $matches)) {
$fnn = $matches[1];
if (array_key_exists($fnn, $this->funcAliases)) {
$fnn = $this->funcAliases[$fnn];
}
if (array_key_exists($fnn, $this->funcBuildIn)) {
$argCount = $this->funcBuildIn[$fnn];
$args = array();
for ($i = $argCount; $i > 0; $i--) {
$arg = $stack->pop();
if (is_NULL($arg)) {
return $this->trigger(t('internal error: argument is null'));
}
$args[] = $arg;
$args = array_reverse($args);
}
$stack->push(call_user_func_array($fnn, $args));
} elseif (array_key_exists($fnn, $this->funcUser)) {
$args = array();
for ($i = count($this->funcUser[$fnn]['args']) - 1; $i >= 0; $i--) {
if (is_NULL($args[$this->funcUser[$fnn]['args'][$i]] = $stack->pop())) {
return $this->trigger(t('internal error: argument is null'));
}
}
$stack->push($this->postfixEvaluate($this->funcUser[$fnn]['func'], $args));
}
} else {
if (is_numeric($token)) {
$stack->push($token);
} elseif (array_key_exists($token, $this->variables)) {
$stack->push($this->variables[$token]);
} elseif (array_key_exists($token, $vars)) {
$stack->push($vars[$token]);
} else {
return $this->trigger(t('undefined variable "%token"', array('%token' => $token)));
}
}
}
if ($stack->getCount() != 1) {
return $this->trigger(t('internal error, stack not empty'));
}
return $stack->pop();
}
