class ctools_math_expr in Chaos Tool Suite (ctools) 7
Same name and namespace in other branches
- 6 includes/math-expr.inc \ctools_math_expr
ctools_math_expr Class.
Hierarchy
- class \ctools_math_expr
Expanded class hierarchy of ctools_math_expr
File
- includes/
math-expr.inc, line 68 - =============================================================================.
View source
class ctools_math_expr {
/**
* If TRUE do not call trigger_error on error other wise do.
*
* @var bool
*/
public $suppress_errors = FALSE;
/**
* The last error message reported.
*
* @var string
*/
public $last_error = NULL;
/**
* List of all errors reported.
*
* @var array
*/
public $errors = array();
/**
* Variable and constant values.
*
* @var array
*/
protected $vars;
/**
* User defined functions.
*
* @var array
*/
protected $userfuncs;
/**
* The names of constants, used to make constants read-only.
*
* @var array
*/
protected $constvars;
/**
* Built in simple (one arg) functions.
* Merged into $this->funcs in constructor.
*
* @var array
*/
protected $simplefuncs;
/**
* Definitions of all built-in functions.
*
* @var array
*/
protected $funcs;
/**
* Operators and their precedence.
*
* @var array
*/
protected $ops;
/**
* The set of operators using two arguments.
*
* @var array
*/
protected $binaryops;
/**
* Public constructor.
*/
public function __construct() {
$this->userfuncs = array();
$this->simplefuncs = array(
'sin',
'sinh',
'asin',
'asinh',
'cos',
'cosh',
'acos',
'acosh',
'tan',
'tanh',
'atan',
'atanh',
'exp',
'sqrt',
'abs',
'log',
'ceil',
'floor',
'round',
);
$this->ops = array(
'+' => array(
'precedence' => 0,
),
'-' => array(
'precedence' => 0,
),
'*' => array(
'precedence' => 1,
),
'/' => array(
'precedence' => 1,
),
'^' => array(
'precedence' => 2,
'right' => TRUE,
),
'_' => array(
'precedence' => 1,
),
'==' => array(
'precedence' => -1,
),
'!=' => array(
'precedence' => -1,
),
'>=' => array(
'precedence' => -1,
),
'<=' => array(
'precedence' => -1,
),
'>' => array(
'precedence' => -1,
),
'<' => array(
'precedence' => -1,
),
);
$this->binaryops = array(
'+',
'-',
'*',
'/',
'^',
'==',
'!=',
'<',
'<=',
'>=',
'>',
);
$this->funcs = array(
'ln' => array(
'function' => 'log',
'arguments' => 1,
),
'arcsin' => array(
'function' => 'asin',
'arguments' => 1,
),
'arcsinh' => array(
'function' => 'asinh',
'arguments' => 1,
),
'arccos' => array(
'function' => 'acos',
'arguments' => 1,
),
'arccosh' => array(
'function' => 'acosh',
'arguments' => 1,
),
'arctan' => array(
'function' => 'atan',
'arguments' => 1,
),
'arctanh' => array(
'function' => 'atanh',
'arguments' => 1,
),
'min' => array(
'function' => 'min',
'arguments' => 2,
'max arguments' => 99,
),
'max' => array(
'function' => 'max',
'arguments' => 2,
'max arguments' => 99,
),
'pow' => array(
'function' => 'pow',
'arguments' => 2,
),
'if' => array(
'function' => 'ctools_math_expr_if',
'arguments' => 2,
'max arguments' => 3,
),
'number' => array(
'function' => 'ctools_math_expr_number',
'arguments' => 1,
),
'time' => array(
'function' => 'time',
'arguments' => 0,
),
);
// Allow modules to add custom functions.
$context = array(
'final' => &$this->funcs,
);
drupal_alter('ctools_math_expression_functions', $this->simplefuncs, $context);
// Set up the initial constants and mark them read-only.
$this->vars = array(
'e' => exp(1),
'pi' => pi(),
);
drupal_alter('ctools_math_expression_constants', $this->vars);
$this->constvars = array_keys($this->vars);
// Translate the older, simpler style into the newer, richer style.
foreach ($this->simplefuncs as $function) {
$this->funcs[$function] = array(
'function' => $function,
'arguments' => 1,
);
}
}
/**
* Change the suppress errors flag.
*
* When errors are not suppressed, trigger_error is used to cause a PHP error
* when an evaluation error occurs, as a result of calling trigger(). With
* errors suppressed this doesn't happen.
*
* @param bool $enable
* If FALSE, enable triggering of php errors when expression errors occurs.
* otherwise, suppress triggering the errors.
*
* @return bool
* The new (current) state of the flag.
*
* @see ctools_math_expr::trigger()
*/
public function set_suppress_errors($enable) {
return $this->suppress_errors = (bool) $enable;
}
/**
* Backwards compatible wrapper for evaluate().
*
* @see ctools_math_expr::evaluate()
*/
public function e($expr) {
return $this
->evaluate($expr);
}
/**
* Evaluate the expression.
*
* @param string $expr
* The expression to evaluate.
*
* @return string|bool
* The result of the expression, or FALSE if an error occurred, or TRUE if
* an user-defined function was created.
*/
public function evaluate($expr) {
$this->last_error = NULL;
$expr = trim($expr);
// Strip possible semicolons at the end.
if (substr($expr, -1, 1) == ';') {
$expr = substr($expr, 0, -1);
}
// Is it a variable assignment?
if (preg_match('/^\\s*([a-z]\\w*)\\s*=\\s*(.+)$/', $expr, $matches)) {
// Make sure we're not assigning to a constant.
if (in_array($matches[1], $this->constvars)) {
return $this
->trigger("cannot assign to constant '{$matches[1]}'");
}
// Get the result and make sure it's good:
if (($tmp = $this
->pfx($this
->nfx($matches[2]))) === FALSE) {
return FALSE;
}
// If so, stick it in the variable array...
$this->vars[$matches[1]] = $tmp;
// ...and return the resulting value:
return $this->vars[$matches[1]];
}
elseif (preg_match('/^\\s*([a-z]\\w*)\\s*\\(\\s*([a-z]\\w*(?:\\s*,\\s*[a-z]\\w*)*)\\s*\\)\\s*=\\s*(.+)$/', $expr, $matches)) {
// Get the function name.
$fnn = $matches[1];
// Make sure it isn't built in:
if (isset($this->funcs[$matches[1]])) {
return $this
->trigger("cannot redefine built-in function '{$matches[1]}()'");
}
// Get the arguments.
$args = explode(",", preg_replace("/\\s+/", "", $matches[2]));
// See if it can be converted to postfix.
$stack = $this
->nfx($matches[3]);
if ($stack === FALSE) {
return FALSE;
}
// Freeze the state of the non-argument variables.
for ($i = 0; $i < count($stack); $i++) {
$token = $stack[$i];
if (preg_match('/^[a-z]\\w*$/', $token) and !in_array($token, $args)) {
if (array_key_exists($token, $this->vars)) {
$stack[$i] = $this->vars[$token];
}
else {
return $this
->trigger("undefined variable '{$token}' in function definition");
}
}
}
$this->userfuncs[$fnn] = array(
'args' => $args,
'func' => $stack,
);
return TRUE;
}
else {
// Straight up evaluation.
return trim($this
->pfx($this
->nfx($expr)), '"');
}
}
/**
* Fetch an array of variables used in the expression.
*
* @return array
* Array of name : value pairs, one for each variable defined.
*/
public function vars() {
$output = $this->vars;
// @todo: Is this supposed to remove all constants? we should remove all
// those in $this->constvars!
unset($output['pi']);
unset($output['e']);
return $output;
}
/**
* Fetch all user defined functions in the expression.
*
* @return array
* Array of name : string pairs, one for each function defined. The string
* will be of the form fname(arg1,arg2). The function body is not returned.
*/
public function funcs() {
$output = array();
foreach ($this->userfuncs as $fnn => $dat) {
$output[] = $fnn . '(' . implode(',', $dat['args']) . ')';
}
return $output;
}
/**
* Convert infix to postfix notation.
*
* @param string $expr
* The expression to convert.
*
* @return array|bool
* The expression as an ordered list of postfix action tokens.
*/
private function nfx($expr) {
$index = 0;
$stack = new ctools_math_expr_stack();
// Postfix form of expression, to be passed to pfx().
$output = array();
// @todo: Because the expr can contain string operands, using strtolower here is a bug.
$expr = trim(strtolower($expr));
// We use this in syntax-checking the expression and determining when
// '-' is a negation.
$expecting_op = FALSE;
while (TRUE) {
$op = substr($expr, $index, 1);
// Get the first character at the current index, and if the second
// character is an =, add it to our op as well (accounts for <=).
if (substr($expr, $index + 1, 1) === '=') {
$op = substr($expr, $index, 2);
$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), $match);
// Is it a negation instead of a minus?
if ($op === '-' and !$expecting_op) {
// Put a negation on the stack.
$stack
->push('_');
$index++;
}
elseif ($op == '_') {
return $this
->trigger("illegal character '_'");
}
elseif ((isset($this->ops[$op]) || $ex) && $expecting_op) {
// Are we expecting an operator but have a num, var, func, or
// open-paren?
if ($ex) {
$op = '*';
// It's an implicit multiplication.
$index--;
}
// Heart of the algorithm:
while ($stack
->count() > 0 && ($o2 = $stack
->last()) && isset($this->ops[$o2]) && (!empty($this->ops[$op]['right']) ? $this->ops[$op]['precedence'] < $this->ops[$o2]['precedence'] : $this->ops[$op]['precedence'] <= $this->ops[$o2]['precedence'])) {
// Pop stuff off the stack into the output.
$output[] = $stack
->pop();
}
// Many thanks: http://en.wikipedia.org/wiki/Reverse_Polish_notation#The_algorithm_in_detail
// finally put OUR operator onto the stack.
$stack
->push($op);
$index++;
$expecting_op = FALSE;
}
elseif ($op === ')') {
// Pop off the stack back to the last '('.
while (($o2 = $stack
->pop()) !== '(') {
if (is_null($o2)) {
return $this
->trigger("unexpected ')'");
}
else {
$output[] = $o2;
}
}
// Did we just close a function?
if (preg_match("/^([a-z]\\w*)\\(\$/", $stack
->last(2), $matches)) {
// Get the function name.
$fnn = $matches[1];
// See how many arguments there were (cleverly stored on the stack,
// thank you).
$arg_count = $stack
->pop();
// Pop the function and push onto the output.
$output[] = $stack
->pop();
// Check the argument count:
if (isset($this->funcs[$fnn])) {
$fdef = $this->funcs[$fnn];
$max_arguments = isset($fdef['max arguments']) ? $fdef['max arguments'] : $fdef['arguments'];
if ($arg_count > $max_arguments) {
return $this
->trigger("too many arguments ({$arg_count} given, {$max_arguments} expected)");
}
}
elseif (array_key_exists($fnn, $this->userfuncs)) {
$fdef = $this->userfuncs[$fnn];
if ($arg_count !== count($fdef['args'])) {
return $this
->trigger("wrong number of arguments ({$arg_count} given, " . count($fdef['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 === ',' && $expecting_op) {
$index++;
$expecting_op = FALSE;
}
elseif ($op === '(' && !$expecting_op) {
$stack
->push('(');
$index++;
}
elseif ($ex && !$expecting_op) {
// Make sure there was a function.
if (preg_match("/^([a-z]\\w*)\\(\$/", $stack
->last(3), $matches)) {
// Pop the argument expression stuff and push onto the output:
while (($o2 = $stack
->pop()) !== '(') {
// Oops, never had a '('.
if (is_null($o2)) {
return $this
->trigger("unexpected argument in {$expr} {$o2}");
}
else {
$output[] = $o2;
}
}
// Increment the argument count.
$stack
->push($stack
->pop() + 1);
// Put the ( back on, we'll need to pop back to it again.
$stack
->push('(');
}
// Do we now have a function/variable/number?
$expecting_op = TRUE;
$val = $match[1];
if (preg_match("/^([a-z]\\w*)\\(\$/", $val, $matches)) {
// May be func, or variable w/ implicit multiplication against
// parentheses...
if (isset($this->funcs[$matches[1]]) or array_key_exists($matches[1], $this->userfuncs)) {
$stack
->push($val);
$stack
->push(0);
$stack
->push('(');
$expecting_op = FALSE;
}
else {
$val = $matches[1];
$output[] = $val;
}
}
else {
$output[] = $val;
}
$index += strlen($val);
}
elseif ($op === ')') {
// Miscellaneous error checking.
return $this
->trigger("unexpected ')'");
}
elseif (isset($this->ops[$op]) and !$expecting_op) {
return $this
->trigger("unexpected operator '{$op}'");
}
elseif ($op === '"') {
// Fetch a quoted string.
$string = substr($expr, $index);
if (preg_match('/"[^"\\\\]*(?:\\\\.[^"\\\\]*)*"/s', $string, $matches)) {
$string = $matches[0];
// Trim the quotes off:
$output[] = $string;
$index += strlen($string);
$expecting_op = TRUE;
}
else {
return $this
->trigger('open quote without close quote.');
}
}
else {
// I don't even want to know what you did to get here.
return $this
->trigger("an unexpected error occurred at {$op}");
}
if ($index === strlen($expr)) {
if (isset($this->ops[$op])) {
// Did we end with an operator? bad.
return $this
->trigger("operator '{$op}' lacks operand");
}
else {
break;
}
}
// Step the index past whitespace (pretty much turns whitespace into
// implicit multiplication if no operator is there).
while (substr($expr, $index, 1) === ' ') {
$index++;
}
}
// Pop everything off the stack and push onto output:
while (!is_null($op = $stack
->pop())) {
// If there are (s on the stack, ()s were unbalanced.
if ($op === '(') {
return $this
->trigger("expecting ')'");
}
$output[] = $op;
}
return $output;
}
/**
* Evaluate a prefix-operator stack expression.
*
* @param array $tokens
* The array of token values to evaluate. A token is a string value
* representing either an operation to perform, a variable, or a value.
* Literal values are checked using is_numeric(), or a value that starts
* with a double-quote; functions and variables by existence in the
* appropriate tables.
* If FALSE is passed in the function terminates immediately, returning
* FALSE.
* @param array $vars
* Additional variable values to use when evaluating the expression. These
* variables do not override internal variables with the same name.
*
* @return bool|mixed
* The expression's value, otherwise FALSE is returned if there is an error
* detected unless php error handling intervenes: see suppress_error.
*/
public function pfx(array $tokens, array $vars = array()) {
if ($tokens == FALSE) {
return FALSE;
}
$stack = new ctools_math_expr_stack();
foreach ($tokens as $token) {
// If the token is a binary operator, pop two values off the stack, do
// the operation, and push the result back on again.
if (in_array($token, $this->binaryops)) {
if (is_null($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;
case '==':
$stack
->push((int) ($op1 == $op2));
break;
case '!=':
$stack
->push((int) ($op1 != $op2));
break;
case '<=':
$stack
->push((int) ($op1 <= $op2));
break;
case '<':
$stack
->push((int) ($op1 < $op2));
break;
case '>=':
$stack
->push((int) ($op1 >= $op2));
break;
case '>':
$stack
->push((int) ($op1 > $op2));
break;
}
}
elseif ($token === "_") {
$stack
->push(-1 * $stack
->pop());
}
elseif (preg_match("/^([a-z]\\w*)\\(\$/", $token, $matches)) {
$fnn = $matches[1];
// Check for a built-in function.
if (isset($this->funcs[$fnn])) {
$args = array();
// Collect all required args from the stack.
for ($i = 0; $i < $this->funcs[$fnn]['arguments']; $i++) {
if (is_null($op1 = $stack
->pop())) {
return $this
->trigger("function {$fnn} missing argument {$i}");
}
$args[] = $op1;
}
// If func allows additional args, collect them too, stopping on a
// NULL arg.
if (!empty($this->funcs[$fnn]['max arguments'])) {
for (; $i < $this->funcs[$fnn]['max arguments']; $i++) {
$arg = $stack
->pop();
if (!isset($arg)) {
break;
}
$args[] = $arg;
}
}
$stack
->push(call_user_func_array($this->funcs[$fnn]['function'], array_reverse($args)));
}
elseif (isset($fnn, $this->userfuncs)) {
$args = array();
for ($i = count($this->userfuncs[$fnn]['args']) - 1; $i >= 0; $i--) {
$value = $stack
->pop();
$args[$this->userfuncs[$fnn]['args'][$i]] = $value;
if (is_null($value)) {
return $this
->trigger('internal error');
}
}
// yay... recursion!!!!
$stack
->push($this
->pfx($this->userfuncs[$fnn]['func'], $args));
}
}
else {
if (is_numeric($token) || $token[0] == '"') {
$stack
->push($token);
}
elseif (array_key_exists($token, $this->vars)) {
$stack
->push($this->vars[$token]);
}
elseif (array_key_exists($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();
}
/**
* Trigger an error, but nicely, if need be.
*
* @param string $msg
* Message to add to trigger error.
*
* @return bool
* Can trigger error, then returns FALSE.
*/
protected function trigger($msg) {
$this->errors[] = $msg;
$this->last_error = $msg;
if (!$this->suppress_errors) {
trigger_error($msg, E_USER_WARNING);
}
return FALSE;
}
}Members
Name |
Modifiers | Type | Description | Overrides |
|---|---|---|---|---|
|
ctools_math_expr:: |
protected | property | The set of operators using two arguments. | |
|
ctools_math_expr:: |
protected | property | The names of constants, used to make constants read-only. | |
|
ctools_math_expr:: |
public | property | List of all errors reported. | |
|
ctools_math_expr:: |
protected | property | Definitions of all built-in functions. | |
|
ctools_math_expr:: |
public | property | The last error message reported. | |
|
ctools_math_expr:: |
protected | property | Operators and their precedence. | |
|
ctools_math_expr:: |
protected | property | Built in simple (one arg) functions. Merged into $this->funcs in constructor. | |
|
ctools_math_expr:: |
public | property | If TRUE do not call trigger_error on error other wise do. | |
|
ctools_math_expr:: |
protected | property | User defined functions. | |
|
ctools_math_expr:: |
protected | property | Variable and constant values. | |
|
ctools_math_expr:: |
public | function | Backwards compatible wrapper for evaluate(). | |
|
ctools_math_expr:: |
public | function | Evaluate the expression. | |
|
ctools_math_expr:: |
public | function | Fetch all user defined functions in the expression. | |
|
ctools_math_expr:: |
private | function | Convert infix to postfix notation. | |
|
ctools_math_expr:: |
public | function | Evaluate a prefix-operator stack expression. | |
|
ctools_math_expr:: |
public | function | Change the suppress errors flag. | |
|
ctools_math_expr:: |
protected | function | Trigger an error, but nicely, if need be. | |
|
ctools_math_expr:: |
public | function | Fetch an array of variables used in the expression. | |
|
ctools_math_expr:: |
public | function | Public constructor. |