Add a Lexer/Parser for mathematical expressions. (Input Processor + Separate Action & Condition)

src/Math/Calculator.php

@@ -0,0 +1,127 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\rules\Math\Calculator.
+ */
+
+namespace Drupal\rules\Math;
+
+use Drupal\rules\Math\Exception\IncorrectExpressionException;
+use Drupal\rules\Math\Exception\UnknownVariableException;
+use Drupal\rules\Math\Token\FunctionToken;
+use Drupal\rules\Math\Token\NumberToken;
+use Drupal\rules\Math\Token\OperatorTokenInterface;
+use Drupal\rules\Math\Token\VariableToken;
+
+/**
+ * Parser for mathematical expressions.
+ */
+class Calculator {
+
+  /**
+   * Static cache of token streams in reverse polish (postfix) notation.
+   *
+   * @var array
+   */
+  protected $tokenCache = [];
+
+  /**
+   * Constructs a new Calculator object.
+   */
+  public function __construct() {
+    $this->lexer = new Lexer();
+
+    $this->lexer
+      ->addOperator('plus', '\+', 'Drupal\rules\Math\Token\PlusToken')
+      ->addOperator('minus', '\-', 'Drupal\rules\Math\Token\MinusToken')
+      ->addOperator('multiply', '\*', 'Drupal\rules\Math\Token\MultiplyToken')
+      ->addOperator('division', '\/', 'Drupal\rules\Math\Token\DivisionToken')
+      ->addOperator('modulus', '\%', 'Drupal\rules\Math\Token\ModulusToken')
+      ->addOperator('power', '\^', 'Drupal\rules\Math\Token\PowerToken');
+
+    $this->lexer
+      ->addFunction('abs', 'abs', 1)
+      ->addFunction('acos', 'acos', 1)
+      ->addFunction('acosh', 'acosh', 1)
+      ->addFunction('asin', 'asin', 1)
+      ->addFunction('asinh', 'asinh', 1)
+      ->addFunction('atan2', 'atan2', 2)
+      ->addFunction('atan', 'atan', 1)
+      ->addFunction('atanh', 'atanh', 1)
+      ->addFunction('ceil', 'ceil', 1)
+      ->addFunction('cos', 'cos', 1)
+      ->addFunction('cosh', 'cosh', 1)
+      ->addFunction('deg2rad', 'deg2rad', 1)
+      ->addFunction('exp', 'exp', 1)
+      ->addFunction('floor', 'floor', 1)
+      ->addFunction('hypot', 'hypot', 2)
+      ->addFunction('log10', 'log10', 1)
+      ->addFunction('log', 'log', 2)
+      ->addFunction('max', 'max', 2)
+      ->addFunction('min', 'min', 2)
+      ->addFunction('pow', 'pow', 2)
+      ->addFunction('rad2deg', 'rad2deg', 1)
+      ->addFunction('rand', 'rand', 2)
+      ->addFunction('round', 'round', 1)
+      ->addFunction('sin', 'sin', 1)
+      ->addFunction('sinh', 'sinh', 1)
+      ->addFunction('sqrt', 'sqrt', 1)
+      ->addFunction('tan', 'tan', 1)
+      ->addFunction('tanh', 'tanh', 1);
+
+    $this->lexer
+      ->addConstant('pi', pi())
+      ->addConstant('e', exp(1));
+  }
+
+  /**
+   * Calculates the result of a mathematical expression.
+   *
+   * @param string $expression
+   *   The mathematical expression.
+   * @param array $variables
+   *   A list of numerical values keyed by their variable names.
+   *
+   * @return mixed
+   *   The result of the mathematical expression.
+   *
+   * @throws \Drupal\rules\Math\Exception\IncorrectExpressionException
+   * @throws \Drupal\rules\Math\Exception\IncorrectParenthesisException
+   */
+  public function calculate($expression, $variables) {
+    $hash = md5($expression);
+    if (isset($this->tokenCache[$hash])) {
+      return $this->tokenCache[$hash];
+    }
+
+    $stream = $this->lexer->tokenize($expression);
+    $tokens = $this->lexer->postfix($stream);
+    $this->tokenCache[$hash] = $tokens;
+
+    $stack = [];
+    foreach ($tokens as $token) {
+      if ($token instanceof NumberToken) {
+        array_push($stack, $token);
+      }
+      elseif ($token instanceof VariableToken) {
+        $identifier = $token->getValue();
+        if (!isset($variables[$identifier])) {
+          throw new UnknownVariableException($token->getOffset(), $identifier);
+        }
+        array_push($stack, new NumberToken($token->getOffset(), $variables[$identifier]));
+      }
+      elseif ($token instanceof OperatorTokenInterface || $token instanceof FunctionToken) {
+        array_push($stack, $token->execute($stack));
+      }
+    }
+
+    $result = array_pop($stack);
+    if (!empty($stack)) {
+      throw new IncorrectExpressionException();
+    }
+
+    return $result->getValue();
+  }
+
+}

src/Math/Exception/IncorrectExpressionException.php

@@ -0,0 +1,14 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\rules\Math\Exception\IncorrectExpressionException.
+ */
+
+namespace Drupal\rules\Math\Exception;
+
+use Drupal\rules\Exception\RulesException;
+
+class IncorrectExpressionException extends RulesException {
+
+}

src/Math/Exception/IncorrectParenthesisException.php

@@ -0,0 +1,14 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\rules\Math\Exception\IncorrectParenthesisException.
+ */
+
+namespace Drupal\rules\Math\Exception;
+
+use Drupal\rules\Exception\RulesException;
+
+class IncorrectParenthesisException extends RulesException {
+
+}

src/Math/Exception/UnknownConstantException.php

@@ -0,0 +1,14 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\rules\Math\Exception\UnknownConstantException.
+ */
+
+namespace Drupal\rules\Math\Exception;
+
+use Drupal\rules\Exception\RulesException;
+
+class UnknownConstantException extends RulesException {
+
+}

src/Math/Exception/UnknownFunctionException.php

@@ -0,0 +1,14 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\rules\Math\Exception\UnknownFunctionException.
+ */
+
+namespace Drupal\rules\Math\Exception;
+
+use Drupal\rules\Exception\RulesException;
+
+class UnknownFunctionException extends RulesException {
+
+}

src/Math/Exception/UnknownOperatorException.php

@@ -0,0 +1,14 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\rules\Math\Exception\UnknownOperatorException.
+ */
+
+namespace Drupal\rules\Math\Exception;
+
+use Drupal\rules\Exception\RulesException;
+
+class UnknownOperatorException extends RulesException {
+
+}

src/Math/Exception/UnknownTokenException.php

@@ -0,0 +1,14 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\rules\Math\Exception\UnknownTokenException.
+ */
+
+namespace Drupal\rules\Math\Exception;
+
+use Drupal\rules\Exception\RulesException;
+
+class UnknownTokenException extends RulesException {
+
+}

src/Math/Exception/UnknownVariableException.php

@@ -0,0 +1,14 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\rules\Math\Exception\UnknownVariableException.
+ */
+
+namespace Drupal\rules\Math\Exception;
+
+use Drupal\rules\Exception\RulesException;
+
+class UnknownVariableException extends RulesException {
+
+}