Evalutate a parsed mathematical expression. More...

Inheritance diagram for MathParser\Interpreting\Evaluator:

Public Member Functions
	__construct ($variables=null)
	Constructor. More...

	setVariables ($variables)
	Update the variables used for evaluating. More...

	visitExpressionNode (ExpressionNode $node)
	Evaluate an ExpressionNode. More...

	visitNumberNode (NumberNode $node)
	Evaluate a NumberNode. More...

	visitIntegerNode (IntegerNode $node)
	Interface function for visiting IntegerNodes. More...

	visitRationalNode (RationalNode $node)
	Interface function for visiting RationalNodes. More...

	visitVariableNode (VariableNode $node)
	Evaluate a VariableNode. More...

	visitFunctionNode (FunctionNode $node)
	Evaluate a FunctionNode. More...

	visitConstantNode (ConstantNode $node)
	Evaluate a ConstantNode. More...

Private Attributes
	$variables
	mixed[] $variables Key/value pair holding current values of the variables used for evaluating.

Detailed Description

Evalutate a parsed mathematical expression.

Implementation of a Visitor, transforming an AST into a floating point number, giving the value of the expression represented by the AST.

The class implements evaluation of all all arithmetic operators as well as every elementary function and predefined constant recognized by StdMathLexer and StdmathParser.

Example:

$parser = new StdMathParser();
$f = $parser->parse('exp(2x)+xy');
$evaluator = new Evaluator();
$evaluator->setVariables([ 'x' => 1, 'y' => '-1' ]);
result = $f->accept($evaluator);    // Evaluate $f using x=1, y=-1

TODO: handle user specified functions

Constructor & Destructor Documentation

MathParser\Interpreting\Evaluator::__construct ( $variables = null )

Constructor.

Create an Evaluator with given variable values.

Parameters

mixed $variables key-value array of variables with corresponding values.

Member Function Documentation

MathParser\Interpreting\Evaluator::setVariables ( $variables )

Update the variables used for evaluating.

Parameters

array $variables Key/value pair holding current variable values

Return values

void

MathParser\Interpreting\Evaluator::visitConstantNode ( ConstantNode $node )

Evaluate a ConstantNode.

Returns the value of a ConstantNode recognized by StdMathLexer and StdMathParser.

See Also: MathParser::Lexer::StdMathLexer StdMathLexer; MathParser::StdMathParser StdMathParser

Exceptions

UnknownConstantException if the variable respresented by the ConstantNode is not recognized.

Parameters

ConstantNode $node AST to be evaluated

Return values

float

Implements MathParser\Interpreting\Visitors\Visitor.

MathParser\Interpreting\Evaluator::visitExpressionNode ( ExpressionNode $node )

Evaluate an ExpressionNode.

Computes the value of an ExpressionNode x op y where op is one of +, -, *, / or ^

Exceptions

UnknownOperatorException if the operator is something other than +, -, *, / or ^

Parameters

ExpressionNode $node AST to be evaluated

Return values

float

Implements MathParser\Interpreting\Visitors\Visitor.

MathParser\Interpreting\Evaluator::visitFunctionNode ( FunctionNode $node )

Evaluate a FunctionNode.

Computes the value of a FunctionNode f(x), where f is an elementary function recognized by StdMathLexer and StdMathParser.

See Also: MathParser::Lexer::StdMathLexer StdMathLexer; MathParser::StdMathParser StdMathParser

Exceptions

UnknownFunctionException if the function respresented by the FunctionNode is not recognized.

Parameters

FunctionNode $node AST to be evaluated

Return values

float

Implements MathParser\Interpreting\Visitors\Visitor.

MathParser\Interpreting\Evaluator::visitIntegerNode ( IntegerNode $node )

Interface function for visiting IntegerNodes.

Parameters

IntegerNode $node Node to visit.

Implements MathParser\Interpreting\Visitors\Visitor.

MathParser\Interpreting\Evaluator::visitNumberNode ( NumberNode $node )

Evaluate a NumberNode.

Retuns the value of an NumberNode

Parameters

NumberNode $node AST to be evaluated

Return values

float

Implements MathParser\Interpreting\Visitors\Visitor.

MathParser\Interpreting\Evaluator::visitRationalNode ( RationalNode $node )

Interface function for visiting RationalNodes.

Parameters

RationalNode $node Node to visit.

Implements MathParser\Interpreting\Visitors\Visitor.

MathParser\Interpreting\Evaluator::visitVariableNode ( VariableNode $node )

Evaluate a VariableNode.

Returns the current value of a VariableNode, as defined either by the constructor or set using the Evaluator::setVariables() method.

See Also: Evaluator::setVariables() to define the variables

Exceptions

UnknownVariableException if the variable respresented by the VariableNode is not set.

Parameters

VariableNode $node AST to be evaluated

Return values

float

Implements MathParser\Interpreting\Visitors\Visitor.

The documentation for this class was generated from the following file:

src/MathParser/Interpreting/Evaluator.php

Public Member Functions

Private Attributes

Detailed Description

Example:

Constructor & Destructor Documentation

Member Function Documentation