PLMD::lepton::ExpressionProgram Class Reference

An ExpressionProgram is a linear sequence of Operations for evaluating an expression. More...

#include <ExpressionProgram.h>

Public Member Functions
	ExpressionProgram ()
	ExpressionProgram (const ExpressionProgram &program)
	~ExpressionProgram ()
double	evaluate () const
	Evaluate the expression. More...
double	evaluate (const std::map< std::string, double > &variables) const
	Evaluate the expression. More...
int	getNumOperations () const
	Get the number of Operations that make up this program. More...
const Operation &	getOperation (int index) const
	Get an Operation in this program. More...
int	getStackSize () const
	Get the size of the stack needed to execute this program. More...
ExpressionProgram &	operator= (const ExpressionProgram &program)
void	setOperation (int index, Operation *operation)
	Change an Operation in this program. More...

Private Member Functions
	ExpressionProgram (const ParsedExpression &expression)
void	buildProgram (const ExpressionTreeNode &node)

Private Attributes
int	maxArgs
std::vector< Operation * >	operations
int	stackSize

Friends
class	ParsedExpression

Detailed Description

An ExpressionProgram is a linear sequence of Operations for evaluating an expression.

The evaluation is done with a stack. The arguments to each Operation are first taken off the stack in order, then it is evaluated and the result is pushed back onto the stack. At the end, the stack contains a single value, which is the value of the expression.

An ExpressionProgram is created by calling createProgram() on a ParsedExpression.

Constructor & Destructor Documentation

ExpressionProgram() [1/3]

PLMD::ExpressionProgram::ExpressionProgram

(

)

ExpressionProgram() [2/3]

PLMD::ExpressionProgram::ExpressionProgram

(

const ExpressionProgram &

program

)

~ExpressionProgram()

PLMD::ExpressionProgram::~ExpressionProgram

(

)

ExpressionProgram() [3/3]

PLMD::ExpressionProgram::ExpressionProgram ( const ParsedExpression &  expression )

private

Member Function Documentation

buildProgram()

void PLMD::ExpressionProgram::buildProgram ( const ExpressionTreeNode &  node )

private

evaluate() [1/2]

double PLMD::ExpressionProgram::evaluate

(

)

const

Evaluate the expression.

If the expression involves any variables, this method will throw an exception.

evaluate() [2/2]

double PLMD::ExpressionProgram::evaluate

(

const std::map< std::string, double > &

variables

)

const

Evaluate the expression.

Parameters

variables

a map specifying the values of all variables that appear in the expression. If any variable appears in the expression but is not included in this map, an exception will be thrown.

getNumOperations()

int PLMD::ExpressionProgram::getNumOperations

(

)

const

Get the number of Operations that make up this program.

getOperation()

const Operation & PLMD::ExpressionProgram::getOperation

(

int

index

)

const

Get an Operation in this program.

getStackSize()

int PLMD::ExpressionProgram::getStackSize

(

)

const

Get the size of the stack needed to execute this program.

This is the largest number of elements present on the stack at any point during evaluation.

operator=()

ExpressionProgram & PLMD::ExpressionProgram::operator=

(

const ExpressionProgram &

program

)

setOperation()

void PLMD::ExpressionProgram::setOperation	(	int	index,
		Operation *	operation
	)

Change an Operation in this program.

The Operation must have been allocated on the heap with the "new" operator. The ExpressionProgram assumes ownership of it and will delete it when it is no longer needed.

Friends And Related Function Documentation

ParsedExpression

friend class ParsedExpression

friend

Member Data Documentation

maxArgs

int PLMD::lepton::ExpressionProgram::maxArgs

private

operations

std::vector<Operation*> PLMD::lepton::ExpressionProgram::operations

private

stackSize

int PLMD::lepton::ExpressionProgram::stackSize

private

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

• lepton/ExpressionProgram.h
• lepton/ExpressionProgram.cpp