parsii.eval

Class BinaryFunction

java.lang.Object

parsii.eval.BinaryFunction

All Implemented Interfaces:

Function

public abstract class BinaryFunction
extends Object
implements Function

Represents a binary function.

A binary function has two arguments which are always evaluated in order to compute the final result.

Constructor Summary

Constructors

Constructor and Description
BinaryFunction()

Method Summary

Modifier and Type	Method and Description
protected abstract double	eval(double a, double b) Performs the computation of the binary function
double	eval(List<Expression> args) Executes the function with the given arguments.
int	getNumberOfArguments() Returns the number of expected arguments.
boolean	isNaturalFunction() A natural function returns the same output for the same input.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BinaryFunction

public BinaryFunction()

Method Detail

getNumberOfArguments

public int getNumberOfArguments()

Description copied from interface: Function

Returns the number of expected arguments.

If the function is called with a different number of arguments, an error will be created

In order to support functions with a variable number of arguments, a negative number can be returned. This will essentially disable the check.

Specified by:

getNumberOfArguments in interface Function

Returns:

the number of arguments expected by this function or a negative number to indicate that this function accepts a variable number of arguments

eval

public double eval(List<Expression> args)

Description copied from interface: Function

Executes the function with the given arguments.

The arguments need to be evaluated first. This is not done externally to permit functions to perform lazy evaluations.

Specified by:

eval in interface Function

Parameters:

args - the arguments for this function. The length of the given list will exactly match getNumberOfArguments

Returns:

the result of the function evaluated with the given arguments

eval

protected abstract double eval(double a,
                               double b)

Performs the computation of the binary function

Parameters:

a - the first argument of the function

b - the second argument of the function

Returns:

the result of calling the function with a and b

isNaturalFunction

public boolean isNaturalFunction()

Description copied from interface: Function

A natural function returns the same output for the same input.

All classical mathematical functions are "natural". A function which reads user input is not natural, as the function might return different results depending on the users input

Specified by:

isNaturalFunction in interface Function

Returns:

true if the function returns the same output for the same input, false otherwise