The operator class, a Node subclass, is a generalized Node extended to perform operations on other nodes.

The operator class, unlike the Node class, is able to modify nodes other than itself. The operator class behaves in most ways identically to the Node class (its parent class) but may also "Make" itself from a stack of other Nodes. The definition of "Make" varies from class to class but the resulting node must always be able to evaluate itself after the Make process has been completed. Operators have two additional responsibilities as well: they must return a precedence (to tell the parser the proper order of operators) and a description (usually corresponding to the algebraic representation of the operator).

Source:

node.hh:95

Author:

Jonathan Kitchens

Version:

v0.9

Entity	Inherited From	Type	Scope	Short Description
~Operator		destructor	public	automatically generated
Operator		constructor	public	automatically generated
Operator		constructor	public	automatically generated
Copy		method	public	Same function as in the Node superclass; see Node for details.
Evaluate		method	public	Same function as in the Node superclass; see Node for details.
GetDescription		method	public	Returns the algebraic form/description of the operator.
GetPrecedence		method	public	Gives the precedence of this operator.
Make		method	public	Attempts to Make this operator from a stack of nodes.
operator =		operator	public	automatically generated
Print		method	public	Same function as in the Node superclass; see Node for details.

automatically generated

Source:

node.hh

Code:

public ~ Operator ( )

automatically generated

Source:

node.hh

Code:

public Operator (

)

automatically generated

Source:

node.hh

Code:

public Operator (

const Operator & )

Same function as in the Node superclass; see Node for details.

Source:

node.hh:122

Author:

Jonathan Kitchens

Version:

v0.9

See Also:

Node

Code:

public virtual Node * Copy (

) = 0

Same function as in the Node superclass; see Node for details.

Source:

node.hh:104

Author:

Jonathan Kitchens

Version:

v0.9

See Also:

Node

Code:

public virtual Number * Evaluate (

) = 0

Returns the algebraic form/description of the operator.

This function returns a string describing the function of the operator. In general, this string will be used later to recognize the operator in a parse stream, so it should be the same as the algebraic representation of the operator (ie, the description for a Plus operator should be "+"). See the ParseType for an example of how this description is used to find operators in a stream.

Source:

node.hh:141

Author:

Jonathan Kitchens

Version:

v0.9

Returns:

a string describing the function of the operator

See Also:

ParseType, ParseOps

Code:

public virtual string GetDescription (

) const = 0

Gives the precedence of this operator.

This function returns the precedence (relative importance) of the operator. This will help the ParseType use the correct order of operations in "Make"ing the operators in the input string. The precedence is a double here because this allows for a nearly infinite number of operators with a unique order. Thus, inserting a new operator with a precedence between that of two others can always be accomplished without needing to change every operator's precedence.

Source:

node.hh:161

Author:

Jonathan Kitchens

Version:

v0.9

Returns:

a double containing the precedence of this operator

See Also:

ParseType, ParseOps

Code:

public virtual double GetPrecedence (

) const = 0

Attempts to Make this operator from a stack of nodes.

The Make function allows the operator creation and processing to be done seperately. Each operator is free to modify the stack as it wishes (the definition of an operator), allowing postfix, prefix, unary, binary, multi-argument, indefinite-argument, and many other types of operators to be implemented easily. The only requirement on the Make() function is that, afterwards, the Operator Node should be able to be evaluated. The Make function has the option to return true or false to report whether or not the operator was able to initialize.

Source:

node.hh:186

Author:

Jonathan Kitchens

Version:

v0.9

Param:

myNodeStack

a stack of Nodes which the operator may modify at will

Returns:

true if the operator is ready to be evaluated, false otherwise

See Also:

ParseOps, Parser

Code:

public virtual bool Make (

stack < Node * > & myNodeStack ) = 0

automatically generated

Source:

node.hh

Code:

public Operator & operator = (

const Operator & )

Same function as in the Node superclass; see Node for details.

Source:

node.hh:113

Author:

Jonathan Kitchens

Version:

v0.9

See Also:

Node

Code:

public virtual void Print (

ostream & out ) const = 0