Expression is used to represent math calculations that can be evaluated into float numbers. Expressions are usually entered as text representations similar to Java or C# expressions. Expressions may be nested and may contain variables. The variable "t" always represents time, and is always bound to deltaTime during expression evaluation. Expressions are used throughout RAIN in Goal Oriented Behavior and Behavior Trees. More...

Public Types
enum	OperatorType
	OperatorType represents standard math operators include addition, subtraction, multiplication, and division Support is not currently included for mod or remainder operations. More...
Public Member Functions
	Expression ()
	Default constructor. Initializes to an empty invalid NO_OP expression.
void	Clear ()
	Clear any nested expressions and reset state to an empty invalid NO_OP.
void	RenameVariable (string originalName, string newName)
	Rename a variable in this and all nested expressions.
void	SetConstant (float k)
	Set the expression to represent a constant value. This expression will always evaluate to the constant.
void	SetVariable (string variable)
	Set the expression to represent a variable value. Only a single variable name will be entered. The variable is not checked against the existing variable context, but is just assumed to be bound at runtime. A variable name may be any string, although using non standard (Java/C#) variable names will result in expressions that can't be rewritten and reparsed.
void	SetTimeExpression ()
	Set the expression to represent time. This expression will evaluate to the deltaTime value passed into the Evaluate method.
void	SetInvalid ()
	Invalidate the Expression. Evaluation will return NaN (not a number) for invalid Expressions.
void	SetExpression (Expression expr1, OperatorType operatorType, Expression expr2, bool isAtomic)
	SetExpression will directly set a complex expression as a left-hand-side (lhs, an infix operator, and a right-hand-side (rhs). isAtomic is used to mark the expression so that its terms do not get reordered on subsequent calls to FixOperatorPrecedence. This is equivalent to adding parenthesis around the expression.
float	Evaluate (float deltaTime, ActionContext actionContext)
	Evaluate calculates the value of the value of this expression as a float.
float	Evaluate (float deltaTime, float minValue, float maxValue, ActionContext actionContext)
	Evaluate calculates the value of the value of this expression as a float.
followed by a term with a lower precedence the expression tree may be rearranged </summary > void	FixOperatorPrecedence ()
void	SetAtomic (bool isAtomic)
	SetAtomic marks an expression so that it can't be changed by the FixOperatorPrecedence function. This is the equivalent of surrounding the expression with parenthesis.
override string	ToString ()
	ToString() will return a string representation of the Expression which may differ from the original text parsed to create this expression.
Properties
bool	IsConstant `[get]`
	Does the expression represent a constant?
bool	IsVariable `[get]`
	Does the expression represent a variable?
bool	IsComplex `[get]`
	Does the expression represent a complex expression?
bool	IsTime `[get]`
	Does the expression represent delta time (t)?
bool	IsValid `[get]`
	Is the expression valid and can it be evaluated successfully?
string	VariableName `[get]`
	If the expression represents a variable, returns the variable name Returns null otherwise.
string	ExpressionAsEntered `[get, set]`
	ExpressionAsEntered returns the text used to initially describe the Expression, if the expression was created from parsing a script or manual entry. This is useful when supporting user editing of invalid expressions.

Detailed Description

Expression is used to represent math calculations that can be evaluated into float numbers. Expressions are usually entered as text representations similar to Java or C# expressions. Expressions may be nested and may contain variables. The variable "t" always represents time, and is always bound to deltaTime during expression evaluation. Expressions are used throughout RAIN in Goal Oriented Behavior and Behavior Trees.

Member Enumeration Documentation

enum RAIN.Belief.Expression.OperatorType

OperatorType represents standard math operators include addition, subtraction, multiplication, and division Support is not currently included for mod or remainder operations.

Constructor & Destructor Documentation

RAIN.Belief.Expression.Expression ( )

Default constructor. Initializes to an empty invalid NO_OP expression.

Member Function Documentation

void RAIN.Belief.Expression.Clear ( )

Clear any nested expressions and reset state to an empty invalid NO_OP.

float RAIN.Belief.Expression.Evaluate	(	float	deltaTime,
		ActionContext	actionContext
	)

Evaluate calculates the value of the value of this expression as a float.

Parameters:

deltaTime	time to use for expressions utilizing the variable "t"
actionContext	ActionContext to use for variable expressions

Returns:

float RAIN.Belief.Expression.Evaluate	(	float	deltaTime,
		float	minValue,
		float	maxValue,
		ActionContext	actionContext
	)

Evaluate calculates the value of the value of this expression as a float.

Parameters:

deltaTime	time to use for expressions utilizing the variable "t"
actionContext	ActionContext to use for variable expressions

Returns:

void RAIN.Belief.Expression.RenameVariable	(	string	originalName,
		string	newName
	)

Rename a variable in this and all nested expressions.

Parameters:

originalName	The name of the variable to rename
newName	The new name to replace the original variable name

void RAIN.Belief.Expression.SetAtomic ( bool isAtomic )

SetAtomic marks an expression so that it can't be changed by the FixOperatorPrecedence function. This is the equivalent of surrounding the expression with parenthesis.

Parameters:

isAtomic

void RAIN.Belief.Expression.SetConstant ( float k )

Set the expression to represent a constant value. This expression will always evaluate to the constant.

Parameters:

k	The constant value to use

void RAIN.Belief.Expression.SetExpression	(	Expression	expr1,
		OperatorType	operatorType,
		Expression	expr2,
		bool	isAtomic
	)

SetExpression will directly set a complex expression as a left-hand-side (lhs, an infix operator, and a right-hand-side (rhs). isAtomic is used to mark the expression so that its terms do not get reordered on subsequent calls to FixOperatorPrecedence. This is equivalent to adding parenthesis around the expression.

Parameters:

expr1	The lhs expression
operatorType	Mathematical operator
expr2	The rhs expression
isAtomic	A value indicating whether FixOperatorPrecedence can reorder terms.

void RAIN.Belief.Expression.SetInvalid ( )

Invalidate the Expression. Evaluation will return NaN (not a number) for invalid Expressions.

void RAIN.Belief.Expression.SetTimeExpression ( )

Set the expression to represent time. This expression will evaluate to the deltaTime value passed into the Evaluate method.

void RAIN.Belief.Expression.SetVariable ( string variable )

Set the expression to represent a variable value. Only a single variable name will be entered. The variable is not checked against the existing variable context, but is just assumed to be bound at runtime. A variable name may be any string, although using non standard (Java/C#) variable names will result in expressions that can't be rewritten and reparsed.

Parameters:

variable A variable name to use when binding at runtime. Variable names are case sensitive.

override string RAIN.Belief.Expression.ToString ( )

ToString() will return a string representation of the Expression which may differ from the original text parsed to create this expression.

Returns:: Returns a text representation of the Expressoin

Property Documentation

string RAIN.Belief.Expression.ExpressionAsEntered [get, set]

ExpressionAsEntered returns the text used to initially describe the Expression, if the expression was created from parsing a script or manual entry. This is useful when supporting user editing of invalid expressions.

bool RAIN.Belief.Expression.IsComplex [get]

Does the expression represent a complex expression?

bool RAIN.Belief.Expression.IsConstant [get]

Does the expression represent a constant?

bool RAIN.Belief.Expression.IsTime [get]

Does the expression represent delta time (t)?

bool RAIN.Belief.Expression.IsValid [get]

Is the expression valid and can it be evaluated successfully?

bool RAIN.Belief.Expression.IsVariable [get]

Does the expression represent a variable?

string RAIN.Belief.Expression.VariableName [get]

If the expression represents a variable, returns the variable name Returns null otherwise.