com.scriptbasic.interfaces

Interface VariableMap

All Known Subinterfaces:

HierarchicalVariableMap, LocalVariableMap

All Known Implementing Classes:

BasicLocalVariableMap, MixedBasicVariableMap

public interface VariableMap

Manage local or global variables. One Map manages the global variables in a BASIC program. There is a map for each local level of function calls storing the local variables. This interface is also implemented by the MixedBasicVariableMap that manages the global and the local variables transparently.

The methods may throw ExecutionException. The interface provides this possibility to implement features like denying case sensitive reuse of variable names. For example jScriptBasic does not allow you to use the variable Apple is ever you already used apple. In other basic implementations the casing is insensitive and the two variable names are the same. Other languages treat Apple and apple as two different variables. jScriptBasic believes that both practices are bad.

Author:

Peter Verhas

Method Summary

Methods

Modifier and Type	Method and Description
RightValue	getVariableValue(String variableName) Get the value of a variable.
void	setVariable(String variableName, RightValue rightValue) Set the value of the variable.
Boolean	variableDefined(String variableName) Checks that a variable exists and has a defined value in this map.
Boolean	variableExists(String variableName) Checks that a variable exists in this map.

Method Detail

getVariableValue

RightValue getVariableValue(String variableName)
                            throws ExecutionException

Get the value of a variable.

Parameters:

variableName -

Returns:

the right value the variable has or null if the variable is not defined or does not exists.

Throws:

ExecutionException

variableExists

Boolean variableExists(String variableName)
                       throws ExecutionException

Checks that a variable exists in this map.

Parameters:

variableName -

Returns:

true if the variable exists, even if the variable has undefined value. false if the variable does not exist in this map.

Throws:

ExecutionException

variableDefined

Boolean variableDefined(String variableName)
                        throws ExecutionException

Checks that a variable exists and has a defined value in this map. Undefined value is represented by null.

Parameters:

variableName -

Returns:

true if the variable exists and has a defined value.

Throws:

ExecutionException

setVariable

void setVariable(String variableName,
               RightValue rightValue)
                 throws ExecutionException

Set the value of the variable. If the variable did not exist then the variable is automatically created. If the variable had undefined value then the new value will be the one defined by the argument.

You can set a variable to undefined passing null to this method as rightValue.

Parameters:

variableName -

rightValue - the new value of the variable

Throws:

ExecutionException