com.scriptbasic.memory

Class MixedBasicVariableMap

java.lang.Object

com.scriptbasic.memory.BasicLocalVariableMap

com.scriptbasic.memory.MixedBasicVariableMap

All Implemented Interfaces:

HierarchicalVariableMap, LocalVariableMap, VariableMap

public class MixedBasicVariableMap
extends BasicLocalVariableMap
implements HierarchicalVariableMap

Handle the global and the local variable maps. If a variable exists, defined in the local variable map, then that variable is used, otherwise the global variable map is used.

Author:

Peter Verhas date June 22, 2012

Constructor Summary

Constructors

Constructor and Description
MixedBasicVariableMap()

Method Summary

Methods

Modifier and Type	Method and Description
protected String	converted(String name) Converts the name of a variable in a way that if the name 'a' and name 'b' results the same string converted then 'a' and 'b' are treated from some aspects as the same variable name.
void	createVariablesOnTheFly() Inform the object that variables have to be created on the fly without previous proper registration.
void	defaultVariableScopeShallBeGlobal() Inform the object that when a variable is created on the fly without prior declaration that would have specified if the variable is local or global, then the variable has to be global by default.
void	defaultVariableScopeShallBeLocal() Inform the object that when a variable is created on the fly without prior declaration that would have specified if the variable is local or global, then the variable has to be local by default.
VariableMap	getGlobalMap()
Set<String>	getVariableNameSet() Get the set of the variables stored in the variable map so that the caller can iterate through the variables.
RightValue	getVariableValue(String variableName) Get the value of a variable.
void	registerGlobalVariable(String variableName) Register a variable as a global variable.
void	requireVariableDeclaration() Inform the object that variables should not be created on the fly, but first a variable has to be registered and can only be used afterwards.
void	setCaseFreak() Tell the object that the variable names has to be cased only one way.
void	setCaseIgnorant() Tell the object that the variable handling is case insensitive.
void	setCaseSensitive() Tell the object that the variable names are handled in a case sensitive way.
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.

Methods inherited from class com.scriptbasic.memory.BasicLocalVariableMap

currentScopeIsGlobal, dropFrame, isGlobal, isLocal, newFrame, registerLocalVariable

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.scriptbasic.interfaces.LocalVariableMap

dropFrame, newFrame, registerLocalVariable

Methods inherited from interface com.scriptbasic.interfaces.VariableMap

getVariableNameSet

Constructor Detail

MixedBasicVariableMap

public MixedBasicVariableMap()

Method Detail

getGlobalMap

public VariableMap getGlobalMap()

Specified by:

getGlobalMap in interface HierarchicalVariableMap

getVariableValue

public RightValue getVariableValue(String variableName)
                            throws ExecutionException

Description copied from interface: VariableMap

Get the value of a variable.

Specified by:

getVariableValue in interface VariableMap

Overrides:

getVariableValue in class BasicLocalVariableMap

Returns:

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

Throws:

ExecutionException

variableExists

public Boolean variableExists(String variableName)
                       throws ExecutionException

Description copied from interface: VariableMap

Checks that a variable exists in this map.

Specified by:

variableExists in interface VariableMap

Overrides:

variableExists in class BasicLocalVariableMap

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

public Boolean variableDefined(String variableName)
                        throws ExecutionException

Description copied from interface: VariableMap

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

Specified by:

variableDefined in interface VariableMap

Overrides:

variableDefined in class BasicLocalVariableMap

Returns:

true if the variable exists and has a defined value.

Throws:

ExecutionException

requireVariableDeclaration

public void requireVariableDeclaration()

Inform the object that variables should not be created on the fly, but first a variable has to be registered and can only be used afterwards.

createVariablesOnTheFly

public void createVariablesOnTheFly()

Inform the object that variables have to be created on the fly without previous proper registration. This is the usual BASIC way that BASIC programmers got used to, though this is more dangerous.

Nevertheless this is the default behavior.

defaultVariableScopeShallBeLocal

public void defaultVariableScopeShallBeLocal()

Inform the object that when a variable is created on the fly without prior declaration that would have specified if the variable is local or global, then the variable has to be local by default.

This is the safer solution and this is the default, since there is no previous BASIC style in this aspect.

defaultVariableScopeShallBeGlobal

public void defaultVariableScopeShallBeGlobal()

Inform the object that when a variable is created on the fly without prior declaration that would have specified if the variable is local or global, then the variable has to be global by default.

This is generally dangerous, however it is up to the programmer embedding the interpreter to his/her application.

registerGlobalVariable

public void registerGlobalVariable(String variableName)
                            throws ExecutionException

Description copied from interface: LocalVariableMap

Register a variable as a global variable. This is needed when an implementing class manages the global as well as the local variables.

Interpreters handle variables differently. When a variable is not defined using some keyword as 'LOCAL' or 'GLOBAL' then the interpreter may treat the variable default local, may treat default global or may raise error.

This method can be used to declare that a variable is used in the local environment referring to the global variable.

Specified by:

registerGlobalVariable in interface LocalVariableMap

Overrides:

registerGlobalVariable in class BasicLocalVariableMap

Throws:

ExecutionException

setVariable

public void setVariable(String variableName,
               RightValue rightValue)
                 throws ExecutionException

Description copied from interface: VariableMap

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.

Specified by:

setVariable in interface VariableMap

Overrides:

setVariable in class BasicLocalVariableMap

rightValue - the new value of the variable

Throws:

ExecutionException

setCaseSensitive

public void setCaseSensitive()

Tell the object that the variable names are handled in a case sensitive way. It means that the variables 'vaRIable' and 'variABLE' are two different variables and can live in the global or the actual local variable name space along with each other in peace.

It is not recommended to use this mode, however most modern programming languages do this.

setCaseFreak

public void setCaseFreak()

Tell the object that the variable names has to be cased only one way. It means that there can not be a variable named "vaRIable' and 'variABLE' at the same time.

It is the recommended behavior, however BASIC implementations rarely exhibit such variable name handling this is not the default.

setCaseIgnorant

public void setCaseIgnorant()

Tell the object that the variable handling is case insensitive. It means that the variables 'vaRIable' and 'variABLE' denote the same variable.

It is not recommended to use this mode, however most BASIC implementation do this. This is the default behavior.

getVariableNameSet

public Set<String> getVariableNameSet()

Description copied from interface: VariableMap

Get the set of the variables stored in the variable map so that the caller can iterate through the variables.

Specified by:

getVariableNameSet in interface VariableMap

Returns:

converted

protected String converted(String name)

Converts the name of a variable in a way that if the name 'a' and name 'b' results the same string converted then 'a' and 'b' are treated from some aspects as the same variable name. The generic approach is simply upper casing.

Parameters:

name -

Returns: