com.scriptbasic.memory

Class BasicLocalVariableMap

java.lang.Object

com.scriptbasic.memory.BasicLocalVariableMap

All Implemented Interfaces:

LocalVariableMap, VariableMap

Direct Known Subclasses:

MixedBasicVariableMap

public class BasicLocalVariableMap
extends Object
implements LocalVariableMap

Handle the local variable in a hierarchical stack of Maps

Author:

Peter Verhas date June 22, 2012

Constructor Summary

Constructors

Constructor and Description
BasicLocalVariableMap()

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.
boolean	currentScopeIsGlobal() Returns true if the current scope is global, there no no any local stack frame open.
void	dropFrame() Drop the current frame and pop off the map from the top of the stack.
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.
boolean	isGlobal(String variableName)
boolean	isLocal(String variableName)
void	newFrame() Push the actual Map onto the stack of maps and create a new empty stack.
void	registerGlobalVariable(String variableName) Register a variable as a global variable.
void	registerLocalVariable(String variableName) Define the variable as a local variable in a local environment.
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 java.lang.Object

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

Methods inherited from interface com.scriptbasic.interfaces.VariableMap

getVariableNameSet

Constructor Detail

BasicLocalVariableMap

public BasicLocalVariableMap()

Method Detail

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

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

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

Returns:

true if the variable exists and has a defined value.

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

rightValue - the new value of the variable

Throws:

ExecutionException

newFrame

public void newFrame()

Description copied from interface: LocalVariableMap

Push the actual Map onto the stack of maps and create a new empty stack. This is what a program has to do when a function is called. The local variables (if any) are pushed on the stack and a new stack frame is opened.

Specified by:

newFrame in interface LocalVariableMap

dropFrame

public void dropFrame()

Description copied from interface: LocalVariableMap

Drop the current frame and pop off the map from the top of the stack. This is what programs have to do when a RETURN is executed from a function.

Specified by:

dropFrame in interface LocalVariableMap

currentScopeIsGlobal

public boolean currentScopeIsGlobal()

Returns true if the current scope is global, there no no any local stack frame open.

Returns:

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

Throws:

ExecutionException

registerLocalVariable

public void registerLocalVariable(String variableName)
                           throws ExecutionException

Description copied from interface: LocalVariableMap

Define the variable as a local variable in a local environment. For more information see the documentation of the method

Specified by:

registerLocalVariable in interface LocalVariableMap

Throws:

ExecutionException

isGlobal

public boolean isGlobal(String variableName)
                 throws ExecutionException

Throws:

ExecutionException

isLocal

public boolean isLocal(String variableName)
                throws ExecutionException

Throws:

ExecutionException

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:

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.

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: