com.adamcornett.cminus
Class Scope

java.lang.Object
  com.adamcornett.cminus.Scope

public class Scope
extends Object

Represents a variable scope. This implementation is NOT multi-thread safe!

Author:

Adam Cornett

Field Summary

private Set<Scope>	childern
private static Scope	currentScope The current scope that the parser or analyzer is in.
private static int	nextScopeNumber The next scope number ot be issued.
private Scope	parentScope The parent of this scope.
private static Scope	rootScope The root scope.
private static Map<Integer,Scope>	scopeMap A map linking a given scope number to a scope.
private int	scopeNumber The scope number of this Scope.
private SymbolTable	symbols The symbol table for this scope.
private org.antlr.runtime.Token	token The token which is at the start of this scope, usually a function identifier, or a '{' at the beginning of a compound statement

Constructor Summary

Scope(org.antlr.runtime.Token t)
Create a new scope.

Method Summary

void	addChild(Scope s) Add a child scope and set it's parent as this class
static void	cleanEmpty()
private static void	cleanEmpty(Scope s)
static void	clear()
void	delete() Delete this scope and re-assign all childern to parent;
static Scope	getCurrentScope() Get the current scope.
String	getName() Get the name of the scope
Scope	getParent() Get the parent scope
static Scope	getScope(Integer sn) Get the Scope object with the given scope number.
int	getScopeNumber() Get this scope's number
SymbolTable	getSymbols() Get the symbol table for this scope
org.antlr.runtime.Token	getToken() Get the token this scope started on.
static Symbol	lookup(String s) Looks up a symbol with the name s in the current scope
static Symbol	lookup(String s, Scope scope) Look up a symbol in a specified scope
static void	popScope() Pops the current scope, replacing with it with its parent, unless it is the root scope, which cannot be popped.
static String	print() Prints all symbols in the table.
static void	pushScope(Scope s) Add a new scope to the stack.
static void	pushSymbol(Symbol s) Add a symbol to the current scope.
void	removeChild(Scope s) Remove a child scope
static void	setScope(Integer scopeNumber) Lookup a given scope and set it as the current scope.
void	setSymbols(SymbolTable symbols) Set the symbol table for this scope.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

currentScope

private static Scope currentScope

The current scope that the parser or analyzer is in.

nextScopeNumber

private static int nextScopeNumber

The next scope number ot be issued.

rootScope

private static Scope rootScope

The root scope.

scopeMap

private static Map<Integer,Scope> scopeMap

A map linking a given scope number to a scope.

parentScope

private Scope parentScope

The parent of this scope.

childern

private Set<Scope> childern

scopeNumber

private final int scopeNumber

The scope number of this Scope.

symbols

private SymbolTable symbols

The symbol table for this scope.

token

private final org.antlr.runtime.Token token

The token which is at the start of this scope, usually a function identifier, or a '{' at the beginning of a compound statement

Constructor Detail

Scope

public Scope(org.antlr.runtime.Token t)

Create a new scope.

Parameters:

t - The token which the scope starts at.

Method Detail

cleanEmpty

public static void cleanEmpty()

getCurrentScope

public static Scope getCurrentScope()

Get the current scope.

Returns:

The current scope.

getScope

public static Scope getScope(Integer sn)

Get the Scope object with the given scope number.

Parameters:

sn - The scope number to look up.

Returns:

The scope object with the given number, or NULL if it cannot be found.

lookup

public static Symbol lookup(String s)

Looks up a symbol with the name s in the current scope

Parameters:

s - The name of the symbol to look for.

Returns:

The symbol with the name s in the current scope, or NULL if it does not exist.

lookup

public static Symbol lookup(String s,
                            Scope scope)

Look up a symbol in a specified scope

Parameters:

s - The name of the symbol to look for

scope - The scope to search for the symbol in

Returns:

The symbol with the name s in the current scope, or NULL if it does not exist.

popScope

public static void popScope()

Pops the current scope, replacing with it with its parent, unless it is the root scope, which cannot be popped.

print

public static String print()

Prints all symbols in the table.

Returns:

The string representation of all symbols in this Scope's symbol table.

pushScope

public static void pushScope(Scope s)

Add a new scope to the stack. The current scope is made the parent of s and s becomes the current scope.

Parameters:

s - The scope to push.

pushSymbol

public static void pushSymbol(Symbol s)

Add a symbol to the current scope.

Parameters:

s - The symbol to be added.

setScope

public static void setScope(Integer scopeNumber)

Lookup a given scope and set it as the current scope.

Parameters:

scopeNumber -

cleanEmpty

private static void cleanEmpty(Scope s)

addChild

public void addChild(Scope s)

Add a child scope and set it's parent as this class

Parameters:

s -

delete

public void delete()

Delete this scope and re-assign all childern to parent;

getName

public String getName()

Get the name of the scope

Returns:

A string representation of the scope

getParent

public Scope getParent()

Get the parent scope

Returns:

The scope which is the parent for this scope

getScopeNumber

public int getScopeNumber()

Get this scope's number

Returns:

The unique scope number for this scope

getSymbols

public SymbolTable getSymbols()

Get the symbol table for this scope

Returns:

The symbol table for this scope.

getToken

public org.antlr.runtime.Token getToken()

Get the token this scope started on.

Returns:

A token that caused the start of the scope.

removeChild

public void removeChild(Scope s)

Remove a child scope

Parameters:

s -

setSymbols

public void setSymbols(SymbolTable symbols)

Set the symbol table for this scope.

Parameters:

symbols - The new Symbol Table

toString

public String toString()

Overrides:

toString in class Object

clear

public static void clear()