edu.jmu.decaf

Class SymbolTable

java.lang.Object

edu.jmu.decaf.SymbolTable

public class SymbolTable
extends Object

Stores name-to-symbol-info mappings for a single lexical scope. Symbol tables are generated using a simple AST traversal algorithm, and are used during code generation to look up type and location information for individual symbols.

Constructor Summary

Constructors

Constructor and Description
SymbolTable() Create a new, empty symbol table with no parent table.
SymbolTable(SymbolTable parent) Create a new, empty symbol table.

Method Summary

Modifier and Type	Method and Description
List<Symbol>	getAllSymbols() Gets all symbols accessible in this scope, which includes all symbols defined at this level (from getSymbols()) plus all symbols defined in any parent symbol table.
List<Symbol>	getInheritedSymbols() Gets all symbols accessible in this scope that are not defined in this scope; i.e., all symbols that are defined in a parent table.
List<Symbol>	getSymbols() Gets all symbols defined defined in this scope, in the order in which they were added.
void	insert(String name, Symbol symbol) Inserts a new symbol into the symbol table
Symbol	lookup(String name) Retrieves symbol information for a given symbol name.
int	size() Get accessible symbol count
String	toString() Builds a nicely-formatted list of new symbols declared from this scope.
String	toString(int level) Builds a nicely-formatted list of new symbols declared in this scope.

Methods inherited from class java.lang.Object

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

Constructor Detail

SymbolTable

public SymbolTable()

Create a new, empty symbol table with no parent table.

SymbolTable

public SymbolTable(SymbolTable parent)

Create a new, empty symbol table.

Parameters:

parent - Reference to parent table for enclosing scope.

Method Detail

insert

public void insert(String name,
                   Symbol symbol)
            throws InvalidProgramException

Inserts a new symbol into the symbol table

Parameters:

name - Decaf symbol name

symbol - Symbol information

Throws:

InvalidProgramException - Thrown if the symbol is already defined

lookup

public Symbol lookup(String name)
              throws InvalidProgramException

Retrieves symbol information for a given symbol name.

Parameters:

name - Decaf symbol name

Returns:

Symbol information from either this table or a parent table

Throws:

InvalidProgramException - Thrown if the symbol is not found

size

public int size()

Get accessible symbol count

Returns:

Count of all symbols accessible in this scope

getSymbols

public List<Symbol> getSymbols()

Gets all symbols defined defined in this scope, in the order in which they were added.

Returns:

List of all symbols defined in this scope

getInheritedSymbols

public List<Symbol> getInheritedSymbols()

Gets all symbols accessible in this scope that are not defined in this scope; i.e., all symbols that are defined in a parent table.

Returns:

List of symbols accessible but not defined in this scope

getAllSymbols

public List<Symbol> getAllSymbols()

Gets all symbols accessible in this scope, which includes all symbols defined at this level (from getSymbols()) plus all symbols defined in any parent symbol table.

Returns:

List of symbols accessible in this scope

toString

public String toString()

Builds a nicely-formatted list of new symbols declared from this scope.

Overrides:

toString in class Object

toString

public String toString(int level)

Builds a nicely-formatted list of new symbols declared in this scope.

Parameters:

level - Number of two-space indentations before each symbol.

Returns:

Formated symbol table as a string