org.antlr.symtab

Interface Scope

All Known Implementing Classes:

BaseScope, ClassSymbol, DataAggregateSymbol, FunctionSymbol, GlobalScope, LocalScope, MethodSymbol, PredefinedScope, SymbolWithScope

public interface Scope

A scope is a dictionary of symbols that are grouped together by some lexical construct in the input language. Examples include structs, functions, {...} code blocks, argument lists, etc... Scopes all have an enclosing scope that encloses them lexically. In other words, am I wrapped in a class? a function? a {...} code block? This is distinguished from the parent scope. The parent scope is usually the enclosing scope, but in the case of inheritance, it is the superclass rather than the enclosing scope. Otherwise, the global scope would be considered the parent scope of a class. When resolving symbols, we look up the parent scope chain not the enclosing scope chain. For convenience of code using this library, I have added a bunch of methods one can use to get lots of useful information from a scope, but they don't necessarily define what a scope is.

Method Summary

Modifier and Type	Method and Description
void	define(Symbol sym) Define a symbol in this scope, throw IllegalArgumentException if sym already defined in this scope.
List<? extends Symbol>	getAllSymbols() Return all symbols found in all nested scopes.
List<Scope>	getEnclosingPathToRoot() Return (inclusive) list of all scopes on path to root scope.
Scope	getEnclosingScope() Scope in which this scope defined.
String	getName() Often scopes have names like function or class names.
List<Scope>	getNestedScopedSymbols() Return all immediately enclosed scoped symbols in insertion order.
List<Scope>	getNestedScopes() Return a list of scopes nested within this scope.
int	getNumberOfSymbols() Number of symbols in this specific scope
Scope	getParentScope() Where to look next for symbols if just one parent; superclass or enclosing scope.
List<Scope>	getParentScopes() Multiple superclass or interface implementations and the like...
Symbol	getSymbol(String name) Get symbol if name defined within this specific scope
Set<String>	getSymbolNames() Return the set of names associated with all symbols in the scope.
List<? extends Symbol>	getSymbols() Return the symbols defined within this scope.
void	nest(Scope scope) Add a nested local scope to this scope; it's like define() but for non SymbolWithScope objects.
Symbol	resolve(String name) Look up name in this scope or recursively in parent scope if not here
void	setEnclosingScope(Scope s) What scope encloses this scope.
String	toQualifierString(String separator) Return scopes from to current with separator in between

Method Detail

getName

String getName()

Often scopes have names like function or class names. For unnamed scopes like code blocks, you can just return "local" or something.

getParentScope

Scope getParentScope()

Where to look next for symbols if just one parent; superclass or enclosing scope.

getParentScopes

List<Scope> getParentScopes()

Multiple superclass or interface implementations and the like...

getEnclosingScope

Scope getEnclosingScope()

Scope in which this scope defined. null if no enclosing scope

setEnclosingScope

void setEnclosingScope(Scope s)

What scope encloses this scope. E.g., if this scope is a function, the enclosing scope could be a class. The BaseScope class automatically adds this to nested scope list of s.

define

void define(Symbol sym)
     throws IllegalArgumentException

Define a symbol in this scope, throw IllegalArgumentException if sym already defined in this scope. This alters sym: 1. Set insertion order number of sym 2. Set sym's scope to be the scope. The order in which symbols are defined must be preserved so that getSymbols() returns the list in definition order.

Throws:

IllegalArgumentException

resolve

Symbol resolve(String name)

Look up name in this scope or recursively in parent scope if not here

getSymbol

Symbol getSymbol(String name)

Get symbol if name defined within this specific scope

nest

void nest(Scope scope)
   throws IllegalArgumentException

Add a nested local scope to this scope; it's like define() but for non SymbolWithScope objects. E.g., a FunctionSymbol will add a LocalScope for its block via this method.

Throws:

IllegalArgumentException - if you pass in a SymbolWithScope.

getNestedScopes

List<Scope> getNestedScopes()

Return a list of scopes nested within this scope. It has both ScopedSymbols and scopes without symbols, such as LocalScopes. This returns a superset or same set as getNestedScopedSymbols(). ScopedSymbols come first then all non-ScopedSymbols Scope objects. Insertion order is used within each sublist.

getEnclosingPathToRoot

List<Scope> getEnclosingPathToRoot()

Return (inclusive) list of all scopes on path to root scope. The first element is the current scope and the last is the root scope.

getNestedScopedSymbols

List<Scope> getNestedScopedSymbols()

Return all immediately enclosed scoped symbols in insertion order. E.g., a class would return all nested classes and any methods. There does not have to be an explicit pointer to the nested scopes. This method generally searches the list of symbols looking for symbols that implement Scope. Gets only those scopes that are in the symbols list of "this" scope. E.g., does not get local scopes within a function. This returns a subset or same set as getNestedScopes().

getSymbols

List<? extends Symbol> getSymbols()

Return the symbols defined within this scope. The order of insertion into the scope is the order returned in this list.

getAllSymbols

List<? extends Symbol> getAllSymbols()

Return all symbols found in all nested scopes. The order of insertion into the scope is the order returned in this list for each scope. The scopes are traversed in the order in which they are encountered in the input.

getSymbolNames

Set<String> getSymbolNames()

Return the set of names associated with all symbols in the scope.

getNumberOfSymbols

int getNumberOfSymbols()

Number of symbols in this specific scope

toQualifierString

String toQualifierString(String separator)

Return scopes from to current with separator in between