com.google.javascript.jscomp

Class TypedScope

java.lang.Object

com.google.javascript.jscomp.Scope

com.google.javascript.jscomp.TypedScope

All Implemented Interfaces:

StaticTypedScope<JSType>, StaticScope

public class TypedScope
extends Scope
implements StaticTypedScope<JSType>

TypedScope contains information about variables and their types. Scopes can be nested, a scope points back to its parent scope.

TypedScope is also used as a lattice element for flow-sensitive type inference. As a lattice element, a scope is viewed as a map from names to types. A name not in the map is considered to have the bottom type. The join of two maps m1 and m2 is the map of the union of names with JSType.getLeastSupertype(com.google.javascript.rhino.jstype.JSType) to meet the m1 type and m2 type.

See Also:

NodeTraversal, Several methods in this class, such as {@code isBlockScope} throw an exception when called. The reason for this is that we want to shadow methods from the parent class, to avoid calling them accidentally.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
(package private) static interface	TypedScope.TypeResolver

Field Summary

Fields

Modifier and Type	Field and Description
private static com.google.common.base.Predicate<TypedVar>	DECLARATIVELY_UNBOUND_VARS_WITHOUT_TYPES
private boolean	isBottom Whether this is a bottom scope for the purposes of type inference.
private TypedScope	parent
private TypedScope.TypeResolver	typeResolver
private java.util.Map<java.lang.String,TypedVar>	vars

Fields inherited from class com.google.javascript.jscomp.Scope

depth, rootNode

Constructor Summary

Constructors

Modifier	Constructor and Description
private	TypedScope(Node rootNode, boolean isBottom) Creates a empty Scope (bottom of the lattice).
(package private)	TypedScope(TypedScope parent, Node rootNode)

Method Summary

Modifier and Type	Method and Description
(package private) static TypedScope	createGlobalScope(Node rootNode)
(package private) static TypedScope	createLatticeBottom(Node rootNode)
(package private) Var	declare(java.lang.String name, Node nameNode, CompilerInput input) Declares a variable.
(package private) TypedVar	declare(java.lang.String name, Node nameNode, JSType type, CompilerInput input)
(package private) TypedVar	declare(java.lang.String name, Node nameNode, JSType type, CompilerInput input, boolean inferred)
java.lang.Iterable<TypedVar>	getAllSymbols()
Var	getArgumentsVar() Get a unique VAR object to represents "arguments" within this scope
Scope	getClosestHoistScope() If a var were declared in this scope, return the scope it would be hoisted to.
java.util.Iterator<TypedVar>	getDeclarativelyUnboundVarsWithoutTypes()
int	getDepth() The depth of the scope.
(package private) TypedScope	getGlobalScope()
TypedVar	getOwnSlot(java.lang.String name) Like getSlot but does not recurse into parent scopes.
TypedScope	getParent()
StaticTypedScope<JSType>	getParentScope() Returns the scope enclosing this one or null if none.
Node	getRootNode() Gets the container node of the scope.
TypedVar	getSlot(java.lang.String name) Returns any defined slot within this scope for this name.
JSType	getTypeOfThis() Gets the type of this in the current scope.
TypedVar	getVar(java.lang.String name) Returns the variable, may be null
int	getVarCount() Returns number of variables in this scope (excluding the special 'arguments' variable)
(package private) java.lang.Iterable<Var>	getVarIterable() Return an iterable over all of the variables declared in this scope (except the special 'arguments' variable).
java.util.Iterator<TypedVar>	getVars() Return an iterator over all of the variables declared in this scope.
boolean	isBlockScope()
(package private) boolean	isBottom() Whether this is the bottom of the lattice.
boolean	isDeclared(java.lang.String name, boolean recurse) Returns true if a variable is declared.
boolean	isFunctionBlockScope()
boolean	isGlobal() Returns whether this is the global scope.
boolean	isLocal() Returns whether this is a local scope (i.e.
(package private) void	resolveTypes() Resolve all type references.
(package private) void	setTypeResolver(TypedScope.TypeResolver resolver)
(package private) void	undeclare(Var var) Undeclares a variable, to be used when the compiler optimizes out a variable and removes it from the scope.

Methods inherited from class com.google.javascript.jscomp.Scope

isFunctionScope, toString

Methods inherited from class java.lang.Object

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

Field Detail

vars

private final java.util.Map<java.lang.String,TypedVar> vars

parent

private final TypedScope parent

isBottom

private final boolean isBottom

Whether this is a bottom scope for the purposes of type inference.

DECLARATIVELY_UNBOUND_VARS_WITHOUT_TYPES

private static final com.google.common.base.Predicate<TypedVar> DECLARATIVELY_UNBOUND_VARS_WITHOUT_TYPES

typeResolver

private TypedScope.TypeResolver typeResolver

Constructor Detail

TypedScope

TypedScope(TypedScope parent,
           Node rootNode)

TypedScope

private TypedScope(Node rootNode,
                   boolean isBottom)

Creates a empty Scope (bottom of the lattice).

Parameters:

rootNode - Typically a FUNCTION node or the global BLOCK node.

isBottom - Whether this is the bottom of a lattice. Otherwise, it must be a global scope.

Method Detail

createGlobalScope

static TypedScope createGlobalScope(Node rootNode)

createLatticeBottom

static TypedScope createLatticeBottom(Node rootNode)

isBottom

boolean isBottom()

Whether this is the bottom of the lattice.

getDepth

public int getDepth()

Description copied from class: Scope

The depth of the scope. The global scope has depth 0.

Overrides:

getDepth in class Scope

getRootNode

public Node getRootNode()

Description copied from class: Scope

Gets the container node of the scope. This is typically the FUNCTION node or the global BLOCK/SCRIPT node.

Specified by:

getRootNode in interface StaticScope

Overrides:

getRootNode in class Scope

getParent

public TypedScope getParent()

Overrides:

getParent in class Scope

getGlobalScope

TypedScope getGlobalScope()

Overrides:

getGlobalScope in class Scope

getParentScope

public StaticTypedScope<JSType> getParentScope()

Description copied from interface: StaticScope

Returns the scope enclosing this one or null if none.

Specified by:

getParentScope in interface StaticTypedScope<JSType>

Specified by:

getParentScope in interface StaticScope

Overrides:

getParentScope in class Scope

getTypeOfThis

public JSType getTypeOfThis()

Gets the type of this in the current scope.

Specified by:

getTypeOfThis in interface StaticTypedScope<JSType>

declare

Var declare(java.lang.String name,
            Node nameNode,
            CompilerInput input)

Description copied from class: Scope

Declares a variable.

Overrides:

declare in class Scope

Parameters:

name - name of the variable

nameNode - the NAME node declaring the variable

input - the input in which this variable is defined.

declare

TypedVar declare(java.lang.String name,
                 Node nameNode,
                 JSType type,
                 CompilerInput input)

declare

TypedVar declare(java.lang.String name,
                 Node nameNode,
                 JSType type,
                 CompilerInput input,
                 boolean inferred)

undeclare

void undeclare(Var var)

Description copied from class: Scope

Undeclares a variable, to be used when the compiler optimizes out a variable and removes it from the scope.

Overrides:

undeclare in class Scope

getSlot

public TypedVar getSlot(java.lang.String name)

Description copied from interface: StaticScope

Returns any defined slot within this scope for this name. This call continues searching through parent scopes if a slot with this name is not found in the current scope.

Specified by:

getSlot in interface StaticTypedScope<JSType>

Specified by:

getSlot in interface StaticScope

Overrides:

getSlot in class Scope

Parameters:

name - The name of the variable slot to look up.

Returns:

The defined slot for the variable, or null if no definition exists.

getOwnSlot

public TypedVar getOwnSlot(java.lang.String name)

Description copied from interface: StaticScope

Like getSlot but does not recurse into parent scopes.

Specified by:

getOwnSlot in interface StaticTypedScope<JSType>

Specified by:

getOwnSlot in interface StaticScope

Overrides:

getOwnSlot in class Scope

getVar

public TypedVar getVar(java.lang.String name)

Description copied from class: Scope

Returns the variable, may be null

Overrides:

getVar in class Scope

getArgumentsVar

public Var getArgumentsVar()

Description copied from class: Scope

Get a unique VAR object to represents "arguments" within this scope

Overrides:

getArgumentsVar in class Scope

isDeclared

public boolean isDeclared(java.lang.String name,
                          boolean recurse)

Description copied from class: Scope

Returns true if a variable is declared.

Overrides:

isDeclared in class Scope

getVars

public java.util.Iterator<TypedVar> getVars()

Description copied from class: Scope

Return an iterator over all of the variables declared in this scope.

Overrides:

getVars in class Scope

getVarIterable

java.lang.Iterable<Var> getVarIterable()

Description copied from class: Scope

Return an iterable over all of the variables declared in this scope (except the special 'arguments' variable).

Overrides:

getVarIterable in class Scope

getAllSymbols

public java.lang.Iterable<TypedVar> getAllSymbols()

Overrides:

getAllSymbols in class Scope

getVarCount

public int getVarCount()

Description copied from class: Scope

Returns number of variables in this scope (excluding the special 'arguments' variable)

Overrides:

getVarCount in class Scope

isGlobal

public boolean isGlobal()

Description copied from class: Scope

Returns whether this is the global scope.

Overrides:

isGlobal in class Scope

isLocal

public boolean isLocal()

Description copied from class: Scope

Returns whether this is a local scope (i.e. not the global scope).

Overrides:

isLocal in class Scope

getDeclarativelyUnboundVarsWithoutTypes

public java.util.Iterator<TypedVar> getDeclarativelyUnboundVarsWithoutTypes()

resolveTypes

void resolveTypes()

Resolve all type references. Only used on typed scopes.

setTypeResolver

void setTypeResolver(TypedScope.TypeResolver resolver)

isBlockScope

public boolean isBlockScope()

Overrides:

isBlockScope in class Scope

isFunctionBlockScope

public boolean isFunctionBlockScope()

Overrides:

isFunctionBlockScope in class Scope

getClosestHoistScope

public Scope getClosestHoistScope()

Description copied from class: Scope

If a var were declared in this scope, return the scope it would be hoisted to. For function scopes, we return back the scope itself, since even though there is no way to declare a var inside function parameters, it would make even less sense to say that such declarations would be "hoisted" somewhere else.

Overrides:

getClosestHoistScope in class Scope