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com.google.javascript.jscomp
Class Scope

java.lang.Object
  extended by com.google.javascript.jscomp.Scope
All Implemented Interfaces:
StaticScope<JSType>, StaticSymbolTable<Scope.Var,Scope.Var>
public class Scope
extends Object
implements StaticScope<JSType>, StaticSymbolTable<Scope.Var,Scope.Var>

Scope contains information about a variable scope in javascript. Scopes can be nested, a scope points back to its parent scope. A Scope contains information about variables defined in that scope.

A Scope 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, DataFlowAnalysis

Nested Class Summary
static class Scope.Arguments
          A special subclass of Var used to distinguish "arguments" in the current scope.
static class Scope.Var
          Stores info about a variable
 
Method Summary
 Iterable<Scope.Var> getAllSymbols()
          Returns all variables in this symbol table.
 Scope.Var getArgumentsVar()
          Get a unique VAR object to represents "arguments" within this scope
 Iterator<Scope.Var> getDeclarativelyUnboundVarsWithoutTypes()
          Gets all variables declared with "var" but without declared types attached.
 StaticSlot<JSType> getOwnSlot(String name)
          Like getSlot but does not recurse into parent scopes.
 Scope getParent()
           
 StaticScope<JSType> getParentScope()
          Returns the scope enclosing this one or null if none.
 Iterable<Scope.Var> getReferences(Scope.Var var)
          Returns the references that point to the given symbol.
 Node getRootNode()
          Gets the container node of the scope.
 StaticScope<JSType> getScope(Scope.Var var)
          Returns the scope for a given symbol.
 StaticSlot<JSType> getSlot(String name)
          Returns any defined slot within this scope for this name.
 ObjectType getTypeOfThis()
          Gets the type of this in the current scope.
 Scope.Var getVar(String name)
          Returns the variable, may be null
 int getVarCount()
          Returns number of variables in this scope
 Iterator<Scope.Var> getVars()
          Return an iterator over all of the variables declared in this scope.
 boolean isDeclared(String name, boolean recurse)
          Returns true if a variable is declared.
 boolean isGlobal()
          Returns whether this is the global scope.
 boolean isLocal()
          Returns whether this is a local scope (i.e.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Method Detail

getRootNode

public Node getRootNode()
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<JSType>

getParent

public Scope getParent()

getParentScope

public StaticScope<JSType> getParentScope()
Description copied from interface: StaticScope
Returns the scope enclosing this one or null if none.

Specified by:
getParentScope in interface StaticScope<JSType>

getTypeOfThis

public ObjectType getTypeOfThis()
Gets the type of this in the current scope.

Specified by:
getTypeOfThis in interface StaticScope<JSType>

getSlot

public StaticSlot<JSType> getSlot(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 StaticScope<JSType>
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 StaticSlot<JSType> getOwnSlot(String name)
Description copied from interface: StaticScope
Like getSlot but does not recurse into parent scopes.

Specified by:
getOwnSlot in interface StaticScope<JSType>

getVar

public Scope.Var getVar(String name)
Returns the variable, may be null

getArgumentsVar

public Scope.Var getArgumentsVar()
Get a unique VAR object to represents "arguments" within this scope

isDeclared

public boolean isDeclared(String name,
                          boolean recurse)
Returns true if a variable is declared.

getVars

public Iterator<Scope.Var> getVars()
Return an iterator over all of the variables declared in this scope.

getReferences

public Iterable<Scope.Var> getReferences(Scope.Var var)
Description copied from interface: StaticSymbolTable
Returns the references that point to the given symbol.

Specified by:
getReferences in interface StaticSymbolTable<Scope.Var,Scope.Var>

getScope

public StaticScope<JSType> getScope(Scope.Var var)
Description copied from interface: StaticSymbolTable
Returns the scope for a given symbol.

Specified by:
getScope in interface StaticSymbolTable<Scope.Var,Scope.Var>

getAllSymbols

public Iterable<Scope.Var> getAllSymbols()
Description copied from interface: StaticSymbolTable
Returns all variables in this symbol table.

Specified by:
getAllSymbols in interface StaticSymbolTable<Scope.Var,Scope.Var>

getVarCount

public int getVarCount()
Returns number of variables in this scope

isGlobal

public boolean isGlobal()
Returns whether this is the global scope.

isLocal

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

getDeclarativelyUnboundVarsWithoutTypes

public Iterator<Scope.Var> getDeclarativelyUnboundVarsWithoutTypes()
Gets all variables declared with "var" but without declared types attached.

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