AbstractScope (Closure Compiler v20190528 API)

java.lang.Object
- com.google.javascript.jscomp.AbstractScope<S,V>

All Implemented Interfaces:

StaticScope, java.io.Serializable

Direct Known Subclasses:

Scope, TypedScope
```
public abstract class AbstractScope<S extends AbstractScope<S,V>,V extends AbstractVar<S,V>>
extends java.lang.Object
implements StaticScope, java.io.Serializable
```
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.
ES 2015 introduces new scoping rules, which adds some complexity to this class. In particular, scopes fall into two mutually exclusive categories: block and container. Block scopes are all scopes whose roots are blocks, as well as any control structures whose optional blocks are omitted. These scopes did not exist at all prior to ES 2015. Container scopes comprise function scopes, global scopes, and module scopes, and (aside from modules, which didn't exist in ES5) corresponds to the ES5 scope rules. This corresponds roughly to one container scope per CFG root (but not exactly, due to SCRIPT-level CFGs).
All container scopes, plus the outermost block scope within a function (i.e. the function block scope) are considered hoist scopes. All functions thus have two hoist scopes: the function scope and the function block scope. Hoist scopes are relevant because "var" declarations are hoisted to the closest hoist scope, as opposed to "let" and "const" which always apply to the specific scope in which they occur.
Note that every function actually has two distinct hoist scopes: a container scope on the FUNCTION node, and a block-scope on the top-level BLOCK in the function (the "function block"). Local variables are declared on the function block, while parameters and optionally the function name (if it bleeds, i.e. from a named function expression) are declared on the container scope. This is required so that default parameter initializers can refer to names from outside the function that could possibly be shadowed in the function block. But these scopes are not fully independent of one another, since the language does not allow a top-level local variable to shadow a parameter name - so in some situations these scopes must be treated as a single scope.

See Also:

NodeTraversal, Serialized Form

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`java.lang.Iterable<V>`	`getAllAccessibleVariables()` Return an iterable over all of the variables accessible to this scope (i.e.
`java.lang.Iterable<V>`	`getAllSymbols()`
`V`	`getArgumentsVar()` Get a unique Var object to represent "arguments" within this scope.
`S`	`getClosestContainerScope()` Returns the closest container scope.
`S`	`getClosestHoistScope()` If a var were declared in this scope, return the scope it would be hoisted to.
`abstract int`	`getDepth()` The depth of the scope.
`S`	`getGlobalScope()` Walks up the tree to find the global scope.
`V`	`getOwnSlot(java.lang.String name)` Like `getSlot` but does not recurse into parent scopes.
`abstract S`	`getParent()` Returns the parent scope, or null if this is the global scope.
`S`	`getParentScope()` Returns the scope enclosing this one or null if none.
`Node`	`getRootNode()` Gets the container node of the scope.
`V`	`getSlot(java.lang.String name)` Returns any defined slot within this scope for this name.
`V`	`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)
`java.lang.Iterable<V>`	`getVarIterable()` Return an iterable over all of the variables declared in this scope (except the special 'arguments' variable).
`protected boolean`	`hasOwnImplicitSlot(com.google.javascript.jscomp.AbstractScope.ImplicitVar name)` Returns true iff this scope implies a slot with the given name.
`boolean`	`hasOwnSlot(java.lang.String name)` Returns true if a variable is declared in this scope, with no recursion.
`boolean`	`hasSlot(java.lang.String name)` Returns true if a variable is declared in this or any parent scope.
`boolean`	`isBlockScope()`
`boolean`	`isCatchScope()`
`boolean`	`isFunctionBlockScope()`
`boolean`	`isFunctionScope()`
`boolean`	`isGlobal()` Returns whether this is the global scope.
`boolean`	`isLocal()` Returns whether this is a local scope (i.e.
`boolean`	`isModuleScope()`
`java.lang.String`	`toString()`
`TypedScope`	`typed()`
`Scope`	`untyped()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Method Detail
  - getDepth
```
public abstract int getDepth()
```
    The depth of the scope. The global scope has depth 0.
  - getParent
```
public abstract S getParent()
```
    Returns the parent scope, or null if this is the global scope.
  - toString
```
public final java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object
  - untyped
```
public Scope untyped()
```
  - typed
```
public TypedScope typed()
```
  - 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
  - getGlobalScope
```
public final S getGlobalScope()
```
    Walks up the tree to find the global scope.
  - getParentScope
```
public final S getParentScope()
```
    Description copied from interface: StaticScope
    
    Returns the scope enclosing this one or null if none.
    
    Specified by:
    
    getParentScope in interface StaticScope
  - hasOwnImplicitSlot
```
protected boolean hasOwnImplicitSlot(@Nullable
                                     com.google.javascript.jscomp.AbstractScope.ImplicitVar name)
```
    Returns true iff this scope implies a slot with the given name.
  - hasOwnSlot
```
public final boolean hasOwnSlot(java.lang.String name)
```
    Returns true if a variable is declared in this scope, with no recursion.
  - hasSlot
```
public final boolean hasSlot(java.lang.String name)
```
    Returns true if a variable is declared in this or any parent scope.
  - getOwnSlot
```
public final V getOwnSlot(java.lang.String name)
```
    Description copied from interface: StaticScope
    
    Like getSlot but does not recurse into parent scopes.
    
    Specified by:
    
    getOwnSlot in interface StaticScope
  - getSlot
```
public final V 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 StaticScope
    
    Parameters:
    
    name - The name of the variable slot to look up.
    
    Returns:
    
    The defined slot for the variable, or null if no definition exists.
  - getVar
```
public V getVar(java.lang.String name)
```
    Returns the variable, may be null
    Non-final for TypedScope which needs to handle qualified names.
  - getArgumentsVar
```
public final V getArgumentsVar()
```
    Get a unique Var object to represent "arguments" within this scope.
    This explicitly excludes user declared variables that are names "arguments". It only returns special "arguments" variable that is inherent to a function.
  - getVarIterable
```
public java.lang.Iterable<V> getVarIterable()
```
    Return an iterable over all of the variables declared in this scope (except the special 'arguments' variable).
  - getAllAccessibleVariables
```
public final java.lang.Iterable<V> getAllAccessibleVariables()
```
    Return an iterable over all of the variables accessible to this scope (i.e. the variables in this scope and its parent scopes). Any variables declared in the local scope with the same name as a variable declared in a parent scope gain precedence - if let x exists in the block scope, a declaration let x from the parent scope would not be included because the parent scope's variable gets shadowed.
    The iterable contains variables from inner scopes before adding variables from outer parent scopes.
    We do not include the special 'arguments' variable.
  - getAllSymbols
```
public java.lang.Iterable<V> getAllSymbols()
```
  - getVarCount
```
public int getVarCount()
```
    Returns number of variables in this scope (excluding the special 'arguments' variable)
  - 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).
  - isBlockScope
```
public final boolean isBlockScope()
```
  - isFunctionBlockScope
```
public final boolean isFunctionBlockScope()
```
  - isFunctionScope
```
public final boolean isFunctionScope()
```
  - isModuleScope
```
public final boolean isModuleScope()
```
  - isCatchScope
```
public final boolean isCatchScope()
```
  - getClosestHoistScope
```
public final S getClosestHoistScope()
```
    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.
  - getClosestContainerScope
```
public final S getClosestContainerScope()
```
    Returns the closest container scope. This is equivalent to what the current scope would have been for non-ES6 scope creators, and is thus useful for migrating code to use block scopes.

Class AbstractScope<S extends AbstractScope<S,V>,V extends AbstractVar<S,V>>

Method Summary

Methods inherited from class java.lang.Object

Method Detail

getDepth

getParent

toString

untyped

typed

getRootNode

getGlobalScope

getParentScope

hasOwnImplicitSlot

hasOwnSlot

hasSlot

getOwnSlot

getSlot

getVar

getArgumentsVar

getVarIterable

getAllAccessibleVariables

getAllSymbols

getVarCount

isGlobal

isLocal

isBlockScope

isFunctionBlockScope

isFunctionScope

isModuleScope

isCatchScope

getClosestHoistScope

getClosestContainerScope