com.google.javascript.jscomp.type

Interface FlowScope

All Superinterfaces:

LatticeElement, StaticScope<JSType>

public interface FlowScope
extends StaticScope<JSType>, LatticeElement

A symbol table for inferring types during data flow analysis. Each flow scope represents the types of all variables in the scope at a particular point in the flow analysis.

Author:

nicksantos@google.com (Nick Santos)

Method Summary

Methods

Modifier and Type	Method and Description
void	completeScope(StaticScope<JSType> scope) Look through the given scope, and try to find slots where it doesn't have enough type information.
FlowScope	createChildFlowScope() Creates a child of this flow scope, to represent an instruction directly following this one.
StaticSlot<JSType>	findUniqueRefinedSlot(FlowScope blindScope) Tries to find a unique refined variable in the refined scope, up to the the blind scope.
void	inferQualifiedSlot(Node node, String symbol, JSType bottomType, JSType inferredType) Infer the type of a qualified name.
void	inferSlotType(String symbol, JSType type) Defines the type of a symbol at this point in the flow.
FlowScope	optimize() Optimize this scope and return a new FlowScope with faster lookup.

Methods inherited from interface com.google.javascript.rhino.jstype.StaticScope

getOwnSlot, getParentScope, getRootNode, getSlot, getTypeOfThis

Method Detail

createChildFlowScope

FlowScope createChildFlowScope()

Creates a child of this flow scope, to represent an instruction directly following this one.

inferSlotType

void inferSlotType(String symbol,
                 JSType type)

Defines the type of a symbol at this point in the flow.

Throws:

IllegalArgumentException - If no slot for this symbol exists.

inferQualifiedSlot

void inferQualifiedSlot(Node node,
                      String symbol,
                      JSType bottomType,
                      JSType inferredType)

Infer the type of a qualified name. When traversing the control flow of a function, simple names are declared at the bottom of the flow lattice. But there are far too many qualified names to be able to do this and be performant. So the bottoms of qualified names are declared lazily. Therefore, when inferring a qualified slot, we need both the "bottom" type of the slot when we enter the scope, and the current type being inferred.

optimize

FlowScope optimize()

Optimize this scope and return a new FlowScope with faster lookup.

findUniqueRefinedSlot

StaticSlot<JSType> findUniqueRefinedSlot(FlowScope blindScope)

Tries to find a unique refined variable in the refined scope, up to the the blind scope.

Parameters:

blindScope - The scope before the refinement, i.e. some parent of the this scope or itself.

Returns:

The unique refined variable if found or null.

completeScope

void completeScope(StaticScope<JSType> scope)

Look through the given scope, and try to find slots where it doesn't have enough type information. Then fill in that type information with stuff that we've inferred in the local flow.