Package com.google.javascript.jscomp

Class SymbolTable

java.lang.Object
com.google.javascript.jscomp.SymbolTable
public final class SymbolTable extends Object
A symbol table for people that want to use Closure Compiler as an indexer.

Contains an index of all the symbols in the code within a compilation job. The API is designed for people who want to visit all the symbols, rather than people who want to lookup a specific symbol by a certain key.

We can use this to combine different types of symbol tables. For example, one class might have a StaticSymbolTable of all variable references, and another class might have a StaticSymbolTable of all type names in JSDoc comments. This class allows you to combine them into a unified index.

Most passes build their own "partial" symbol table that implements the same interface (StaticSymbolTable, StaticSlot, and friends). Individual compiler passes usually need more or less metadata about the certainty of symbol information. Building a complete symbol table with all the necessary metadata for all passes would be too slow. However, as long as these "partial" symbol tables implement the proper interfaces, we should be able to add them to this symbol table to make it more complete.

If clients want fast lookup, they should build their own wrapper around this symbol table that indexes symbols or references by the desired lookup key.

By design, when this symbol table creates symbols for types, it tries to mimic the symbol table you would get in an OO language. For example, the "type Foo" and "the constructor that creates objects of type Foo" are the same symbol. The types of "Foo.prototype" and "new Foo()" also have the same symbol. Although JSCompiler internally treats these as distinct symbols, we assume that most clients will not care about the distinction.

See Also:
  • For more information on how to write plugins for this symbol table.

  • Field Details

    • GLOBAL_THIS

      public static final String GLOBAL_THIS
      The name we use for the JavaScript built-in Global object. It's anonymous in JavaScript, so we have to give it an invalid identifier to avoid conflicts with user-defined property names.
      See Also:

  • Method Details

    • getReferences

      public Iterable<SymbolTable.Reference> getReferences(SymbolTable.Symbol symbol)

    • getReferenceList

      public com.google.common.collect.ImmutableList<SymbolTable.Reference> getReferenceList(SymbolTable.Symbol symbol)

    • getAllSymbols

      public com.google.common.collect.ImmutableList<SymbolTable.Symbol> getAllSymbols()

    • getAllSymbolsSorted

      public List<SymbolTable.Symbol> getAllSymbolsSorted()
      Get the symbols in their natural ordering. Always returns a mutable list.

    • getNaturalSymbolOrdering

      public com.google.common.collect.Ordering<SymbolTable.Symbol> getNaturalSymbolOrdering()
      Gets the 'natural' ordering of symbols.

      Right now, we only guarantee that symbols in the global scope will come before symbols in local scopes. After that, the order is deterministic but undefined.

    • getScope

      public SymbolTable.SymbolScope getScope(SymbolTable.Symbol slot)

    • getAllJSDocInfoNodes

      public Collection<Node> getAllJSDocInfoNodes()

    • getEnclosingScope

      public @Nullable SymbolTable.SymbolScope getEnclosingScope(Node n)
      Gets the scope that contains the given node. If n is a function name, we return the scope that contains the function, not the function itself.

    • getEnclosingFunctionScope

      public SymbolTable.SymbolScope getEnclosingFunctionScope(Node n)
      Gets the scope that contains the given node. If n is a function name, we return the scope that contains the function, not the function itself. The returned scope is either function or global scope.

    • getParameterInFunction

      public @Nullable SymbolTable.Symbol getParameterInFunction(SymbolTable.Symbol sym, String paramName)
      If sym is a function, try to find a Symbol for a parameter with the given name.

      Returns null if we couldn't find one.

      Notice that this just makes a best effort, and may not be able to find parameters for non-conventional function definitions. For example, we would not be able to find "y" in this code: var x = x() ? function(y) {} : function(y) {};

    • getSymbolForScope

      public SymbolTable.Symbol getSymbolForScope(SymbolTable.SymbolScope scope)
      All local scopes are associated with a function, and some functions are associated with a symbol. Returns the symbol associated with the given scope.

    • getAllSymbolsForTypeOf

      public Iterable<SymbolTable.Symbol> getAllSymbolsForTypeOf(SymbolTable.Symbol sym)
      Get all symbols associated with the type of the given symbol.

      For example, given a variable x declared as /* @type {Array|Date} / var x = f(); this will return the constructors for Array and Date.

    • getGlobalScope

      public SymbolTable.SymbolScope getGlobalScope()
      Returns the global scope.

    • getSymbolDeclaredBy

      public SymbolTable.Symbol getSymbolDeclaredBy(FunctionType fn)
      Gets the symbol for the given constructor or interface.

    • getSymbolDeclaredBy

      public SymbolTable.Symbol getSymbolDeclaredBy(EnumType enumType)
      Gets the symbol for the given enum.

    • getSymbolForInstancesOf

      public @Nullable SymbolTable.Symbol getSymbolForInstancesOf(SymbolTable.Symbol sym)
      Gets the symbol for the prototype if this is the symbol for a constructor or interface.

    • getSymbolForInstancesOf

      public SymbolTable.Symbol getSymbolForInstancesOf(FunctionType fn)
      Gets the symbol for the prototype of the given constructor or interface.

    • getAllSymbolsForType

      public List<SymbolTable.Symbol> getAllSymbolsForType(JSType type)
      Gets all symbols associated with the given type. For union types, this may be multiple symbols. For instance types, this will return the constructor of that instance.

    • toDebugStringTree

      public String toDebugStringTree()
      Methods returns debug representation of the SymbolTable. It starts with the global scope and all its symbols recursively going to children scopes and printing their symbols.

    • toDebugString

      public String toDebugString()

    • getAllScopes

      public Collection<SymbolTable.SymbolScope> getAllScopes()
      Gets all the scopes in this symbol table.

    • addAnonymousFunctions

      public void addAnonymousFunctions()
      Finds anonymous functions in local scopes, and gives them names and symbols. They will show up as local variables with names "function%0", "function%1", etc.