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package scala.reflect
package base
trait Symbols { self: Universe =>
// [Eugene++ to Martin] why is Symbol >: Null, whereas all other symbol types are not nullable?
// same question goes for Types
/** The abstract type of symbols representing declarations */
type Symbol >: Null <: SymbolBase
/** A tag that preserves the identity of the `Symbol` abstract type from erasure.
* Can be used for pattern matching, instance tests, serialization and likes.
*/
implicit val SymbolTag: ClassTag[Symbol]
/** The abstract type of type symbols representing type, class, and trait declarations,
* as well as type parameters
*/
type TypeSymbol >: Null <: Symbol with TypeSymbolBase
/** A tag that preserves the identity of the `TypeSymbol` abstract type from erasure.
* Can be used for pattern matching, instance tests, serialization and likes.
*/
implicit val TypeSymbolTag: ClassTag[TypeSymbol]
/** The abstract type of term symbols representing val, var, def, and object declarations as
* well as packages and value parameters.
*/
type TermSymbol >: Null <: Symbol with TermSymbolBase
/** A tag that preserves the identity of the `TermSymbol` abstract type from erasure.
* Can be used for pattern matching, instance tests, serialization and likes.
*/
implicit val TermSymbolTag: ClassTag[TermSymbol]
/** The abstract type of method symbols representing def declarations */
type MethodSymbol >: Null <: TermSymbol with MethodSymbolBase
/** A tag that preserves the identity of the `MethodSymbol` abstract type from erasure.
* Can be used for pattern matching, instance tests, serialization and likes.
*/
implicit val MethodSymbolTag: ClassTag[MethodSymbol]
/** The abstract type of module symbols representing object declarations */
type ModuleSymbol >: Null <: TermSymbol with ModuleSymbolBase
/** A tag that preserves the identity of the `ModuleSymbol` abstract type from erasure.
* Can be used for pattern matching, instance tests, serialization and likes.
*/
implicit val ModuleSymbolTag: ClassTag[ModuleSymbol]
/** The abstract type of class symbols representing class and trait definitions */
type ClassSymbol >: Null <: TypeSymbol with ClassSymbolBase
/** A tag that preserves the identity of the `ClassSymbol` abstract type from erasure.
* Can be used for pattern matching, instance tests, serialization and likes.
*/
implicit val ClassSymbolTag: ClassTag[ClassSymbol]
/** The abstract type of free terms introduced by reification */
type FreeTermSymbol >: Null <: TermSymbol with FreeTermSymbolBase
/** A tag that preserves the identity of the `FreeTermSymbol` abstract type from erasure.
* Can be used for pattern matching, instance tests, serialization and likes.
*/
implicit val FreeTermSymbolTag: ClassTag[FreeTermSymbol]
/** The abstract type of free types introduced by reification */
type FreeTypeSymbol >: Null <: TypeSymbol with FreeTypeSymbolBase
/** A tag that preserves the identity of the `FreeTypeSymbol` abstract type from erasure.
* Can be used for pattern matching, instance tests, serialization and likes.
*/
implicit val FreeTypeSymbolTag: ClassTag[FreeTypeSymbol]
/** A special "missing" symbol */
val NoSymbol: Symbol
/** The base API that all symbols support */
trait SymbolBase { this: Symbol =>
/** An id number which is unique for all symbols in this universe */
// [Eugene++ to Martin] do we leave this here?
def id: Int
/** The owner of this symbol. This is the symbol
* that directly contains the current symbol's definition.
* The `NoSymbol` symbol does not have an owner, and calling this method
* on one causes an internal error.
* The owner of the Scala root class [[scala.reflect.api.mirror.RootClass]]
* and the Scala root object [[scala.reflect.api.mirror.RootPackage]] is `NoSymbol`.
* Every other symbol has a chain of owners that ends in
* [[scala.reflect.api.mirror.RootClass]].
*/
def owner: Symbol
/** The type of the symbol name.
* Can be either `TermName` or `TypeName` depending on whether this is a `TermSymbol` or a `TypeSymbol`.
*
* Type name namespaces do not intersect with term name namespaces.
* This fact is reflected in different types for names of `TermSymbol` and `TypeSymbol`.
*/
type NameType >: Null <: Name
/** The name of the symbol as a member of the `Name` type.
*/
def name: Name
/** The encoded full path name of this symbol, where outer names and inner names
* are separated by periods.
*/
def fullName: String
/** If this symbol is a class, this symbol; otherwise the next enclosing
* class, or `NoSymbol` if none exists.
*/
def enclosingClass: Symbol =
if (isClass || this == NoSymbol) this else owner.enclosingClass
/** If this symbol is a method, this symbol; otherwise the next enclosing
* method, or `NoSymbol` if none exists.
*/
def enclosingMethod: Symbol =
if (isMethod || this == NoSymbol) this else owner.enclosingMethod
/** Does this symbol represent the definition of a type?
* Note that every symbol is either a term or a type.
* So for every symbol `sym`, either `sym.isTerm` is true
* or `sym.isType` is true.
*/
def isType: Boolean = false
/** This symbol cast to a TypeSymbol.
* Returns ClassCastException if `isType` is false.
*/
def asTypeSymbol: TypeSymbol = throw new ClassCastException(toString)
/** Does this symbol represent the definition of a term?
* Note that every symbol is either a term or a term.
* So for every symbol `sym`, either `sym.isTerm` is true
* or `sym.isTerm` is true.
*/
def isTerm: Boolean = false
/** This symbol cast to a TermSymbol.
* Returns ClassCastException if `isTerm` is false.
*/
def asTermSymbol: TermSymbol = throw new ClassCastException(toString)
/** Does this symbol represent the definition of a method?
* If yes, `isTerm` is also guaranteed to be true.
*/
def isMethod: Boolean = false
/** This symbol cast to a MethodSymbol.
* Returns ClassCastException if `isMethod` is false.
*/
def asMethodSymbol: MethodSymbol = throw new ClassCastException(toString)
/** Does this symbol represent the definition of a module (i.e. it
* results from an object definition?).
* If yes, `isTerm` is also guaranteed to be true.
*/
def isModule: Boolean = false
/** This symbol cast to a ModuleSymbol defined by an object definition.
* Returns ClassCastException if `isModule` is false.
*/
def asModuleSymbol: ModuleSymbol = throw new ClassCastException(toString)
/** Does this symbol represent the definition of a class or trait?
* If yes, `isType` is also guaranteed to be true.
*/
def isClass: Boolean = false
/** This symbol cast to a ClassSymbol representing a class or trait.
* Returns ClassCastException if `isClass` is false.
*/
def asClassSymbol: ClassSymbol = throw new ClassCastException(toString)
/** Does this symbol represent a free term captured by reification?
* If yes, `isTerm` is also guaranteed to be true.
*/
def isFreeTerm: Boolean = false
/** This symbol cast to a free term symbol.
* Returns ClassCastException if `isFreeTerm` is false.
*/
def asFreeTermSymbol: FreeTermSymbol = throw new ClassCastException(toString)
/** Does this symbol represent a free type captured by reification?
* If yes, `isType` is also guaranteed to be true.
*/
def isFreeType: Boolean = false
/** This symbol cast to a free type symbol.
* Returns ClassCastException if `isFreeType` is false.
*/
def asFreeTypeSymbol: FreeTypeSymbol = throw new ClassCastException(toString)
def newTermSymbol(name: TermName, pos: Position = NoPosition, flags: FlagSet = NoFlags): TermSymbol
def newModuleAndClassSymbol(name: Name, pos: Position = NoPosition, flags: FlagSet = NoFlags): (ModuleSymbol, ClassSymbol)
def newMethodSymbol(name: TermName, pos: Position = NoPosition, flags: FlagSet = NoFlags): MethodSymbol
def newTypeSymbol(name: TypeName, pos: Position = NoPosition, flags: FlagSet = NoFlags): TypeSymbol
def newClassSymbol(name: TypeName, pos: Position = NoPosition, flags: FlagSet = NoFlags): ClassSymbol
}
/** The base API that all type symbols support */
trait TypeSymbolBase extends SymbolBase { this: TypeSymbol =>
/** Type symbols have their names of type `TypeName`.
*/
final type NameType = TypeName
/** The type constructor corresponding to this type symbol.
* This is different from `asType` in that type parameters
* are part of results of `asType`, but not of `asTypeConstructor`.
*
* Example: Given a class declaration `class C[T] { ... } `, that generates a symbol
* `C`. Then `C.asType` is the type `C[T]`, but `C.asTypeConstructor` is `C`.
*/
def asTypeConstructor: Type
override def isType = true
override def asTypeSymbol = this
}
/** The base API that all term symbols support */
trait TermSymbolBase extends SymbolBase { this: TermSymbol =>
/** Term symbols have their names of type `TermName`.
*/
final type NameType = TermName
final override def isTerm = true
final override def asTermSymbol = this
}
/** The base API that all method symbols support */
trait MethodSymbolBase extends TermSymbolBase { this: MethodSymbol =>
final override def isMethod = true
final override def asMethodSymbol = this
}
/** The base API that all module symbols support */
trait ModuleSymbolBase extends TermSymbolBase { this: ModuleSymbol =>
/** The class implicitly associated with the object definition.
*/
def moduleClass: Symbol // needed for tree traversals
// [Eugene++] when this becomes `moduleClass: ClassSymbol`, it will be the happiest day in my life
final override def isModule = true
final override def asModuleSymbol = this
}
/** The base API that all class symbols support */
trait ClassSymbolBase extends TypeSymbolBase { this: ClassSymbol =>
final override def isClass = true
final override def asClassSymbol = this
}
/** The base API that all free type symbols support */
trait FreeTypeSymbolBase extends TypeSymbolBase { this: FreeTypeSymbol =>
final override def isFreeType = true
final override def asFreeTypeSymbol = this
}
/** The base API that all free term symbols support */
trait FreeTermSymbolBase extends TermSymbolBase { this: FreeTermSymbol =>
final override def isFreeTerm = true
final override def asFreeTermSymbol = this
}
}
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