trait Typers extends AnyRef
EXPERIMENTAL
A slice of the Scala macros context that partially exposes the type checker to macro writers.
- Self Type
- blackbox.Context
- Source
- Typers.scala
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Type Members
-
type
TypecheckException = macros.TypecheckException
- See also
scala.reflect.macros.TypecheckException
-
abstract
type
TypecheckMode
Represents mode of operations of the typechecker underlying
c.typecheck
calls.Represents mode of operations of the typechecker underlying
c.typecheck
calls. Is necessary since the shape of the typechecked tree alone is not enough to guess how it should be typechecked. Can be EXPRmode (typecheck as a term), TYPEmode (typecheck as a type) or PATTERNmode (typecheck as a pattern).
Abstract Value Members
-
abstract
val
PATTERNmode: blackbox.Context.TypecheckMode
Indicates that an argument to
c.typecheck
should be typechecked as a pattern. -
abstract
val
TERMmode: blackbox.Context.TypecheckMode
Indicates that an argument to
c.typecheck
should be typechecked as a term.Indicates that an argument to
c.typecheck
should be typechecked as a term. This is the default typechecking mode in Scala 2.11 and the only one supported in Scala 2.10. -
abstract
val
TYPEmode: blackbox.Context.TypecheckMode
Indicates that an argument to
c.typecheck
should be typechecked as a type. -
abstract
def
inferImplicitValue(pt: blackbox.Context.Type, silent: Boolean = true, withMacrosDisabled: Boolean = false, pos: blackbox.Context.Position = enclosingPosition): blackbox.Context.Tree
Infers an implicit value of the expected type
pt
in the macro callsite context.Infers an implicit value of the expected type
pt
in the macro callsite context. Optionalpos
parameter provides a position that will be associated with the implicit search.If
silent
is false,TypecheckException
will be thrown in case of an inference error. Ifsilent
is true, the typecheck is silent and will returnEmptyTree
if an error occurs. Such errors don't vanish and can be inspected by turning on -Xlog-implicits. Unlike intypecheck
,silent
is true by default.- Exceptions thrown
-
abstract
def
inferImplicitView(tree: blackbox.Context.Tree, from: blackbox.Context.Type, to: blackbox.Context.Type, silent: Boolean = true, withMacrosDisabled: Boolean = false, pos: blackbox.Context.Position = enclosingPosition): blackbox.Context.Tree
Infers an implicit view from the provided tree
tree
of the typefrom
to the typeto
in the macro callsite context.Infers an implicit view from the provided tree
tree
of the typefrom
to the typeto
in the macro callsite context. Optionalpos
parameter provides a position that will be associated with the implicit search.If
silent
is false,TypecheckException
will be thrown in case of an inference error. Ifsilent
is true, the typecheck is silent and will returnEmptyTree
if an error occurs. Such errors don't vanish and can be inspected by turning on -Xlog-implicits. Unlike intypecheck
,silent
is true by default.- Exceptions thrown
-
abstract
def
openMacros: List[blackbox.Context]
Contexts that represent macros in-flight, including the current one.
Contexts that represent macros in-flight, including the current one. Very much like a stack trace, but for macros only. Can be useful for interoperating with other macros and for imposing compiler-friendly limits on macro expansion.
Is also priceless for emitting sane error messages for macros that are called by other macros on synthetic (i.e. position-less) trees. In that dire case navigate the
openMacros
stack, and it will most likely contain at least one macro with a position-ful macro application. SeeenclosingPosition
for a default implementation of this logic.Unlike
enclosingMacros
, this is a def, which means that it gets recalculated on every invocation, so it might change depending on what is going on during macro expansion. -
abstract
def
typecheck(tree: blackbox.Context.Tree, mode: blackbox.Context.TypecheckMode = TERMmode, pt: blackbox.Context.Type = universe.WildcardType, silent: Boolean = false, withImplicitViewsDisabled: Boolean = false, withMacrosDisabled: Boolean = false): blackbox.Context.Tree
Typechecks the provided tree against the expected type
pt
in the macro callsite context under typechecking mode specified inmode
with EXPRmode being default.Typechecks the provided tree against the expected type
pt
in the macro callsite context under typechecking mode specified inmode
with EXPRmode being default. This populates symbols and types of the tree and possibly transforms it to reflect certain desugarings.If
silent
is false,TypecheckException
will be thrown in case of a typecheck error. Ifsilent
is true, the typecheck is silent and will returnEmptyTree
if an error occurs. Such errors don't vanish and can be inspected by turning on -Ymacro-debug-verbose. Unlike ininferImplicitValue
andinferImplicitView
,silent
is false by default.Typechecking can be steered with the following optional parameters:
withImplicitViewsDisabled
recursively prohibits implicit views (though, implicit vals will still be looked up and filled in), default value is falsewithMacrosDisabled
recursively prohibits macro expansions and macro-based implicits, default value is false- Exceptions thrown
-
abstract
def
untypecheck(tree: blackbox.Context.Tree): blackbox.Context.Tree
In the current implementation of Scala's reflection API, untyped trees (also known as parser trees or unattributed trees) are observationally different from typed trees (also known as typer trees, typechecked trees or attributed trees),
In the current implementation of Scala's reflection API, untyped trees (also known as parser trees or unattributed trees) are observationally different from typed trees (also known as typer trees, typechecked trees or attributed trees),
Usually, if some compiler API takes a tree, then both untyped and typed trees will do. However in some cases, only untyped or only typed trees are appropriate. For example, eval only accepts untyped trees and one can only splice typed trees inside typed trees. Therefore in the current reflection API, there is a need in functions that go back and forth between untyped and typed trees. For this we have typecheck and
untypecheck
.Note that
untypecheck
is currently afflicted by https://issues.scala-lang.org/browse/SI-5464, which makes it sometimes corrupt trees so that they don't make sense anymore. Unfortunately, there's no workaround for that. We plan to fix this issue soon, but for now please keep it in mind. -
abstract
def
resetLocalAttrs(tree: blackbox.Context.Tree): blackbox.Context.Tree
Recursively resets locally defined symbols and types in a given tree.
Recursively resets locally defined symbols and types in a given tree. WARNING: Don't use this API, go for untypecheck instead.
- Annotations
- @deprecated
- Deprecated
(Since version 2.11.0) use
c.untypecheck
instead
Concrete Value Members
-
final
def
!=(arg0: Any): Boolean
Test two objects for inequality.
Test two objects for inequality.
- returns
true
if !(this == that), false otherwise.
- Definition Classes
- AnyRef → Any
-
final
def
##(): Int
Equivalent to
x.hashCode
except for boxed numeric types andnull
.Equivalent to
x.hashCode
except for boxed numeric types andnull
. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. Fornull
returns a hashcode wherenull.hashCode
throws aNullPointerException
.- returns
a hash value consistent with ==
- Definition Classes
- AnyRef → Any
- def +(other: String): String
- def ->[B](y: B): (Typers, B)
-
final
def
==(arg0: Any): Boolean
The expression
x == that
is equivalent toif (x eq null) that eq null else x.equals(that)
.The expression
x == that
is equivalent toif (x eq null) that eq null else x.equals(that)
.- returns
true
if the receiver object is equivalent to the argument;false
otherwise.
- Definition Classes
- AnyRef → Any
-
val
TypecheckException: macros.TypecheckException.type
- See also
scala.reflect.macros.TypecheckException
-
final
def
asInstanceOf[T0]: T0
Cast the receiver object to be of type
T0
.Cast the receiver object to be of type
T0
.Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression
1.asInstanceOf[String]
will throw aClassCastException
at runtime, while the expressionList(1).asInstanceOf[List[String]]
will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.- returns
the receiver object.
- Definition Classes
- Any
- Exceptions thrown
ClassCastException
if the receiver object is not an instance of the erasure of typeT0
.
-
def
clone(): AnyRef
Create a copy of the receiver object.
Create a copy of the receiver object.
The default implementation of the
clone
method is platform dependent.- returns
a copy of the receiver object.
- Attributes
- protected[java.lang]
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
- Note
not specified by SLS as a member of AnyRef
- def ensuring(cond: (Typers) ⇒ Boolean, msg: ⇒ Any): Typers
- def ensuring(cond: (Typers) ⇒ Boolean): Typers
- def ensuring(cond: Boolean, msg: ⇒ Any): Typers
- def ensuring(cond: Boolean): Typers
-
final
def
eq(arg0: AnyRef): Boolean
Tests whether the argument (
that
) is a reference to the receiver object (this
).Tests whether the argument (
that
) is a reference to the receiver object (this
).The
eq
method implements an equivalence relation on non-null instances ofAnyRef
, and has three additional properties:- It is consistent: for any non-null instances
x
andy
of typeAnyRef
, multiple invocations ofx.eq(y)
consistently returnstrue
or consistently returnsfalse
. - For any non-null instance
x
of typeAnyRef
,x.eq(null)
andnull.eq(x)
returnsfalse
. null.eq(null)
returnstrue
.
When overriding the
equals
orhashCode
methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2
), they should be equal to each other (o1 == o2
) and they should hash to the same value (o1.hashCode == o2.hashCode
).- returns
true
if the argument is a reference to the receiver object;false
otherwise.
- Definition Classes
- AnyRef
- It is consistent: for any non-null instances
-
def
equals(arg0: Any): Boolean
The equality method for reference types.
-
def
finalize(): Unit
Called by the garbage collector on the receiver object when there are no more references to the object.
Called by the garbage collector on the receiver object when there are no more references to the object.
The details of when and if the
finalize
method is invoked, as well as the interaction betweenfinalize
and non-local returns and exceptions, are all platform dependent.- Attributes
- protected[java.lang]
- Definition Classes
- AnyRef
- Annotations
- @throws( classOf[java.lang.Throwable] )
- Note
not specified by SLS as a member of AnyRef
- def formatted(fmtstr: String): String
-
final
def
getClass(): Class[_]
Returns the runtime class representation of the object.
Returns the runtime class representation of the object.
- returns
a class object corresponding to the runtime type of the receiver.
- Definition Classes
- AnyRef → Any
-
def
hashCode(): Int
The hashCode method for reference types.
-
final
def
isInstanceOf[T0]: Boolean
Test whether the dynamic type of the receiver object is
T0
.Test whether the dynamic type of the receiver object is
T0
.Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression
1.isInstanceOf[String]
will returnfalse
, while the expressionList(1).isInstanceOf[List[String]]
will returntrue
. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.- returns
true
if the receiver object is an instance of erasure of typeT0
;false
otherwise.
- Definition Classes
- Any
-
final
def
ne(arg0: AnyRef): Boolean
Equivalent to
!(this eq that)
.Equivalent to
!(this eq that)
.- returns
true
if the argument is not a reference to the receiver object;false
otherwise.
- Definition Classes
- AnyRef
-
final
def
notify(): Unit
Wakes up a single thread that is waiting on the receiver object's monitor.
Wakes up a single thread that is waiting on the receiver object's monitor.
- Definition Classes
- AnyRef
- Note
not specified by SLS as a member of AnyRef
-
final
def
notifyAll(): Unit
Wakes up all threads that are waiting on the receiver object's monitor.
Wakes up all threads that are waiting on the receiver object's monitor.
- Definition Classes
- AnyRef
- Note
not specified by SLS as a member of AnyRef
-
final
def
synchronized[T0](arg0: ⇒ T0): T0
- Definition Classes
- AnyRef
-
def
toString(): String
Creates a String representation of this object.
Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.
- returns
a String representation of the object.
- Definition Classes
- AnyRef → Any
-
final
def
wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
-
final
def
wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
-
final
def
wait(arg0: Long): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
- def →[B](y: B): (Typers, B)
Deprecated Value Members
-
def
typeCheck(tree: blackbox.Context.Tree, pt: blackbox.Context.Type = universe.WildcardType, silent: Boolean = false, withImplicitViewsDisabled: Boolean = false, withMacrosDisabled: Boolean = false): blackbox.Context.Tree
- Annotations
- @deprecated
- Deprecated
(Since version 2.11.0) use
c.typecheck
instead- See also
Typers.typecheck