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.typecheckcalls.Represents mode of operations of the typechecker underlying
c.typecheckcalls. Is necessary since the shape of the typechecked tree alone is not enough to guess how it should be typechecked. Can be TERMmode (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.typecheckshould be typechecked as a pattern. - abstract val TERMmode: blackbox.Context.TypecheckMode
Indicates that an argument to
c.typecheckshould be typechecked as a term.Indicates that an argument to
c.typecheckshould 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.typecheckshould 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
ptin the macro callsite context.Infers an implicit value of the expected type
ptin the macro callsite context. Optionalposparameter provides a position that will be associated with the implicit search.If
silentis false,TypecheckExceptionwill be thrown in case of an inference error. Ifsilentis true, the typecheck is silent and will returnEmptyTreeif an error occurs. Such errors don't vanish and can be inspected by turning on -Vimplicits. Unlike intypecheck,silentis 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
treeof the typefromto the typetoin the macro callsite context.Infers an implicit view from the provided tree
treeof the typefromto the typetoin the macro callsite context. Optionalposparameter provides a position that will be associated with the implicit search.If
silentis false,TypecheckExceptionwill be thrown in case of an inference error. Ifsilentis true, the typecheck is silent and will returnEmptyTreeif an error occurs. Such errors don't vanish and can be inspected by turning on -Vimplicits. Unlike intypecheck,silentis 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
openMacrosstack, and it will most likely contain at least one macro with a position-ful macro application. SeeenclosingPositionfor 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
ptin the macro callsite context under typechecking mode specified inmodewith TERMmode being default.Typechecks the provided tree against the expected type
ptin the macro callsite context under typechecking mode specified inmodewith TERMmode being default. This populates symbols and types of the tree and possibly transforms it to reflect certain desugarings.If
silentis false,TypecheckExceptionwill be thrown in case of a typecheck error. Ifsilentis true, the typecheck is silent and will returnEmptyTreeif an error occurs. Such errors don't vanish and can be inspected by turning on -Ymacro-debug-verbose. Unlike ininferImplicitValueandinferImplicitView,silentis false by default.Typechecking can be steered with the following optional parameters:
withImplicitViewsDisabledrecursively prohibits implicit views (though, implicit vals will still be looked up and filled in), default value is falsewithMacrosDisabledrecursively 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, Evals.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
untypecheckis currently afflicted by https://github.com/scala/bug/issues/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.untypecheckinstead
Concrete Value Members
- final def !=(arg0: Any): Boolean
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- final def ##: Int
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- def +(other: String): String
- def ->[B](y: B): (Typers, B)
- final def ==(arg0: Any): Boolean
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- val TypecheckException: macros.TypecheckException.type
- See also
scala.reflect.macros.TypecheckException
- final def asInstanceOf[T0]: T0
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- def clone(): AnyRef
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- protected[lang]
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- @throws(classOf[java.lang.CloneNotSupportedException]) @native()
- 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
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- def equals(arg0: AnyRef): Boolean
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- def finalize(): Unit
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Deprecated Value Members
- def formatted(fmtstr: String): String
- Implicit
- This member is added by an implicit conversion from Typers toStringFormat[Typers] performed by method StringFormat in scala.Predef.
- Definition Classes
- StringFormat
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.12.16) Use
formatString.format(value)instead ofvalue.formatted(formatString), or use thef""string interpolator. In Java 15 and later,formattedresolves to the new method in String which has reversed parameters.
- 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.typecheckinstead- See also
Typers.typecheck
- def →[B](y: B): (Typers, B)
- Implicit
- This member is added by an implicit conversion from Typers toArrowAssoc[Typers] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use
->instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.