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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

  1. type TypecheckException = macros.TypecheckException

    See also

    scala.reflect.macros.TypecheckException

  2. 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 TERMmode (typecheck as a term), TYPEmode (typecheck as a type) or PATTERNmode (typecheck as a pattern).

Abstract Value Members

  1. abstract val PATTERNmode: blackbox.Context.TypecheckMode

    Indicates that an argument to c.typecheck should be typechecked as a pattern.

  2. 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.

  3. abstract val TYPEmode: blackbox.Context.TypecheckMode

    Indicates that an argument to c.typecheck should be typechecked as a type.

  4. 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. Optional pos 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. If silent is true, the typecheck is silent and will return EmptyTree if an error occurs. Such errors don't vanish and can be inspected by turning on -Xlog-implicits. Unlike in typecheck, silent is true by default.

    Exceptions thrown
  5. 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 type from to the type to in the macro callsite context.

    Infers an implicit view from the provided tree tree of the type from to the type to in the macro callsite context. Optional pos 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. If silent is true, the typecheck is silent and will return EmptyTree if an error occurs. Such errors don't vanish and can be inspected by turning on -Xlog-implicits. Unlike in typecheck, silent is true by default.

    Exceptions thrown
  6. 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. See enclosingPosition 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.

  7. 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 in mode with TERMmode being default.

    Typechecks the provided tree against the expected type pt in the macro callsite context under typechecking mode specified in mode with TERMmode 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. If silent is true, the typecheck is silent and will return EmptyTree if an error occurs. Such errors don't vanish and can be inspected by turning on -Ymacro-debug-verbose. Unlike in inferImplicitValue and inferImplicitView, 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 false withMacrosDisabled recursively prohibits macro expansions and macro-based implicits, default value is false

    Exceptions thrown
  8. 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://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.

    See also

    http://stackoverflow.com/questions/20936509/scala-macros-what-is-the-difference-between-typed-aka-typechecked-an-untyped

  9. 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

  1. val TypecheckException: macros.TypecheckException.type

    See also

    scala.reflect.macros.TypecheckException

Deprecated Value Members

  1. 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