Packages

trait Phases extends Reshape with Calculate with Metalevels with Reify

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Inherited
  1. Phases
  2. Reify
  3. GenUtils
  4. GenPositions
  5. GenAnnotationInfos
  6. GenTrees
  7. GenNames
  8. GenTypes
  9. GenSymbols
  10. Metalevels
  11. Calculate
  12. Reshape
  13. AnyRef
  14. Any
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  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Type Members

  1. case class Reification(name: tools.nsc.Global.Name, binding: tools.nsc.Global.Tree, tree: tools.nsc.Global.Tree) extends Product with Serializable
    Definition Classes
    GenSymbols
  2. implicit class RichCalculateSymbol extends AnyRef
    Definition Classes
    Calculate
  3. implicit class RichCalculateType extends AnyRef
    Definition Classes
    Calculate

Value Members

  1. def boundSymbolsInCallstack: List[tools.nsc.Global.Symbol]
    Definition Classes
    Reify
  2. val calculate: tools.nsc.Global.Traverser { ... /* 2 definitions in type refinement */ }

    Merely traverses the reifiee and records symbols local to the reifee along with their metalevels.

    Merely traverses the reifiee and records symbols local to the reifee along with their metalevels.

    Definition Classes
    Calculate
  3. def call(fname: String, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  4. def current: Any
    Definition Classes
    Reify
  5. def currents: List[Any]
    Definition Classes
    Reify
  6. def isCrossStageTypeBearer(tree: tools.nsc.Global.Tree): Boolean
    Definition Classes
    GenUtils
  7. def isSemiConcreteTypeMember(tpe: tools.nsc.Global.Type): Boolean
    Definition Classes
    GenUtils
  8. val metalevels: tools.nsc.Global.Transformer { ... /* 4 definitions in type refinement */ }

    Makes sense of cross-stage bindings.

    Makes sense of cross-stage bindings.


    Analysis of cross-stage bindings becomes convenient if we introduce the notion of metalevels. Metalevel of a tree is a number that gets incremented every time you reify something and gets decremented when you splice something. Metalevel of a symbol is equal to the metalevel of its definition.

    Example 1. Consider the following snippet:

    reify { val x = 2 // metalevel of symbol x is 1, because it's declared inside reify val y = reify{x} // metalevel of symbol y is 1, because it's declared inside reify // metalevel of Ident(x) is 2, because it's inside two reifies y.splice // metalevel of Ident(y) is 0, because it's inside a designator of a splice }

    Cross-stage bindings are introduced when symbol.metalevel != curr_metalevel. Both bindings introduced in Example 1 are cross-stage.

    Depending on what side of the inequality is greater, the following situations might occur:

    1) symbol.metalevel < curr_metalevel. In this case reifier will generate a free variable that captures both the name of the symbol (to be compiled successfully) and its value (to be run successfully). For example, x in Example 1 will be reified as follows: Ident(newFreeVar("x", IntTpe, x))

    2) symbol.metalevel > curr_metalevel. This leads to a metalevel breach that violates intuitive perception of splicing. As defined in macro spec, splicing takes a tree and inserts it into another tree - as simple as that. However, how exactly do we do that in the case of y.splice? In this very scenario we can use dataflow analysis and inline it, but what if y were a var, and what if it were calculated randomly at runtime?

    This question has a genuinely simple answer. Sure, we cannot resolve such splices statically (i.e. during macro expansion of reify), but now we have runtime toolboxes, so noone stops us from picking up that reified tree and evaluating it at runtime (in fact, this is something that Expr.splice does transparently).

    This is akin to early vs late binding dilemma. The prior is faster, plus, the latter (implemented with reflection) might not work because of visibility issues or might be not available on all platforms. But the latter still has its uses, so I'm allowing metalevel breaches, but introducing the -Xlog-runtime-evals to log them.

    upd. We no longer do that. In case of a runaway splice inside a reify, one will get a static error. Why? Unfortunately, the cute idea of transparently converting between static and dynamic splices has failed. 1) Runtime eval that services dynamic splices requires scala-compiler.jar, which might not be on library classpath 2) Runtime eval incurs a severe performance penalty, so it'd better to be explicit about it


    As we can see, the only problem is the fact that lhs'es of splice can be code blocks that can capture variables from the outside. Code inside the lhs of an splice is not reified, while the code from the enclosing reify is.

    Hence some bindings become cross-stage, which is not bad per se (in fact, some cross-stage bindings have sane semantics, as in the example above). However this affects freevars, since they are delicate inter-dimensional beings that refer to both current and next planes of existence. When splicing tears the fabric of the reality apart, some freevars have to go single-dimensional to retain their sanity.

    Example 2. Consider the following snippet:

    reify { val x = 2 reify{x}.splice }

    Since the result of the inner reify is wrapped in a splice, it won't be reified together with the other parts of the outer reify, but will be inserted into that result verbatim.

    The inner reify produces an Expr[Int] that wraps Ident(freeVar("x", IntTpe, x)). However the freevar the reification points to will vanish when the compiler processes the outer reify. That's why we need to replace that freevar with a regular symbol that will point to reified x.

    Example 3. Consider the following fragment:

    reify { val x = 2 val y = reify{x} y.splice }

    In this case the inner reify doesn't appear next to splice, so it will be reified together with x. This means that no special processing is needed here.

    Example 4. Consider the following fragment:

    reify { val x = 2 { val y = 2 val z = reify{reify{x + y}} z.splice }.splice }

    The reasoning from Example 2 still holds here - we do need to inline the freevar that refers to x. However, we must not touch anything inside the splice'd block, because it's not getting reified.

    Definition Classes
    Metalevels
  9. def mirrorBuildCall(name: tools.nsc.Global.TermName, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  10. def mirrorCall(name: tools.nsc.Global.TermName, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  11. def mirrorFactoryCall(prefix: tools.nsc.Global.TermName, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  12. def mirrorFactoryCall(value: Product, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  13. def mirrorMirrorCall(name: tools.nsc.Global.TermName, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  14. def mirrorMirrorSelect(name: tools.nsc.Global.TermName): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  15. def mirrorSelect(name: tools.nsc.Global.TermName): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  16. def mirrorSelect(name: String): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  17. def mkList(args: List[tools.nsc.Global.Tree]): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  18. def mkListMap(args: List[tools.nsc.Global.Tree]): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  19. lazy val mkReificationPipeline: (tools.nsc.Global.Tree) ⇒ tools.nsc.Global.Tree
  20. def origin(sym: tools.nsc.Global.Symbol): String
    Definition Classes
    GenUtils
  21. def path(fullname: String, mkName: (String) ⇒ tools.nsc.Global.Name): tools.nsc.Global.Tree

    An (unreified) path that refers to definition with given fully qualified name

    An (unreified) path that refers to definition with given fully qualified name

    mkName

    Creator for last portion of name (either TermName or TypeName)

    Definition Classes
    GenUtils
  22. def reificationIsConcrete: Boolean

    Keeps track of whether this reification contains abstract type parameters

    Keeps track of whether this reification contains abstract type parameters

    Definition Classes
    GenTypes
  23. def reify(reifee: Any): tools.nsc.Global.Tree

    Reifies any supported value.

    Reifies any supported value. For internal use only, use reified instead.

    Definition Classes
    Reify
  24. def reifyAnnotationInfo(ann: tools.nsc.Global.AnnotationInfo): tools.nsc.Global.Tree
    Definition Classes
    GenAnnotationInfos
  25. def reifyBuildCall(name: tools.nsc.Global.TermName, args: Any*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  26. def reifyFlags(flags: tools.nsc.Global.FlagSet): tools.nsc.Global.Tree
    Definition Classes
    GenTrees
  27. def reifyFreeTerm(binding: tools.nsc.Global.Tree): tools.nsc.Global.Tree
    Definition Classes
    GenSymbols
  28. def reifyFreeType(binding: tools.nsc.Global.Tree): tools.nsc.Global.Tree
    Definition Classes
    GenSymbols
  29. def reifyList(xs: List[Any]): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  30. def reifyMirrorObject(x: Product): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  31. def reifyMirrorObject(name: String): tools.nsc.Global.Tree

    Reify a case object defined in Mirror

    Reify a case object defined in Mirror

    Definition Classes
    GenUtils
  32. def reifyModifiers(m: tools.nsc.Global.Modifiers): tools.nsc.Global.Tree
    Definition Classes
    GenTrees
  33. def reifyName(name: tools.nsc.Global.Name): tools.nsc.Global.Tree
    Definition Classes
    GenNames
  34. def reifyPosition(pos: tools.nsc.Global.Position): tools.nsc.Global.Tree
    Definition Classes
    GenPositions
  35. def reifyProduct(prefix: String, elements: List[Any]): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  36. def reifyProduct(x: Product): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  37. def reifySymDef(sym: tools.nsc.Global.Symbol): tools.nsc.Global.Tree
    Definition Classes
    GenSymbols
  38. def reifySymRef(sym: tools.nsc.Global.Symbol): tools.nsc.Global.Tree

    Reify a reference to a symbol

    Reify a reference to a symbol

    Definition Classes
    GenSymbols
  39. def reifyTree(tree: tools.nsc.Global.Tree): tools.nsc.Global.Tree

    Reify a tree.

    Reify a tree. For internal use only, use reified instead.

    Definition Classes
    GenTrees
  40. def reifyTreeSymbols: Boolean
    Definition Classes
    GenTrees
  41. def reifyTreeSyntactically(tree: tools.nsc.Global.Tree): tools.nsc.Global.Tree
    Definition Classes
    GenTrees
  42. def reifyTreeTypes: Boolean
    Definition Classes
    GenTrees
  43. def reifyType(tpe: tools.nsc.Global.Type): tools.nsc.Global.Tree

    Reify a type.

    Reify a type. For internal use only, use reified instead.

    Definition Classes
    GenTypes
  44. val reshape: tools.nsc.Global.Transformer { ... /* 2 definitions in type refinement */ }

    Rolls back certain changes that were introduced during typechecking of the reifee.

    Rolls back certain changes that were introduced during typechecking of the reifee.

    These include: * Undoing macro expansions * Replacing type trees with TypeTree(tpe) * Reassembling CompoundTypeTrees into reifiable form * Transforming Modifiers.annotations into Symbol.annotations * Transforming Annotated annotations into AnnotatedType annotations * Transforming Annotated(annot, expr) into Typed(expr, TypeTree(Annotated(annot, _)) * Non-idempotencies of the typechecker: https://github.com/scala/bug/issues/5464

    Definition Classes
    Reshape
  45. def scalaFactoryCall(name: String, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  46. def scalaFactoryCall(name: tools.nsc.Global.TermName, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  47. def spliceType(tpe: tools.nsc.Global.Type): tools.nsc.Global.Tree
    Definition Classes
    GenTypes
  48. def symtab: Reifier.SymbolTable

    Symbol table of the reifee.

    Symbol table of the reifee.

    Keeps track of auxiliary symbols that are necessary for this reification session. These include: 1) Free vars (terms, types and existentials), 2) Non-locatable symbols (sometimes, e.g. for RefinedTypes, we need to reify these; to do that we create their copies in the reificode) 3) Non-locatable symbols that are referred by #1, #2 and #3

    Exposes three main methods: 1) syms that lists symbols belonging to the table, 2) symXXX family of methods that provide information about the symbols in the table, 3) encode that renders the table into a list of trees (recursively populating #3 and setting up initialization code for #1, #2 and #3)

    Definition Classes
    GenSymbols
  49. def termPath(fullname: String): tools.nsc.Global.Tree

    An (unreified) path that refers to term definition with given fully qualified name

    An (unreified) path that refers to term definition with given fully qualified name

    Definition Classes
    GenUtils
  50. object TypedOrAnnotated
    Definition Classes
    GenUtils