Packages

abstract class Reifier extends States with Phases with Errors with Utils

Given a tree or a type, generate a tree that when executed at runtime produces the original tree or type. See more info in the comments to reify in scala.reflect.api.Universe.

Source
Reifier.scala
Version

2.10

Since

2.10

Known Subclasses
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Inherited
  1. Reifier
  2. Utils
  3. StdAttachments
  4. SymbolTables
  5. Extractors
  6. NodePrinters
  7. Errors
  8. Phases
  9. Reify
  10. GenUtils
  11. GenPositions
  12. GenAnnotationInfos
  13. GenTrees
  14. GenNames
  15. GenTypes
  16. GenSymbols
  17. Metalevels
  18. Calculate
  19. Reshape
  20. States
  21. AnyRef
  22. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Visibility
  1. Public
  2. All

Instance Constructors

  1. new Reifier()

Type Members

  1. class State extends AnyRef
    Definition Classes
    States
  2. 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
  3. implicit class RichCalculateSymbol extends AnyRef
    Definition Classes
    Calculate
  4. implicit class RichCalculateType extends AnyRef
    Definition Classes
    Calculate
  5. sealed abstract class FreeDefExtractor extends AnyRef
    Definition Classes
    Extractors
  6. case class ReifyAliasAttachment(sym: tools.nsc.Global.Symbol, alias: tools.nsc.Global.TermName) extends Product with Serializable
    Definition Classes
    StdAttachments
  7. case class ReifyBindingAttachment(binding: tools.nsc.Global.Tree) extends Product with Serializable
    Definition Classes
    StdAttachments
  8. class SymbolTable extends AnyRef
    Definition Classes
    SymbolTables

Abstract Value Members

  1. abstract val concrete: Boolean
  2. abstract val global: Global
    Definition Classes
    ReifierUtils
  3. abstract val mirror: tools.nsc.Global.Tree
  4. abstract val reifee: Any
  5. abstract val typer: (analyzer)#Typer
    Definition Classes
    ReifierUtils
  6. abstract val universe: tools.nsc.Global.Tree

Concrete Value Members

  1. def CannotConvertManifestToTagWithoutScalaReflect(tpe: tools.nsc.Global.Type, manifestInScope: tools.nsc.Global.Tree): Nothing
    Definition Classes
    Errors
  2. def CannotReifyCompoundTypeTreeWithNonEmptyBody(ctt: tools.nsc.Global.CompoundTypeTree): Nothing
    Definition Classes
    Errors
  3. def CannotReifyErroneousPrefix(prefix: tools.nsc.Global.Tree): Nothing
    Definition Classes
    Errors
  4. def CannotReifyErroneousReifee(reifee: Any): Nothing
    Definition Classes
    Errors
  5. def CannotReifyInvalidLazyVal(tree: tools.nsc.Global.ValDef): Nothing
    Definition Classes
    Errors
  6. def CannotReifyRuntimeSplice(tree: tools.nsc.Global.Tree): Nothing
    Definition Classes
    Errors
  7. def CannotReifyType(tpe: tools.nsc.Global.Type): Nothing
    Definition Classes
    Errors
  8. def CannotReifyUntypedPrefix(prefix: tools.nsc.Global.Tree): Nothing
    Definition Classes
    Errors
  9. def CannotReifyUntypedReifee(reifee: Any): Nothing
    Definition Classes
    Errors
  10. def CannotReifyWeakType(details: Any): Nothing
    Definition Classes
    Errors
  11. def boundSymbolsInCallstack: List[tools.nsc.Global.Symbol]
    Definition Classes
    Reify
  12. 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
  13. def call(fname: String, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  14. def current: Any
    Definition Classes
    Reify
  15. def currents: List[Any]
    Definition Classes
    Reify
  16. def defaultErrorPosition: tools.nsc.Global.Position
    Definition Classes
    Errors
  17. def getReifier: Reifier { val global: Reifier.this.global.type }
    Definition Classes
    ReifierUtils
  18. def hasReifier: Boolean
    Definition Classes
    ReifierUtils
  19. def isCrossStageTypeBearer(tree: tools.nsc.Global.Tree): Boolean
    Definition Classes
    GenUtils
  20. def isSemiConcreteTypeMember(tpe: tools.nsc.Global.Type): Boolean
    Definition Classes
    GenUtils
  21. 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
  22. def mirrorBuildCall(name: tools.nsc.Global.TermName, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  23. def mirrorCall(name: tools.nsc.Global.TermName, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  24. def mirrorFactoryCall(prefix: tools.nsc.Global.TermName, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  25. def mirrorFactoryCall(value: Product, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  26. def mirrorMirrorCall(name: tools.nsc.Global.TermName, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  27. def mirrorMirrorSelect(name: tools.nsc.Global.TermName): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  28. def mirrorSelect(name: tools.nsc.Global.TermName): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  29. def mirrorSelect(name: String): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  30. def mkList(args: List[tools.nsc.Global.Tree]): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  31. def mkListMap(args: List[tools.nsc.Global.Tree]): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  32. lazy val mkReificationPipeline: (tools.nsc.Global.Tree) ⇒ tools.nsc.Global.Tree
    Definition Classes
    Phases
  33. def origin(sym: tools.nsc.Global.Symbol): String
    Definition Classes
    GenUtils
  34. 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
  35. lazy val reification: tools.nsc.Global.Tree

    For reifee and other reification parameters, generate a tree of the form

    For reifee and other reification parameters, generate a tree of the form

    {
      val $u: universe.type = <[ universe ]>
      val $m: $u.Mirror = <[ mirror ]>
      $u.Expr[T](rtree)       // if data is a Tree
      $u.TypeTag[T](rtree)    // if data is a Type
    }

    where

    • universe is the tree that represents the universe the result will be bound to.
    • mirror is the tree that represents the mirror the result will be initially bound to.
    • rtree is code that generates reifee at runtime.
    • T is the type that corresponds to data.

    This is not a method, but a value to indicate the fact that Reifier instances are a one-off.

  36. 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
  37. lazy val reifier: Reifier { val global: Reifier.this.global.type }
    Definition Classes
    Utils
  38. 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
  39. def reifyAnnotationInfo(ann: tools.nsc.Global.AnnotationInfo): tools.nsc.Global.Tree
    Definition Classes
    GenAnnotationInfos
  40. def reifyBinding(tree: tools.nsc.Global.Tree): tools.nsc.Global.Tree
    Definition Classes
    StdAttachments
  41. def reifyBuildCall(name: tools.nsc.Global.TermName, args: Any*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  42. val reifyCopypaste: Boolean
    Definition Classes
    Utils
  43. val reifyDebug: Boolean
    Definition Classes
    Utils
  44. def reifyFlags(flags: tools.nsc.Global.FlagSet): tools.nsc.Global.Tree
    Definition Classes
    GenTrees
  45. def reifyFreeTerm(binding: tools.nsc.Global.Tree): tools.nsc.Global.Tree
    Definition Classes
    GenSymbols
  46. def reifyFreeType(binding: tools.nsc.Global.Tree): tools.nsc.Global.Tree
    Definition Classes
    GenSymbols
  47. def reifyList(xs: List[Any]): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  48. def reifyMirrorObject(x: Product): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  49. 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
  50. def reifyModifiers(m: tools.nsc.Global.Modifiers): tools.nsc.Global.Tree
    Definition Classes
    GenTrees
  51. def reifyName(name: tools.nsc.Global.Name): tools.nsc.Global.Tree
    Definition Classes
    GenNames
  52. def reifyPosition(pos: tools.nsc.Global.Position): tools.nsc.Global.Tree
    Definition Classes
    GenPositions
  53. def reifyProduct(prefix: String, elements: List[Any]): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  54. def reifyProduct(x: Product): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  55. def reifySymDef(sym: tools.nsc.Global.Symbol): tools.nsc.Global.Tree
    Definition Classes
    GenSymbols
  56. 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
  57. val reifyTrace: SimpleTracer
    Definition Classes
    Utils
  58. 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
  59. def reifyTreeSymbols: Boolean
    Definition Classes
    GenTrees
  60. def reifyTreeSyntactically(tree: tools.nsc.Global.Tree): tools.nsc.Global.Tree
    Definition Classes
    GenTrees
  61. def reifyTreeTypes: Boolean
    Definition Classes
    GenTrees
  62. 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
  63. 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
  64. def scalaFactoryCall(name: String, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  65. def scalaFactoryCall(name: tools.nsc.Global.TermName, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
    GenUtils
  66. def spliceType(tpe: tools.nsc.Global.Type): tools.nsc.Global.Tree
    Definition Classes
    GenTypes
  67. val state: State

    Encapsulates reifier state

    Encapsulates reifier state

    When untangling reifier symbol tables from the reifier itself, I discovered that encoding of a symbol table (e.g. producing corresponding reificode) might cause subsequent reification (e.g. when filling in signatures and annotations for syms).

    This is a mess in the face of nested reifications, splices and inlining of thereof, so I made SymbolTable immutable, which brought a significant amount of sanity.

    However that wasn't enough. Sure, symbol table became immutable, but the reifier still needed to mutate its symtab field during reification. This caused nasty desyncs between the table being encoded and the table of the underlying reifier, so I decided to encapsulate the entire state here, so that encoding can backup the state before it starts and restore it after it completes.

    Definition Classes
    States
  68. def symtab: 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
  69. 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
  70. object TypedOrAnnotated
    Definition Classes
    GenUtils
  71. object ApplyCall
    Definition Classes
    Extractors
  72. object BoundTerm
    Definition Classes
    Extractors
  73. object BoundType
    Definition Classes
    Extractors
  74. object FreeDef extends Utils.FreeDefExtractor
    Definition Classes
    Extractors
  75. object FreeRef
    Definition Classes
    Extractors
  76. object FreeTermDef extends Utils.FreeDefExtractor
    Definition Classes
    Extractors
  77. object FreeTypeDef extends Utils.FreeDefExtractor
    Definition Classes
    Extractors
  78. object ReifiedTree
    Definition Classes
    Extractors
  79. object ReifiedType
    Definition Classes
    Extractors
  80. object SymDef
    Definition Classes
    Extractors
  81. object TreeSplice
    Definition Classes
    Extractors
  82. object TypeRefToFreeType
    Definition Classes
    Extractors
  83. object reifiedNodeToString extends (tools.nsc.Global.Tree) ⇒ String
    Definition Classes
    NodePrinters
  84. object SymbolTable
    Definition Classes
    SymbolTables