Splicing

dotty.tools.dotc.transform.Splicing
See theSplicing companion object
class Splicing extends MacroTransform

Transforms level 1 splices into holes. To do so it transforms the contents of the splice into a lambda that receives all cross-quote references.

Cross-quote reference is a reference to a definition that is not defined in the current quote. Those references appear in quotes that are nested in a splice.

After this phase we have the invariant where all splices have the following shape

{{{ <holeIdx> | <holeType> | <captures>* | (<capturedTerms>*) => <spliceContent> 
}}}

where <spliceContent> does not contain any free references to quoted definitions and <captures>* contains the quotes with references to all cross-quote references. There are some special rules for references in the LHS of assignments and cross-quote method references.

In the following code example x1 and x2 are cross-quote references.

'{ ...
  val x1: T1 = ???
  val x2: T2 = ???
  ${ (q: Quotes) ?=> f('{ g(x1, x2) }) }: T3
}

This phase identifies cross-quote references such as x1 and replaces it with an ${x1$}. All cross-quote arguments are directly applied in the lambda.

'{ ...
   val x1: T1 = ???
   val x2: T2 = ???
{{{
 0 | T3 | x1, x2 |
     (x1$: Expr[T1], x2$: Expr[T2]) => // body of this lambda does not contain references to x1 or x2
       (q: Quotes) ?=> f('{ g(${x1$}, ${x2$}) })

}}}
 }

and then performs the same transformation on '{ g(${x1$}, ${x2$}) }.

Attributes

Companion
object
Graph
Supertypes
class Phase
class Object
trait Matchable
class Any

Members list

Type members

Inherited classlikes

Attributes

Inherited from:
MacroTransform
Supertypes
class TreeMap
class Object
trait Matchable
class Any
Known subtypes

Value members

Concrete methods

override def phaseName: String

A name given to the Phase that can be used to debug the compiler. For instance, it is possible to print trees after a given phase using:

A name given to the Phase that can be used to debug the compiler. For instance, it is possible to print trees after a given phase using:

$ ./bin/scalac -Xprint:<phaseNameHere> sourceFile.scala

Attributes

Definition Classes
override def run(using Context): Unit

Attributes

Definition Classes

Inherited methods

final def <=(that: Phase): Boolean

Attributes

Inherited from:
Phase

If set, implicit search is enabled

If set, implicit search is enabled

Attributes

Inherited from:
Phase

Can this transform change the base types of a type?

Can this transform change the base types of a type?

Attributes

Inherited from:
Phase

Can this transform create or delete non-private members?

Can this transform create or delete non-private members?

Attributes

Inherited from:
Phase

Can this transform change the parents of a class?

Can this transform change the parents of a class?

Attributes

Inherited from:
Phase
def checkPostCondition(tree: Tree)(using Context): Unit

Check what the phase achieves, to be called at any point after it is finished.

Check what the phase achieves, to be called at any point after it is finished.

Attributes

Inherited from:
Phase

Attributes

Inherited from:
Phase
def end: PhaseId

Attributes

Inherited from:
Phase
final def erasedTypes: Boolean

Attributes

Inherited from:
Phase

Attributes

Inherited from:
Phase
final def flatClasses: Boolean

Attributes

Inherited from:
Phase
final def hasNext: Boolean

Attributes

Inherited from:
Phase
def id: Int

The sequence position of this phase in the given context where 0 is reserved for NoPhase and the first real phase is at position 1. -1 if the phase is not installed in the context.

The sequence position of this phase in the given context where 0 is reserved for NoPhase and the first real phase is at position 1. -1 if the phase is not installed in the context.

Attributes

Inherited from:
Phase

Attributes

Inherited from:
Phase

Output should be checkable by TreeChecker

Output should be checkable by TreeChecker

Attributes

Inherited from:
Phase
def isEnabled(using Context): Boolean

Attributes

Inherited from:
Phase
def isRunnable(using Context): Boolean

Attributes

Inherited from:
Phase

Is this phase the standard typerphase? True for TyperPhase, but not for other first phases (such as FromTasty or Parser). The predicate is tested in some places that perform checks and corrections. It's different from ctx.isAfterTyper (and cheaper to test).

Is this phase the standard typerphase? True for TyperPhase, but not for other first phases (such as FromTasty or Parser). The predicate is tested in some places that perform checks and corrections. It's different from ctx.isAfterTyper (and cheaper to test).

Attributes

Inherited from:
Phase
final def iterator: Iterator[Phase]

Attributes

Inherited from:
Phase
final def lambdaLifted: Boolean

Attributes

Inherited from:
Phase
final def monitor(doing: String)(body: => Unit)(using Context): Unit

Attributes

Inherited from:
Phase
final def next: Phase

Attributes

Inherited from:
Phase

Attributes

Inherited from:
Phase
def period: Period

Attributes

Inherited from:
Phase
final def prev: Phase

Attributes

Inherited from:
Phase
final def prevMega(using Context): Phase

Attributes

Inherited from:
Phase
final def refChecked: Boolean

Attributes

Inherited from:
Phase

If set, allow missing or superfluous arguments in applications and type applications.

If set, allow missing or superfluous arguments in applications and type applications.

Attributes

Inherited from:
Phase

Attributes

Inherited from:
Phase

List of names of phases that should precede this phase

List of names of phases that should precede this phase

Attributes

Inherited from:
Phase

Attributes

Inherited from:
Phase
final def sameMembersStartId: Int

Attributes

Inherited from:
Phase
final def sameParentsStartId: Int

Attributes

Inherited from:
Phase
def show(tree: Tree)(using Context): String

Convert a compilation unit's tree to a string; can be overridden

Convert a compilation unit's tree to a string; can be overridden

Attributes

Inherited from:
Phase
def start: Int

Attributes

Inherited from:
Phase
override def toString: String

Returns a string representation of the object.

Returns a string representation of the object.

The default representation is platform dependent.

Attributes

Returns

a string representation of the object.

Definition Classes
Phase -> Any
Inherited from:
Phase
protected def transformPhase(using Context): Phase

The phase in which the transformation should be run. By default this is the phase given by the this macro transformer, but it could be overridden to be the phase following that one.

The phase in which the transformation should be run. By default this is the phase given by the this macro transformer, but it could be overridden to be the phase following that one.

Attributes

Inherited from:
MacroTransform