scala.tools.nsc.typechecker.PatternMatching.TreeMakers
The substitution that specifies the trees that compute the values of the subpattern binders.
The substitution that specifies the trees that compute the values of the subpattern binders.
We pretend to replace the subpattern binders by subpattern refs (Even though we don't do so anymore -- see SI-5158, SI-5739 and SI-6070.)
captures the scope and the value of the bindings in patterns important *when* the substitution happens (can't accumulate and do at once after the full matcher has been constructed)
captures the scope and the value of the bindings in patterns important *when* the substitution happens (can't accumulate and do at once after the full matcher has been constructed)
(productExtractorTreeMaker: StringAdd).self
(productExtractorTreeMaker: StringFormat).self
(productExtractorTreeMaker: ArrowAssoc[(TreeMakers.this)#ProductExtractorTreeMaker]).x
(Since version 2.10.0) Use leftOfArrow
instead
(productExtractorTreeMaker: Ensuring[(TreeMakers.this)#ProductExtractorTreeMaker]).x
(Since version 2.10.0) Use resultOfEnsuring
instead
An optimized version of ExtractorTreeMaker for Products. For now, this is hard-coded to case classes, and we simply extract the case class fields.
The values for the subpatterns, as specified by the case class fields at the time of extraction, are stored in local variables that re-use the symbols in
subPatBinders
. This makes extractor patterns more debuggable (SI-5739) as well as avoiding mutation after the pattern has been matched (SI-5158, SI-6070)TODO: make this user-definable as follows When a companion object defines a method
def unapply_1(x: T): U_1
, but nodef unapply
ordef unapplySeq
, the extractor is considered to match any non-null value of type T the pattern is expected to have as many sub-patterns as there aredef unapply_I(x: T): U_I
methods, and the type of the I'th sub-pattern isU_I
. The same exception for Seq patterns applies: if the last extractor is of typeSeq[U_N]
, the pattern must have at least N arguments (exactly N if the last argument is annotated with: _*
). The arguments starting at N (and beyond) are taken from the sequence returned by apply_N, and it is checked that that sequence has enough elements to provide values for all expected sub-patterns.For a case class C, the implementation is assumed to be
def unapply_I(x: C) = x._I
, and the extractor call is inlined under that assumption.