diff options
author | Adriaan Moors <adriaan.moors@epfl.ch> | 2010-09-16 22:26:24 +0000 |
---|---|---|
committer | Adriaan Moors <adriaan.moors@epfl.ch> | 2010-09-16 22:26:24 +0000 |
commit | e557acb9a7d672c0635c3eaf9fe385adc41e5c86 (patch) | |
tree | d13db6639464acc57f0e44b4b3ef6f3e607ad403 /test/files/pos/depmet_implicit_oopsla_session_2.scala | |
parent | ce223fe7abc47af712382a64404604e75f9f4d20 (diff) | |
download | scala-e557acb9a7d672c0635c3eaf9fe385adc41e5c86.tar.gz scala-e557acb9a7d672c0635c3eaf9fe385adc41e5c86.tar.bz2 scala-e557acb9a7d672c0635c3eaf9fe385adc41e5c86.zip |
part 2 of the dependent method refactoring: imp...
part 2 of the dependent method refactoring: improved interaction with
implicit search (needed for oopsla paper)
more to come in this area, see e.g. #3346 (stanford edsl stuff)
reopens #13, which wasn't fixed properly before imo, anyway (have a look at -Xprint:typer output before this commit: a type that's not expressible in surface syntax is inferred -- also removed duplicate test file)
closes #3731: co-evolve type alias type symbols when their rhs is
updated and they are referenced by type selections (see typemap)
review by odersky
Diffstat (limited to 'test/files/pos/depmet_implicit_oopsla_session_2.scala')
-rw-r--r-- | test/files/pos/depmet_implicit_oopsla_session_2.scala | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/test/files/pos/depmet_implicit_oopsla_session_2.scala b/test/files/pos/depmet_implicit_oopsla_session_2.scala new file mode 100644 index 0000000000..5c3b78e3f5 --- /dev/null +++ b/test/files/pos/depmet_implicit_oopsla_session_2.scala @@ -0,0 +1,87 @@ +object Sessions { + def ?[T <: AnyRef](implicit w: T): w.type = w + + // session states + sealed case class Stop() + sealed case class In[-Data, +Cont](recv: Data => Cont) + sealed case class Out[+Data, +Cont](data: Data, cont: Cont) + + // the type theory of communicating sessions: + + // an instance of type Session[S]{type Dual=D} is evidence that S and D are duals + // such a value witnesses this fact by describing how to compose an instance of S with an instance of D (through the run method) + trait Session[S] { type Self = S + type Dual + type HasDual[D] = Session[Self]{type Dual=D} + def run(self: Self, dual: Dual): Unit + } + + // friendly interface to the theory + def runSession[S, D: Session[S]#HasDual](session: S, dual: D) = + ?[Session[S]#HasDual[D]].run(session, dual) + + // facts in the theory: + + // ------------------------[StopDual] + // Stop is the dual of Stop + implicit object StopDual extends Session[Stop] { + type Dual = Stop + + def run(self: Self, dual: Dual): Unit = {} + } + + // CD is the dual of Cont + // -------------------------------------------[InDual] + // Out[Data, CD] is the dual of In[Data, Cont] + implicit def InDual[Data, Cont](implicit cont: Session[Cont]) = new Session[In[Data, Cont]] { + type Dual = Out[Data, cont.Dual] + + def run(self: Self, dual: Dual): Unit = + cont.run(self.recv(dual.data), dual.cont) + } + + // CD is the dual of Cont + // -------------------------------------------[OutDual] + // In[Data, CD] is the dual of Out[Data, Cont] + implicit def OutDual[Data, Cont](implicit cont: Session[Cont]) = new Session[Out[Data, Cont]] { + type Dual = In[Data, cont.Dual] + + def run(self: Self, dual: Dual): Unit = + cont.run(self.cont, dual.recv(self.data)) + } + + // a concrete session + def addServer = + In{x: Int => + In{y: Int => System.out.println("Thinking") + Out(x+y, + Stop())}} + + def addClient = + Out(3, + Out(4, { System.out.println("Waiting") + In{z: Int => System.out.println(z) + Stop()}})) + + def myRun = runSession(addServer, addClient) +} + +/* future improvements: + + + // def runSession[S, D](p: S, dp: D)(implicit s: Session[S]#HasDual[D]) = + // s.run(p, dp) + // + // def runSession[S, D](p: S, dp: D)(implicit s: Session[S]{type Dual=D}) = + // s.run(p, dp) + + // TODO: can we relax the ordering restrictions on dependencies so that we can write + // one possibility: graph of dependencies between arguments must be acyclic + // def runSession[S](p: S, dp: s.Dual)(implicit s: Session[S]) = + // s.run(p, dp) + // to emphasise similarity of type parameters and implicit arguments: + // def runSession[S][val s: Session[S]](p: S, dp: s.Dual) = + // s.run(p, dp) + + +*/
\ No newline at end of file |