Initial commit.

1 files changed, 53 insertions, 0 deletions

diff --git a/CLTerms.scala b/CLTerms.scala
new file mode 100644
index 0000000..5822428
--- /dev/null
+++ b/CLTerms.scala
@@ -0,0 +1,53 @@
+package object cl {
+  sealed trait Term {
+    def *(that: Term) = cl.*(this, that)
+
+    // Given a term M and variable x, M.extract(x) returns a term
+    // without x, M', s.t. (M' * x) evaluates the same way as M
+    def extract(x: Var): Term = this match {
+      case a: Atom if a != x => K * a
+      case a: Atom if a == x => I
+      case l * r => S * l.extract(x) * r.extract(x)
+    }
+
+    def contains(x: Var): Boolean = ???
+  }
+
+  case class *(left: Term, right: Term) extends Term {
+    override def toString = this match {
+      case p * (q * r) => s"$p(${q * r})"
+      case _ => s"$left$right"
+    }
+  }
+
+  def eval(t: Term): Term = ???
+
+  def bracketAbstraction(f: Term => Term): Term = {
+    val x = Var("variable")
+    f(x).extract(x)
+  }
+
+  def bracketAbstraction(f: (Term, Term) => Term): Term = {
+    val x = Var("variable-x")
+    val y = Var("variable-y")
+    f(x, y).extract(y).extract(x)
+  }
+
+  sealed trait Atom extends Term
+  sealed trait Const extends Atom
+  case object S extends Const
+  case object K extends Const
+  case object I extends Const
+  case object B extends Const
+  case object C extends Const
+  case object W extends Const
+  case object Bp extends Const
+  case object Cp extends Const
+  case object Sp extends Const
+
+  case class Var(name: String) extends Atom {
+    override def toString = name
+  }
+
+  implicit def symbolToVar(s: Symbol) = new Var(s.name)
+}