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  1. /* Example of case class */
  2.  
  3. abstract class Term
  4.  
  5. case class Var(name: String) extends Term
  6. case class Fun(arg: String, body: Term) extends Term
  7. case class App(f: Term, v: Term) extends Term
  8.  
  9. object TermTest extends Application {
  10.     def printTerm(term: Term) {
  11.         term match {
  12.             case Var(n) =>
  13.                 print(n)
  14.             case Fun(x, b) =>
  15.                 print("^" + x + ".")
  16.                 printTerm(b)
  17.             case App(f, v) =>
  18.                 Console.print("(")
  19.                 printTerm(f)
  20.                 print(" ")
  21.                 printTerm(v)
  22.                 print(")")
  23.         }
  24.     }
  25.     def isIdentityFun(term: Term): Boolean = term match {
  26.         case Fun(x, Var(y)) if x == y => true
  27.         case _ => false
  28.     }
  29.     val id = Fun("x", Var("x"))
  30.     val t = Fun("x", Fun("y", App(Var("x"), Var("y"))))
  31.     printTerm(t)
  32.     println
  33.     println(isIdentityFun(id))
  34.     println(isIdentityFun(t))
  35. }
  36.  
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https://ideone.com/Ao9KER
language:
Scala (scala 2.12.8)
created:
9 years ago
visibility:
public

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