Created proper 'docs' folder for new layout.

1 files changed, 0 insertions, 244 deletions

diff --git a/sources/examples/typeinf.scala b/sources/examples/typeinf.scala
deleted file mode 100644
index a9ac59968b..0000000000
--- a/sources/examples/typeinf.scala
+++ /dev/null
@@ -1,244 +0,0 @@
-package examples;
-
-object typeinf {
-
-trait Term {}
-
-case class Var(x: String)                   extends Term {
-  override def toString() = x
-}
-case class Lam(x: String, e: Term)          extends Term {
-  override def toString() = "(\\" + x + "." + e + ")"
-}
-case class App(f: Term, e: Term)            extends Term {
-  override def toString() = "(" + f + " " + e + ")"
-}
-case class Let(x: String, e: Term, f: Term) extends Term {
-  override def toString() = "let " + x + " = " + e + " in " + f;
-}
-
-sealed trait Type {}
-case class Tyvar(a: String) extends Type {
-  override def toString() = a
-}
-case class Arrow(t1: Type, t2: Type) extends Type {
-  override def toString() = "(" + t1 + "->" + t2 + ")"
-}
-case class Tycon(k: String, ts: List[Type]) extends Type {
-  override def toString() =
-    k + (if (ts.isEmpty) "" else ts.mkString("[", ",", "]"))
-}
-
-object typeInfer {
-
-  private var n: Int = 0;
-  def newTyvar(): Type = { n = n + 1 ; Tyvar("a" + n) }
-
-  trait Subst with Function1[Type,Type] {
-    def lookup(x: Tyvar): Type;
-    def apply(t: Type): Type = t match {
-      case tv @ Tyvar(a) => val u = lookup(tv); if (t == u) t else apply(u);
-      case Arrow(t1, t2) => Arrow(apply(t1), apply(t2))
-      case Tycon(k, ts) => Tycon(k, ts map apply)
-    }
-    def extend(x: Tyvar, t: Type) = new Subst {
-      def lookup(y: Tyvar): Type = if (x == y) t else Subst.this.lookup(y);
-    }
-  }
-
-  val emptySubst = new Subst { def lookup(t: Tyvar): Type = t }
-
-  case class TypeScheme(tyvars: List[Tyvar], tpe: Type) {
-    def newInstance: Type =
-      (emptySubst /: tyvars) ((s, tv) => s.extend(tv, newTyvar())) (tpe);
-  }
-
-  type Env = List[Pair[String, TypeScheme]];
-
-  def lookup(env: Env, x: String): TypeScheme = env match {
-    case List() => null
-    case Pair(y, t) :: env1 => if (x == y) t else lookup(env1, x)
-  }
-
-  def gen(env: Env, t: Type): TypeScheme =
-    TypeScheme(tyvars(t) diff tyvars(env), t);
-
-  def tyvars(t: Type): List[Tyvar] = t match {
-    case tv @ Tyvar(a) => List(tv)
-    case Arrow(t1, t2) => tyvars(t1) union tyvars(t2)
-    case Tycon(k, ts) => (List[Tyvar]() /: ts) ((tvs, t) => tvs union tyvars(t));
-  }
-
-  def tyvars(ts: TypeScheme): List[Tyvar] =
-    tyvars(ts.tpe) diff ts.tyvars;
-
-  def tyvars(env: Env): List[Tyvar] =
-    (List[Tyvar]() /: env) ((tvs, nt) => tvs union tyvars(nt._2));
-
-  def mgu(t: Type, u: Type, s: Subst): Subst = Pair(s(t), s(u)) match {
-    case Pair(Tyvar(a), Tyvar(b)) if (a == b) =>
-      s
-    case Pair(Tyvar(a), _) if !(tyvars(u) contains a) =>
-      s.extend(Tyvar(a), u)
-    case Pair(_, Tyvar(a)) =>
-      mgu(u, t, s)
-    case Pair(Arrow(t1, t2), Arrow(u1, u2)) =>
-      mgu(t1, u1, mgu(t2, u2, s))
-    case Pair(Tycon(k1, ts), Tycon(k2, us)) if (k1 == k2) =>
-      (s /: (ts zip us)) ((s, tu) => mgu(tu._1, tu._2, s))
-    case _ => throw new TypeError("cannot unify " + s(t) + " with " + s(u))
-  }
-
-  case class TypeError(s: String) extends Exception(s) {}
-
-  def tp(env: Env, e: Term, t: Type, s: Subst): Subst = {
-    current = e;
-    e match {
-      case Var(x) =>
-	val u = lookup(env, x);
-	if (u == null) throw new TypeError("undefined: " + x);
-	else mgu(u.newInstance, t, s)
-
-      case Lam(x, e1) =>
-	val a, b = newTyvar();
-	val s1 = mgu(t, Arrow(a, b), s);
-	val env1 = Pair(x, TypeScheme(List(), a)) :: env;
-	tp(env1, e1, b, s1)
-
-      case App(e1, e2) =>
-	val a = newTyvar();
-	val s1 = tp(env, e1, Arrow(a, t), s);
-	tp(env, e2, a, s1)
-
-      case Let(x, e1, e2) =>
-	val a = newTyvar();
-	val s1 = tp(env, e1, a, s);
-	tp(Pair(x, gen(env, s1(a))) :: env, e2, t, s1)
-    }
-  }
-  var current: Term = null;
-
-  def typeOf(env: Env, e: Term): Type = {
-    val a = newTyvar();
-    tp(env, e, a, emptySubst)(a)
-  }
-}
-
-  object predefined {
-    val booleanType = Tycon("Boolean", List());
-    val intType = Tycon("Int", List());
-    def listType(t: Type) = Tycon("List", List(t));
-
-    private def gen(t: Type): typeInfer.TypeScheme = typeInfer.gen(List(), t);
-    private val a = typeInfer.newTyvar();
-    val env = List(
-/*
-      Pair("true", gen(booleanType)),
-      Pair("false", gen(booleanType)),
-      Pair("if", gen(Arrow(booleanType, Arrow(a, Arrow(a, a))))),
-      Pair("zero", gen(intType)),
-      Pair("succ", gen(Arrow(intType, intType))),
-      Pair("nil", gen(listType(a))),
-      Pair("cons", gen(Arrow(a, Arrow(listType(a), listType(a))))),
-      Pair("isEmpty", gen(Arrow(listType(a), booleanType))),
-      Pair("head", gen(Arrow(listType(a), a))),
-      Pair("tail", gen(Arrow(listType(a), listType(a)))),
-*/
-      Pair("fix", gen(Arrow(Arrow(a, a), a)))
-    )
-  }
-
-  abstract class MiniMLParsers extends CharParsers {
-
-    /** whitespace */
-    def whitespace = rep{chr(' ') ||| chr('\t') ||| chr('\n')};
-
-    /** A given character, possible preceded by whitespace */
-    def wschr(ch: char) = whitespace &&& chr(ch);
-
-    /** identifiers or keywords */
-    def id: Parser[String] =
-      for (
-        val c: char <- rep(chr(' ')) &&& chr(Character.isLetter);
-        val cs: List[char] <- rep(chr(Character.isLetterOrDigit))
-      ) yield (c :: cs).mkString("", "", "");
-
-    /** Non-keyword identifiers */
-    def ident: Parser[String] =
-      for (val s <- id; s != "let" && s != "in") yield s;
-
-    /** term = '\' ident '.' term | term1 {term1} | let ident "=" term in term */
-    def term: Parser[Term] =
-      ( for (
-          val _ <- wschr('\\');
-          val x <- ident;
-          val _ <- wschr('.');
-          val t <- term)
-        yield Lam(x, t): Term )
-      |||
-      ( for (
-          val letid <- id; letid == "let";
-          val x <- ident;
-          val _ <- wschr('=');
-          val t <- term;
-          val inid <- id; inid == "in";
-          val c <- term)
-        yield Let(x, t, c) )
-      |||
-      ( for (
-          val t <- term1;
-          val ts <- rep(term1))
-        yield (t /: ts)((f, arg) => App(f, arg)) );
-
-    /** term1 = ident | '(' term ')' */
-    def term1: Parser[Term] =
-      ( for (val s <- ident)
-        yield Var(s): Term )
-      |||
-      ( for (
-          val _ <- wschr('(');
-          val t <- term;
-          val _ <- wschr(')'))
-        yield t );
-
-    /** all = term ';' */
-    def all: Parser[Term] =
-      for (
-        val t <- term;
-        val _ <- wschr(';'))
-      yield t;
-  }
-
-  class ParseString(s: String) extends Parsers {
-    type intype = int;
-    val input = 0;
-    def any = new Parser[char] {
-      def apply(in: int): Parser[char]#Result =
-        if (in < s.length()) Some(Pair(s charAt in, in + 1)) else None;
-    }
-  }
-
-  def showType(e: Term): String =
-    try {
-      typeInfer.typeOf(predefined.env, e).toString();
-    } catch {
-      case typeInfer.TypeError(msg) =>
-	"\n cannot type: " + typeInfer.current +
-	"\n reason: " + msg;
-    }
-
-  def main(args: Array[String]): unit =
-    Console.println(
-      if (args.length == 1) {
-        val ps = new MiniMLParsers with ParseString(args(0));
-        ps.all(ps.input) match {
-          case Some(Pair(term, _)) =>
-            "" + term + ": " + showType(term)
-          case None =>
-	        "syntax error"
-        }
-      } else "usage: java examples.typeinf <expr-string>"
-    );
-
-}
-