X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?a=blobdiff_plain;f=lambda.js;fp=lambda.js;h=0000000000000000000000000000000000000000;hb=6dc18a4ae23b84aeee4456c3f39a944109b5c68f;hp=4b684f4eeb22d9ff3da97828003fa732d5fdcd16;hpb=3a5bbeb0ce1de37b0203e7c0efc2062608a9827c;p=lambda.git

diff --git a/lambda.js b/lambda.js
deleted file mode 100644
index 4b684f4e..00000000
--- a/lambda.js
+++ /dev/null
@@ -1,170 +0,0 @@
-// Basic data structure, essentially a LISP/Scheme-like cons
-// pre-terminal nodes are expected to be of the form new cons(null, "string")
-function cons(car, cdr) {
-  this.car = car;
-  this.cdr = cdr;
-}
-
-// takes a stack of symbols, returns a pair: a tree and the remaining symbols
-function fold(split) {
-  if (split == null) return (new cons (null, null));
-  if (split.length == 0) return (new cons (null, null));
-  var token = split.shift();
-  if (token == ")") return (new cons (null, split));
-  var next = fold(split);
-  if (token == "(") {
-    var nextnext = fold(next.cdr);
-    return (new cons ((new cons (next.car, nextnext.car)),
-                      nextnext.cdr));
-  }
-  return (new cons ((new cons ((new cons (null, token)),
-                               next.car)),
-                    next.cdr))
-}
-
-// substitute arg in for v in tree
-function sub(tree, v, arg) {
-  if (tree == null) return (null);
-  if (tree.car == null) if (tree.cdr == v) return (arg);
-  if (tree.car == null) return (tree);
-
-  // perform alpha reduction to prevent variable collision
-  if (isBindingForm(tree)) 
-    return (new cons (tree.car, 
-                      sub(sub(tree.cdr,         // inner sub = alpha reduc.
-                              tree.cdr.car.cdr, 
-                              fresh(tree.cdr.car.cdr)),
-                          v,
-                          arg)));
-
-  return (new cons ((sub (tree.car, v, arg)),
-                    (sub (tree.cdr, v, arg))))
-}
-
-// Guaranteed unique for each call as long as string is not empty.
-var i = 0;
-function fresh(string) {
-  i = i+1;
-  if (typeof(string) != "string") return (string);
-  return (new cons (null,  
-                    string.substring(0,1) + (i).toString()));
-}
-
-// Keep reducing until there is no more change
-function fixedPoint (tree) {
-  var t2 = reduce(tree);
-  if (treeToString(tree) == treeToString(t2)) return (tree);
-  return (fixedPoint (t2));
-}
-
-// Reduce all the arguments, then try to do beta conversion on the whole
-function reduce(tree) {
-  if (tree == null) return (tree);
-  if (typeof(tree) == "string") return (tree);
-  return (convert (new cons (reduce (tree.car), mapReduce (tree.cdr))));
-}
-
-// Reduce all the arguments in a list
-function mapReduce(tree) {
-  if (tree == null) return (tree);
-  if (tree.car == null) return (tree);
-  return (new cons (reduce (tree.car), mapReduce(tree.cdr )));
-}
-
-// If the list is of the form ((lambda var body) arg), do beta reduc.
-function convert(tree) {
-    if (isLet(tree)) {
-      return (sub(tree.cdr.car, tree.car.cdr.car.cdr, tree.car.cdr.cdr.car));}
-    else 
-      if (isConvertable(tree)) {
-        return (sub(tree.car.cdr.cdr.car, tree.car.cdr.car.cdr, tree.cdr.car));}
-      else return(tree);
-} 
-
-// Is of form ((let var arg) body)?
-function isLet(tree) {
-  if (tree == null) return (false);
-  if (!(isBindingForm(tree.car))) return (false);
-  if (tree.car.car.cdr != "let") return (false);
-  if (tree.cdr == null) return (false);
-  if (tree.cdr.car == null) return (false);
-  return(true);
-}  
-
-// Is of form ((lambda var body) arg)?
-function isConvertable(tree) {
-  if (tree == null) return (false);
-  if (!(isBindingForm(tree.car))) return (false);
-  if (tree.car.car.cdr != "lambda") return (false);
-  if (tree.cdr == null) return (false);
-  if (tree.cdr.car == null) return (false);
-  return(true);
-}  
-
-// Is of form (lambda var body)?
-function isBindingForm(tree) {
-  if (tree == null) return (false);
-  if (tree.car == null) return (false);
-  if (tree.car.car != null) return (false);
-  if ((tree.car.cdr != "lambda") 
-      && (tree.car.cdr != "let")
-      && (tree.car.cdr != "exists")
-      && (tree.car.cdr != "forall")
-      && (tree.car.cdr != "\u03BB")
-      && (tree.car.cdr != "\u2200")
-      && (tree.car.cdr != "\u2203")
-     )
-    return (false);
-  if (tree.car.cdr == null) return (false);
-  if (tree.cdr.car == null) return (false);
-  if (tree.cdr.car.car != null) return (false);
-  if (tree.cdr.cdr == null) return (false);
-  return (true);
-}
-
-function treeToString(tree) {
-  if (tree == null) return ("")
-  if (tree.car == null) return (tree.cdr)
-  if ((tree.car).car == null) 
-    return (treeToString(tree.car) + " " + treeToString(tree.cdr))
-  return ("(" + treeToString(tree.car) + ")" + treeToString(tree.cdr))
-}
-
-// use this instead of treeToString if you want to see the full structure
-function treeToStringRaw(tree) {
-  if (tree == null) return ("@")
-  if (typeof(tree) == "string") return (tree);
-  return ("(" + treeToStringRaw(tree.car) + "." + 
-                treeToStringRaw(tree.cdr) + ")")
-}
-
-// Make sure each paren will count as a separate token
-function stringToTree(input) {
-  input = input.replace(/let/g, " ( ( let ");
-  input = input.replace(/=/g, " ");
-  input = input.replace(/in/g, " ) ");
-  input = input.replace(/\(/g, " ( ");
-  input = input.replace(/\)/g, " ) ");
-  input = input.replace(/\^/g, " ^ ");
-  input = input.replace(/[\\]/g, " lambda ");
-  input = input.replace(/\u03BB/g, "lambda");
-  return ((fold(input.split(/[ \f\n\r\t\v]+/))).car)
-}
-
-// Adjust spaces to print pretty
-function formatTree(tree) {
-  output = treeToString (tree);
-  output = output.replace(/^[ \f\n\r\t\v]+/, "");
-  output = output.replace(/[ \f\n\r\t\v]+$/, "");
-  output = output.replace(/[ \f\n\r\t\v]+\)/g, ")");
-  output = output.replace(/\)([^)(])/g, ") $1");
-//  output = output.replace(/lambda/g, "\u03BB");
-//  output = output.replace(/exists/g, "\u2203");
-//  output = output.replace(/forall/g, "\u2200");
-  return (output)
-}
-
-function mytry(form) { 
-  i = 0;
-  form.result.value = formatTree(fixedPoint(stringToTree(form.input.value)));
-}