started on the desugarer

desugar.js

@@ -0,0 +1,11 @@
+/*
+ * This module takes a parse tree in a surface format
+ * and transforms it into the "core" language which is
+ * much simpler and easier to type-check, optimize, and evaluate
+ */
+
+var typ = require("./representation.js");
+
+// Lists get desugared to nested function calls
+// i.e. (cons (cons (cons ...)))
+function desugarList(lst) {

parse.js

@@ -1,3 +1,5 @@
+#! /usr/bin/node
+
 var typ = require("./representation.js");
 var tool = require("./tools.js");
 
@@ -174,7 +176,12 @@ function parseDef(tokens) {
 		return undefined;
 	}
 	else {
-		return new typ.Def(parse(tokens), parse(tokens));
+    var identifier = parse(tokens);
+    if (!notFollowedBy(tokens, ["def", "comma", "left_paren", "arrow", "right_brace", "right_square"])) {
+      console.log("Error: def " + identifier.val + " must not be followed by " + fst(tokens)[0]);
+      return;
+    }
+		return new typ.Def(identifier, parse(tokens));
 	}
  }
 
@@ -251,8 +258,16 @@ function parse(tokens) {
 		return checkParse(parseDef(tokens));
 	else if (toktype === "ifexp")
 		return checkParse(parseIf(tokens));
-	else if (toktype === "left_paren")
+	else if (toktype === "left_paren") {
+		if (fst(tokens)[0] === "lambda") {
+      tokens.pop();
+      var parsed = checkParse(parseLambda(tokens));
+      tokens.pop();
+      return parsed;
+    }
+    else
       return computeApp(tokens);
+  }
   else {
     console.log("Unexpected token: " + toktype);
     process.exit(code=1);
@@ -334,8 +349,6 @@ function parseInfix(tokens, minPrec, lhs) {
 		//remove the operator token
 		var rhs = parseInfix(tokens, nextMinPrec);
 		lhs = typ.makeApp(op, [lhs, rhs]);
-
-
 	}
 	return lhs;
 }

representation.js

@@ -58,7 +58,7 @@ BoolT.prototype = Expression;
 function ListT(x, xs) {
 	this.x = x;
 	this.rest = xs;
-	this.val = [x,xs];
+	this.val = xs;
 	this.exprType = "List";
 	return this;
 }
@@ -112,7 +112,7 @@ function Def(ident, exp) {
 function If(condition, thenexp, elseexp) {
 	this.condition = condition;
 	this.thenexp = thenexp;
-	if (elseexp)
+if (elseexp)
 		this.elseexp = elseexp;
 	this.exprType = "If";
 	return this;
@@ -139,8 +139,6 @@ function makeApp(name, parameters) {
 
 }
 
-OPTable = {"+" : makeBin("+")};
-
 OPInfo = {"+" : [2, "Left"],
 		  "-" : [2, "Left"],
 		  "*" : [3, "Left"],