started to add proper errors

errors.js

@@ -0,0 +1,35 @@
+/*
+ * This file defines common error objects
+ * for reporting on syntax errors, type errors,
+ * and perhaps runtime exceptions although I have
+ * not thought about how that will work much
+ */
+
+var JLException = {
+  stxerror :
+    function () {
+      console.log("There was an error\n",
+                  "Line #",this.linenum,"\n",
+                  "Character #", this.charnum,"\n",
+                  this.errormessage);
+    },
+  type_error :
+    function () {
+      return;
+    }
+}
+
+function SyntaxError(linenum, charnum, message) {
+  this.linenum = linenum;
+  this.charnum = charnum;
+  this.errormessage = message;
+  return this;
+}
+
+function TypeError(linenum, charnum, token, message) {
+  this.linenum = linenum;
+  this.charnum = charnum;
+  this.errormessage = message;
+  this.token = token;
+  return this;
+}

parse.js

@@ -192,6 +192,9 @@ function parseLambda(tokens) {
 	return new typ.FuncT(parameters, body);
 }
 
+//function parseLet(tokens) {
+
+
 var invalidArguments = ["def", "comma", "right_paren", "right_square", "right_brace", "left_brace", "right_brace"];
 var validArgument = tool.compose(tool.not, makeChecker(invalidArguments));
 var validArgTypes = tool.compose(tool.not, makeChecker(["Definition"]));
@@ -298,9 +301,9 @@ function parse(tokens) {
     else
       return computeApp(tokens);
   }
-  /*else if (toktype === "let") {
+//  else if (toktype === "let") {
-    return parseLet(tokens);
+//    return parseLet(tokens);
-  }*/
+//  }
   else {
     throw "Error: Unexpected token: " + toktype;
   }
@@ -309,11 +312,17 @@ function parse(tokens) {
 var istr = fs.readFileSync('/dev/stdin').toString();
 function parseFull(tokenized) {
   var ast = new Array();
+  try {
     while (tokenized.length > 0) {
       var parsed = desugarer.desugar(parse(tokenized));
       ast.push(parsed);
     }
     return ast;
+  } catch (e) {
+    print("An exception occured, could not finish parsing");
+    print(e);
+    process.exit(1);
+  }
 }
 console.log(parseFull(tokenizer.tokenize(istr)).map(pprint.pprint).join("\n"));
 

representation.js

@@ -30,6 +30,7 @@ function LetExp(pairs) {
   this.val = tool.dict(pairs);
   return this;
 }
+LetExp.prototype = Expression;
 
 function UnaryOp(op, v) {
   this.exprType = "Unary";
@@ -37,6 +38,7 @@ function UnaryOp(op, v) {
   this.op = op;
   return this;
 }
+UnaryOp.prototype = Expression;
 
 function IntT(v) {
 	this.exprType = "Integer";

tokenize.js

@@ -308,9 +308,15 @@ function tokenize(tokstream) {
 }
 
 function tokenizeFull(input) {
+  try {
     return tokenize(input).reverse().filter(function(x) {
       return x[0] !== "whitespace";
     });
+  } catch (e) {
+    console.log("An error occured during tokenization");
+    console.log(e);
+    process.exit(1);
+  }
 }