diff --git a/src/Makefile b/src/Makefile
index 95badf3..280a9b6 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -6,3 +6,6 @@ debug:
 
 phrase:
 	gcc -g -O0 -o pebblisp -D STANDALONE -D DEBUG -D NO_REPL pebblisp.c tokens.c object.c
+
+run:
+	./pebblisp
diff --git a/src/object.h b/src/object.h
index 80470c3..f2956ae 100644
--- a/src/object.h
+++ b/src/object.h
@@ -6,6 +6,7 @@
 #define MAX_ENV_ELM 15  // 50
 
 enum errorCode {
+    MISMATCHED_PARENS,
     BAD_LIST_OF_SYMBOL_STRINGS,
     TYPE_LIST_NOT_CAUGHT,
     NULL_ENV,
@@ -21,6 +22,7 @@ enum errorCode {
 
 //#ifdef STANDALONE
 static const char *errorText[] = {
+    "MISMATCHED_PARENS",
     "BAD_LIST_OF_SYMBOL_STRINGS",
     "TYPE_LIST_NOT_CAUGHT",
     "NULL_ENV",
diff --git a/src/pebblisp.c b/src/pebblisp.c
index 4fe24cb..3578ab5 100644
--- a/src/pebblisp.c
+++ b/src/pebblisp.c
@@ -22,6 +22,8 @@ void debugSlice(struct Slice *s)
     printd("Debug Slice\n    text:'");
     for(int i = 0; i < s->length; i++) {
         printd("%c", s->text[i]);
+        if(s->text[i] == '\0')
+            printd("NULLCHAR\n");
     }
     printd("'\n");
     printd("  length: %d\n", s->length);
@@ -61,7 +63,7 @@ Result parse(struct Slice *slices)
     if(token->text[0] == '(') {
         // todo check for null rest
         return readSeq(rest);
-    } else { // todo error on closed paren
+    } else { // todo error on missing close paren
         return result(parseAtom(token), rest);
     }
 }
@@ -109,6 +111,7 @@ Object evalDefArgs(const Object *arg_forms, struct Environment *env)
     const Object *first_form = &arg_forms[0];
     const char *name = first_form->name;
 
+    // Immediately adding the function to the env might allow recursion?
     Object second_eval = eval(first_form->forward, env);
 
     addToEnv(env, name, second_eval);
@@ -125,8 +128,8 @@ Object evalIfArgs(const Object *arg_forms, struct Environment *env)
 
 Object evalLambdaArgs(const Object *arg_forms)
 {
-                         // params             // body
-    return constructLambda(arg_forms, arg_forms->forward);
+                         // params               // body
+    return constructLambda(arg_forms, arg_forms? arg_forms->forward : NULL);
 }
 
 Object evalMapArgs(const Object *arg_forms, struct Environment *env)
@@ -137,14 +140,12 @@ Object evalMapArgs(const Object *arg_forms, struct Environment *env)
     const Object lambda = eval(&arg_forms[0], env);
     Object *oldList = (&arg_forms[0])->forward;
 
-    if(lambda.type != TYPE_LAMBDA || oldList->type != TYPE_LIST) {
+    if(lambda.type != TYPE_LAMBDA || oldList->type != TYPE_LIST)
         return errorObject(BAD_TYPE);
-    }
 
     Object list = listObject();
 
-    int i = 0;
-    Object *oldElement = oldList->list;
+    const Object *oldElement = oldList->list;
     while(oldElement != NULL) {
         // Create a new list for each element in the list,
         // since lambda evaluation looks for a list
@@ -152,7 +153,6 @@ Object evalMapArgs(const Object *arg_forms, struct Environment *env)
         Object listBack[1] = {*oldElement};
         listBack[0].forward = NULL;
         tempList.list = listBack;
-        printObj(&tempList);
 
         struct Environment newEnv = 
                 envForLambda(&lambda.lambda->params, &tempList, env);
@@ -192,7 +192,6 @@ struct Environment envForLambda(const Object *params, const Object *arg_forms,
         const char *n = itemAt(params, i)->name;
         addToEnv(&env, n, eval(&arg_forms[i], outer)); // May not need eval?
             // SHOULD BE `vs` not arg_forms???
-
     } // Something is segfaulting, anyway
     // env.strings[length] = NULL;
 
@@ -432,6 +431,8 @@ struct Environment defaultEnv() {
 Object parseEval(const char *input, struct Environment *env)
 {
     struct Slice *tokens = nf_tokenize(input);
+    if(!tokens)
+        return errorObject(MISMATCHED_PARENS);
 #ifdef DEBUG
     struct Slice *debug = tokens;
     if(debug) {
diff --git a/src/tokens.c b/src/tokens.c
index 5bbfac1..c8eb88d 100644
--- a/src/tokens.c
+++ b/src/tokens.c
@@ -63,6 +63,10 @@ struct Slice *nf_tokenize(const char *input)
             parens++;
         } else if (input[i] == ')') {
             parens--;
+            if(parens < 0) {
+                free(slices);
+                return NULL;
+            }
         }
 
         if(isSingle(input[i])) {