Updated the Makefile, set debug option for the compiler, and fixed all the warnings generated by gcc with O2 optimization option for release builds.

Makefile

@@ -1,5 +1,5 @@
 CC = gcc
-CFLAGS=-Wall -DDEBUG
+CFLAGS=-g -Wall -DDEBUG
 SRCDIR=src
 OBJDIR=obj
 SRCS=$(wildcard $(SRCDIR)/*.c)
@@ -31,7 +31,7 @@ $(OBJDIR):
 .PHONY: test
 
 clean:
-	rm -r $(BINDIR)/* $(OBJDIR)/*
+	rm -rf $(BINDIR)/* $(OBJDIR)/*
 
 test:
 	$(BIN) test.lox

src/interpreter.c

@@ -14,7 +14,7 @@ Object* VisitBinaryExpression(Expr*);
 int IsTruthy(Object*);
 int IsEqual(Object*, Object*);
 int ConcatStringObject(Object*, const Object*);
-void CheckNumberOperand(TokenType, int, ...);
+void CheckNumberOperands(TokenType, int, ...);
 void PrintObject(Object*);
 
 void PrintObject(Object* o) {
@@ -70,54 +70,61 @@ Object* VisitBinaryExpression(Expr* expression) {
 
     switch(expression->expression.Binary.op->type) {
         case Greater:
+        CheckNumberOperands(expression->expression.Binary.op->type, 2, left, right);
         computed_value = left->value.number > right->value.number;
         FreeObject(left);
         FreeObject(right);
         return CreateObject(&computed_value, TRUE);
         //return left > right;
         case Greater_Equal:
+        CheckNumberOperands(expression->expression.Binary.op->type, 2, left, right);
         computed_value = left->value.number >= right->value.number;
         FreeObject(left);
         FreeObject(right);
         return CreateObject(&computed_value, TRUE);
         //return left >= right;
         case Less:
+        CheckNumberOperands(expression->expression.Binary.op->type, 2, left, right);
         computed_value = left->value.number < right->value.number;
         FreeObject(left);
         FreeObject(right);
         return CreateObject(&computed_value, TRUE);
         //return left < right;
         case Less_Equal:
+        CheckNumberOperands(expression->expression.Binary.op->type, 2, left, right);
         computed_value = left->value.number <= right->value.number;
         FreeObject(left);
         FreeObject(right);
         return CreateObject(&computed_value, TRUE);
         //return left <= right;
         case Bang_Equal:
+        CheckNumberOperands(expression->expression.Binary.op->type, 2, left, right);
         computed_value = !IsEqual(left, right);
         FreeObject(left);
         FreeObject(right);
         return CreateObject(&computed_value, TRUE);
         //return !IsEqual(left, right);
         case Equal_Equal:
+        CheckNumberOperands(expression->expression.Binary.op->type, 2, left, right);
         computed_value = IsEqual(left, right);
         FreeObject(left);
         FreeObject(right);
         return CreateObject(&computed_value, TRUE);
         //return IsEqual(left, right);
         case Minus:
-
+            CheckNumberOperands(expression->expression.Binary.op->type, 2, left, right);
             left->value.number -= right->value.number;
             FreeObject(right);
             return left;
         //return left - right;
         case Slash:
+            CheckNumberOperands(expression->expression.Binary.op->type, 2, left, right);
             left->value.number /= right->value.number;
             FreeObject(right);
             return left;
         //return *((double*)left) / *((double*)right);
         case Star:
-            printf("%f * %f = %f\n", left->value.number, right->value.number, left->value.number * right->value.number);
+            CheckNumberOperands(expression->expression.Binary.op->type, 2, left, right);
             left->value.number *= right->value.number;
             FreeObject(right);
             return left;
@@ -158,7 +165,7 @@ Object* VisitUnaryExpression(Expr* expression) {
 
     switch (expression->expression.Unary.op->type) {
         case Minus:
-        CheckNumberOperand(expression->expression.Unary.op->type, right);//This needs to "throw" if the function fails.
+        CheckNumberOperands(expression->expression.Unary.op->type, 1, right);//This needs to "throw" if the function fails.
         computed_value = -right->value.number;
         FreeObject(right);
         c = CreateObject(&computed_value, Number);
@@ -222,11 +229,16 @@ Object* CreateObject(const void* value, TokenType type) {
         break;
         default:
         if (value) {
-            int length = strlen(value);
+            unsigned int length = strlen(value);
             object->instance = INS_STRING;
             object->value.string = calloc(length + 1, sizeof(char));
+
+            if (!object->value.string) {
+                fprintf(stderr, "Faild to calloc %u bytes for a new string Object. %s.\n", length + 1, strerror(errno));
+                return NULL;
+            }
             
-            strncpy(object->value.string, value, length);
+            memcpy(object->value.string, value, length);
         } else object->instance = INS_NULL; //TODO: this is most likely an error, but we'll ignore that for now.
     }
 
@@ -284,7 +296,7 @@ int IsEqual(Object* a, Object* b) {
     return 0;
 }
 
-void CheckNumberOperand(TokenType operator, int operandCount, ...) {
+void CheckNumberOperands(TokenType operator, int operandCount, ...) {
     va_list list;
     va_start(list, operandCount);
 

src/token.c

@@ -33,7 +33,7 @@ Token* CreateToken(const char* lexeme, void* literal, int line, TokenType type)
         const char* mapping_result = GetLexemeMapping(type);
         
         if (!mapping_result) {
-            fprintf(stderr, "Failed to get the mapping for %s\n", lexeme);
+            fprintf(stderr, "Failed to get the mapping for TokenType value %d.\n", type);
             free(token);
             return NULL;
         }