Some declaration guards

source/interpreter.c

@@ -311,6 +311,9 @@ static bool execVarDecl(Interpreter* interpreter, bool lng) {
 	}
 
 	if (!setScopeVariable(interpreter->scope, identifier, parseIdentifierToValue(interpreter, popLiteralArray(&interpreter->stack)) )) {
+		printf("Incorrect type assigned to variable \"");
+		printLiteral(identifier);
+		printf("\"\n");
 		return false;
 	}
 
@@ -328,7 +331,19 @@ static bool execVarAssign(Interpreter* interpreter) {
 		return false;
 	}
 
-	setScopeVariable(interpreter->scope, lhs, rhs);
+	if (!isDelcaredScopeVariable(interpreter->scope, lhs)) {
+		printf("Undeclared variable \"");;
+		printLiteral(lhs);
+		printf("\"\n");
+		return false;
+	}
+
+	if (!setScopeVariable(interpreter->scope, lhs, rhs)) {
+		printf("Incorrect type assigned to variable \"");
+		printLiteral(lhs);
+		printf("\"\n");
+		return false;
+	}
 
 	return true;
 }

source/parser.c

@@ -763,8 +763,10 @@ static void expressionStmt(Parser* parser, Node** nodeHandle) {
 	Node* ptr = NULL;
 	expression(parser, &ptr);
 
+	if (ptr != NULL) {
 		**nodeHandle = *ptr;
 		FREE(Node, ptr); //BUGFIX: this thread of execution is nuts
+	}
 
 	consume(parser, TOKEN_SEMICOLON, "Expected ';' at the end of expression statement");
 }

source/scope.c

@@ -59,7 +59,11 @@ bool declareScopeVariable(Scope* scope, Literal key, Literal type) {
 	return true;
 }
 
-//return false if undefined
+bool isDelcaredScopeVariable(Scope* scope, Literal key) {
+	return existsLiteralDictionary(&scope->variables, key);
+}
+
+//return false if undefined, or can't be assigned
 bool setScopeVariable(Scope* scope, Literal key, Literal value) {
 	//dead end
 	if (scope == NULL) {

source/scope.h

@@ -14,6 +14,7 @@ Scope* popScope(Scope* scope);
 
 //returns false if error
 bool declareScopeVariable(Scope* scope, Literal key, Literal type);
+bool isDelcaredScopeVariable(Scope* scope, Literal key);
 
 //return false if undefined
 bool setScopeVariable(Scope* scope, Literal key, Literal value);