#t and #f added to language, datetime fixes

ml.cpp

@@ -51,6 +51,7 @@
 #define INT_TYPE "int"
 #define FLOAT_TYPE "float"
 #define NIL_TYPE "nil"
+#define TRUE_TYPE "#t"
 #define FUNCTION_TYPE "function"
 #define ATOM_TYPE "atom"
 #define QUOTE_TYPE "quote"
@@ -70,11 +71,8 @@ MlValue::MlValue(long i) : type(INT) { stack_data.i = i; }
 MlValue::MlValue(double f) : type(FLOAT) { stack_data.f = f; }
 
 MlValue::MlValue(bool b) {
-	if (b) {
-		type = INT;
-		stack_data.i = 1;
-	}
-	else { type = NIL; }
+	if (b) type = TRUE;
+	else type = NIL;
 }
 
 MlValue::MlValue(const std::vector<MlValue> &list) : type(LIST), list(list) {}
@@ -186,7 +184,7 @@ bool MlValue::is_list() const {
 }
 
 bool MlValue::as_bool() const {
-	return type != NIL && *this != MlValue(0l);        // TODO remove 0 as false
+	return type != NIL;
 }
 
 long MlValue::as_int() const {
@@ -313,6 +311,8 @@ bool MlValue::operator==(MlValue other) const {
 			return list[0] == other.list[0];
 		case NIL:
 			return other.type == NIL;
+		case TRUE:
+			return other.type == TRUE;
 		default:
 			return true;
 	}
@@ -515,6 +515,8 @@ std::string MlValue::get_type_name() const {
 			return FUNCTION_TYPE;
 		case NIL:
 			return NIL_TYPE;
+		case TRUE:
+			return TRUE_TYPE;
 		default:
 			// This should never be reached.
 			throw MlError(*this, MlEnvironment(), INTERNAL_ERROR);
@@ -550,6 +552,8 @@ std::string MlValue::display() const {
 			return "<" + str + " at " + std::to_string(long(stack_data.b)) + ">";
 		case NIL:
 			return "nil";
+		case TRUE:
+			return "#t";
 		default:
 			// This should never be reached.
 			throw MlError(*this, MlEnvironment(), INTERNAL_ERROR);
@@ -589,6 +593,8 @@ std::string MlValue::debug() const {
 			return "<" + str + " at " + std::to_string(long(stack_data.b)) + ">";
 		case NIL:
 			return "nil";
+		case TRUE:
+			return "#t";
 		default:
 			// This should never be reached.
 			throw MlError(*this, MlEnvironment(), INTERNAL_ERROR);
@@ -840,6 +846,10 @@ MlValue parse(std::string &s, int &ptr) {
 		skip_whitespace(s, ptr);
 		if (x == "nil")
 			return MlValue::nil();
+		else if(x == "#f")
+			return MlValue(false);
+		else if (x == "#t")
+			return MlValue(true);
 		else
 			return MlValue::atom(x);
 
@@ -872,6 +882,9 @@ std::vector<MlValue> parse(std::string s) {
 MlValue run(const std::string &code, MlEnvironment &env) {
 	// Parse the code
 	std::vector<MlValue> parsed = parse(code);
+	if (parsed.empty())
+		return MlValue::nil();
+
 	// Iterate over the expressions and evaluate them
 	// in this environment.
 	for (size_t i = 0; i < parsed.size() - 1; i++)
@@ -1033,7 +1046,7 @@ MlValue do_and(std::vector<MlValue> args, MlEnvironment &env) {
 	for (size_t i = 0; i < args.size(); i++)
 		if (!args[i].eval(env).as_bool()) return MlValue::nil();
 
-	return MlValue{1l};
+	return MlValue{true};
 }
 
 // Evaluate logical or on a list of expressions (SPECIAL FORM)
@@ -1042,7 +1055,7 @@ MlValue do_or(std::vector<MlValue> args, MlEnvironment &env) {
 		throw MlError(MlValue("or", do_or), env, TOO_FEW_ARGS);
 
 	for (size_t i = 0; i < args.size(); i++)
-		if (args[i].eval(env).as_bool()) return MlValue{1l};
+		if (args[i].eval(env).as_bool()) return MlValue{true};
 
 	return MlValue::nil();
 }
@@ -1153,7 +1166,7 @@ MlValue write_file(std::vector<MlValue> args, MlEnvironment &env) {
 	if (args.size() != 2)
 		throw MlError(MlValue("write-file", write_file), env, args.size() > 2 ? TOO_MANY_ARGS : TOO_FEW_ARGS);
 
-	return MlValue((long) write_file_contents(args[0].as_string(), args[1].as_string()));
+	return MlValue(write_file_contents(args[0].as_string(), args[1].as_string()));
 }
 
 // Read URL to (code content)
@@ -1210,6 +1223,16 @@ MlValue get_universal_time(std::vector<MlValue> args, MlEnvironment &env) {
 	return MlValue(now());
 }
 
+// Get offsets in secs between local timezone and gmt
+MlValue get_localtime_offset(std::vector<MlValue> args, MlEnvironment &env) {
+	eval_args(args, env);
+
+	if (args.size() != 0)
+		throw MlError(MlValue("get-localtime-offset", get_localtime_offset), env, TOO_MANY_ARGS);
+
+	return MlValue(get_gmt_localtime_offset());
+}
+
 // Converts date to formated string.
 MlValue date_to_str(std::vector<MlValue> args, MlEnvironment &env) {
 	eval_args(args, env);
@@ -1624,7 +1647,7 @@ MlValue string_regex(std::vector<MlValue> args, MlEnvironment &env) {
 	if (args.size() != 2)                // if (args.size() < 2 || args.size() > 3)
 		throw MlError(MlValue("string-regex?", string_regex), env, args.size() > 2 ? TOO_MANY_ARGS : TOO_FEW_ARGS);
 
-	return MlValue((long) regexp_search(args[0].as_string(), args[1].as_string()));
+	return MlValue(regexp_search(args[0].as_string(), args[1].as_string()));
 }
 
 // Splits string by regexp and returns list containing splited parts
@@ -2042,6 +2065,7 @@ MlValue MlEnvironment::get(const std::string &name) const {
 
 	// Datetime operations
 	if (name == "get-universal-time") return MlValue("get-universal-time", builtin::get_universal_time);
+	if (name == "get-localtime-offset") return MlValue("get-localtime-offset", builtin::get_localtime_offset);
 	if (name == "date-to-str") return MlValue("date-to-str", builtin::date_to_str);
 	if (name == "str-to-date") return MlValue("str-to-date", builtin::str_to_date);
 	if (name == "date-add") return MlValue("date-add", builtin::date_add);