Add default constructor to handle

Signed-off-by: CHatingPython <chatingpython@gmail.com>

furc/src/ast.cpp

@@ -0,0 +1,45 @@
+#include "furc/ast/declaration.hpp"
+#include "furc/ast/literal.hpp"
+#include "furc/ast/node.hpp"
+#include "furc/ast/program.hpp"
+#include "furc/ast/statement.hpp"
+
+#include <ostream>
+
+namespace furc::ast {
+
+std::ostream& integer_literal_node::print(std::ostream& os) const {
+    if (m_value.has_error()) return os << m_value.error();
+    return os << "integer literal (" << *m_value << ")";
+}
+
+std::ostream& function_declarartion_node::print(std::ostream& os) const {
+    return os << "function " << m_name->string << " declaration";
+}
+
+std::ostream& function_definition_node::print(std::ostream& os) const {
+    function_declarartion_node::print(os);
+    os << ':';
+    if (m_body.present()) {
+        for (const auto& entry : m_body->statements)
+            os << '\n' << entry;
+        return os << '\n' << m_body->end << ": " << m_name->string << " end";
+    }
+    return os << m_body.error(); // error
+}
+
+std::ostream& return_statement_node::print(std::ostream& os) const {
+    os << "return statement";
+    if (m_value.present()) return os << " (" << *m_value << ')';
+    return os;
+}
+
+std::ostream& program_node::print(std::ostream& os) const {
+    os << "program:";
+    for (const auto& handle : m_declarations) {
+        os << '\n' << handle;
+    }
+    return os;
+}
+
+} // namespace furc::ast

furc/src/front/parser.cpp

@@ -93,11 +93,16 @@ ast::node_handle<ast::statement_node> parser::parse_statement() {
     if (tok.has_error()) return tok;
     switch (tok->type) {
     case token_t::Keyword: {
-        next_token();
-        auto err = eat_token(token_t::Semicolon);
-        if (err.has_error()) return err;
+        auto tok = next_token();
+        if (peek_token()->type == token_t::Semicolon) {
+            next_token();
+            return ast::node_handle<ast::return_statement_node>{ tok.location(), m_arena };
+        }
 
-        return ast::node_handle<ast::return_statement_node>{ tok.location(), m_arena };
+        auto value = parse_expression();
+        auto err   = eat_token(token_t::Semicolon);
+        if (err.has_error()) return err;
+        return ast::node_handle<ast::return_statement_node>{ tok.location(), m_arena, std::move(value) };
     }
     default: break;
     }

furc/src/main.cpp

@@ -5,7 +5,7 @@
 #include <iostream>
 
 int main(void) {
-    furc::front::parser parser("<TEMP>", "func main() {\n    return;\n}");
+    furc::front::parser parser("<TEMP>", "func main() {\n    return 67;return \"uwu\";\n}");
     std::cout << parser.parse() << '\n';
 
     return 0;