refactor(AST): improve function declaration AST node

Change p_name to be of type std::string instead of furc::token.

furc/src/ast.cpp

@@ -118,7 +118,7 @@ void function_declaration_node::accept(visitor& visitor) const {
 }
 
 std::ostream& function_declaration_node::print(std::ostream& os) const {
-    return os << "function " << p_name->string << " declaration";
+    return os << "function " << p_name << " declaration";
 }
 
 bool function_declaration_node::equal(const node& rhs) const {
@@ -135,7 +135,7 @@ std::ostream& function_definition_node::print(std::ostream& os) const {
     if (m_body.has_value()) {
         for (const auto& entry : m_body->statements)
             os << entry << '\n';
-        return os << m_body->end << ": " << p_name->string << " end";
+        return os << m_body->end << ": " << p_name << " end";
     }
     return os << m_body.error();
 }

furc/src/front/ir_generator.cpp

@@ -5,6 +5,7 @@
 #include "furc/ast/literal.hpp"     // IWYU pragma: keep
 #include "furc/ast/statement.hpp"   // IWYU pragma: keep
 
+#include <cassert>
 #include <iostream>
 
 namespace furc::front {
@@ -14,7 +15,7 @@ namespace ir = furlang::ir;
 }
 
 void ir_generator::visit(const ast::function_definition_node& funcDef) {
-    m_currentFunction = std::make_unique<furlang::ir::function>(std::string(funcDef.name()->string));
+    m_currentFunction = std::make_unique<furlang::ir::function>(std::string(funcDef.name()));
 
     push_block();
     if (funcDef.body().has_error()) {

furc/src/front/parser.cpp

@@ -37,7 +37,7 @@ ast::program_node_r parser::parse() & {
         program->push(std::move(parse_declaration()));
     }
 
-    return program;
+    return std::move(program);
 }
 
 ast::declaration_node_r parser::parse_declaration() {
@@ -61,11 +61,13 @@ ast::declaration_node_r parser::parse_declaration() {
             case token_t::LBrace: {
                 ast::body_r body = parse_body();
                 if (body.has_error()) return ast::declaration_node_r(ast::error{ body.error().location });
-                return m_arena.allocate_shared<ast::function_definition_node>(first->location, *name, std::move(body));
+                return m_arena.allocate_shared<ast::function_definition_node>(first->location,
+                    name->value.string,
+                    std::move(body));
             }
             case token_t::Semicolon: {
                 m_peekBuffer.clear();
-                return m_arena.allocate_shared<ast::function_declaration_node>(first->location, *name);
+                return m_arena.allocate_shared<ast::function_declaration_node>(first->location, name->value.string);
             }
             default: return ast::declaration_node_r(ast::error{ tok->location });
             }