Shell: Add support for $0,$1,...

Shell/Shell.cpp

@@ -333,6 +333,33 @@ RefPtr<AST::Value> Shell::lookup_local_variable(const String& name)
  if (auto* frame = find_frame_containing_local_variable(name))
  return frame->local_variables.get(name).value();
 
+ if (auto index = name.to_uint(); index.has_value())
+ return get_argument(index.value());
+
+ return nullptr;
+}
+
+RefPtr<AST::Value> Shell::get_argument(size_t index)
+{
+ if (index == 0)
+ return adopt(*new AST::StringValue(current_script));
+
+ --index;
+ if (auto argv = lookup_local_variable("ARGV")) {
+ if (argv->is_list_without_resolution()) {
+ AST::ListValue* list = static_cast<AST::ListValue*>(argv.ptr());
+ if (list->values().size() <= index)
+ return nullptr;
+
+ return list->values().at(index);
+ }
+
+ if (index != 0)
+ return nullptr;
+
+ return argv;
+ }
+
  return nullptr;
 }
 
@@ -750,6 +777,7 @@ NonnullRefPtrVector<Job> Shell::run_commands(Vector<AST::Command>& commands)
 
 bool Shell::run_file(const String& filename, bool explicitly_invoked)
 {
+ TemporaryChange script_change { current_script, filename };
  auto file_result = Core::File::open(filename, Core::File::ReadOnly);
  if (file_result.is_error()) {
  if (explicitly_invoked)

Shell/Shell.h

@@ -92,6 +92,7 @@ class Shell : public Core::Object {
  String resolve_path(String) const;
  String resolve_alias(const String&) const;
 
+ RefPtr<AST::Value> get_argument(size_t);
  RefPtr<AST::Value> lookup_local_variable(const String&);
  String local_variable_or(const String&, const String&);
  void set_local_variable(const String&, RefPtr<AST::Value>);
@@ -170,6 +171,8 @@ class Shell : public Core::Object {
  HashMap<u64, NonnullRefPtr<Job>> jobs;
  Vector<String, 256> cached_path;
 
+ String current_script;
+
  enum ShellEventType {
  ReadLine,
  };

Shell/main.cpp

@@ -209,6 +209,8 @@ int main(int argc, char** argv)
 
  parser.parse(argc, argv);
 
+ shell->current_script = argv[0];
+
  if (!skip_rc_files) {
  auto run_rc_file = [&](auto& name) {
  String file_path = name;