Shell: Do not treat the ending newline as part of a comment

This allows the parser to finally parse the entire source into a single
AST.
As a result of allowing comments inside sequences, Sequence is also
marked as would_execute if its left or right node would.

Shell/AST.cpp

@@ -556,7 +556,7 @@ void Comment::dump(int level) const
 
 RefPtr<Value> Comment::run(RefPtr<Shell>)
 {
- return create<StringValue>("");
+ return create<ListValue>({});
 }
 
 void Comment::highlight_in_editor(Line::Editor& editor, Shell&, HighlightMetadata)
@@ -1229,7 +1229,27 @@ void Sequence::dump(int level) const
 
 RefPtr<Value> Sequence::run(RefPtr<Shell> shell)
 {
+ // If we are to return a job, block on the left one then return the right one.
+ if (would_execute()) {
+ RefPtr<AST::Node> execute_node = create<AST::Execute>(m_left->position(), m_left);
+ auto left_job = execute_node->run(shell);
+ ASSERT(left_job->is_job());
+ shell->block_on_job(static_cast<JobValue*>(left_job.ptr())->job());
+
+ if (m_right->would_execute())
+ return m_right->run(shell);
+
+ execute_node = create<AST::Execute>(m_right->position(), m_right);
+ return execute_node->run(shell);
+ }
  auto left = m_left->run(shell)->resolve_as_commands(shell);
+ // This could happen if a comment is next to a command.
+ if (left.size() == 1) {
+ auto& command = left.first();
+ if (command.argv.is_empty() && command.redirections.is_empty())
+ return m_right->run(shell);
+ }
+
  auto right = m_right->run(shell)->resolve_as_commands(shell);
 
  Vector<Command> commands;

Shell/AST.h

@@ -699,6 +699,7 @@ class Sequence final : public Node {
  virtual HitTestResult hit_test_position(size_t) override;
  virtual String class_name() const override { return "Sequence"; }
  virtual bool is_list() const override { return true; }
+ virtual bool would_execute() const override { return m_left->would_execute() || m_right->would_execute(); }
 
  RefPtr<Node> m_left;
  RefPtr<Node> m_right;

Shell/Parser.cpp

@@ -717,9 +717,6 @@ RefPtr<AST::Node> Parser::parse_comment()
 
  consume();
  auto text = consume_while(is_not('\n'));
- if (peek() == '\n')
- consume();
-
  return create<AST::Comment>(move(text)); // Comment
 }
 

Shell/Shell.cpp

@@ -316,9 +316,6 @@ int Shell::run_command(const StringView& cmd)
  if (cmd.is_empty())
  return 0;
 
- if (cmd.starts_with("#"))
- return 0;
-
  auto command = Parser(cmd).parse();
 
  if (!command)
@@ -505,6 +502,8 @@ bool Shell::run_file(const String& filename, bool explicitly_invoked)
  if (file_result.is_error()) {
  if (explicitly_invoked)
  fprintf(stderr, "Failed to open %s: %s\n", filename.characters(), file_result.error().characters());
+ else
+ dbg() << "open() failed for '" << filename << "' with " << file_result.error();
  return false;
  }
  auto file = file_result.value();