mettalog Misleading Behavior When File Is Missing

[TeamSPoon]

When running mettalog with a missing .metta file, the program does not clearly indicate what it’s doing. It appears to hang, but in reality, it’s just waiting for input. The output lacks a newline and prompt clarity, making it non-obvious that the program is still running and accepting input.

For example, running:

mettalog missing-file.metta

Produces:

#(in #( : user #(load_metta_file &self missing-file.metta) ) #(error #(missing_exception #(load_metta &self missing-file.metta)) $10000))
|
|
|

Interrupting with Ctrl+C reveals the stack trace, but it’s clear that the program is waiting for input at this point.

Action (h for help) ? goals
     [57] [system] read_string(current_input, '\n', '\r', _1076, _1078)
     [56] [read_util] read_util:read_line_to_string(current_input, _1074)
     [55] [user] repl_read_next("\n\n\n", _930)
     [48] [user] repl_read_next(_930)
     [47] [user] repl_read(_896)
     [46] [system] catch(user:repl_read(_896), stream_error(_900, _902), user:(writeln(_902), throw(restart_reading)))
     [45] [user] repl4
     [44] [user] '<meta-call>'(user:(ttyflush, repl4, ttyflush))
     [43] [system] setup_call_cleanup(user:true, user:(ttyflush, repl4, ttyflush), user:notrace(prompt(_856, '|: ')))
     [41] [system] once(user:repl3)
     [40] [system] catch(user:once(repl3), restart_reading, user:true)
     [39] [system] ignore(user:catch(once(repl3), restart_reading, true))
     [38] [system] catch(user:ignore(catch(once(repl3), restart_reading, true)), give_up(_702), user:pp_m('red', gave_up(_702)))
     [37] [system] ignore(user:catch(ignore(catch(once(repl3), restart_reading, true)), give_up(_702), pp_m('red', gave_up(_702)))),
     ...

Steps to Reproduce:

1. Run the command mettalog missing-file.metta.
2. Observe that the program outputs an error message but does not flush the output or indicate that it’s ready for input.
3. Press Ctrl+C to confirm that the program is still running and waiting for input.

Expected Behavior:

• The program should flush the output, include a newline, and clearly display the prompt to indicate it is ready for input.
• A more user-friendly output might look like this:

#(in #( : user #(load_metta_file &self missing-file.metta) ) #(error #(missing_exception #(load_metta &self missing-file.metta)) $10000))
metta+>

Actual Behavior:
The output is confusing, with no indication that the program is waiting for input, leading to the impression that it’s hanging.

Additional Information:

• This issue makes it difficult for users to understand the program state, especially when handling errors.
• Adding a newline and flushing the output would significantly improve clarity.

Request:
Please update the program to:

1. Ensure output is flushed correctly.
2. Add a newline after error messages or other output.
3. Clearly display the prompt when waiting for input.

[TeamSPoon]

closing this for later..