More Helpful Error Messages - Added to Roadmap

[dougransom]

Some discussion at #2253.

I would like error messages suitable for a beginner, to more easily identify errors. It is pretty easy to get confused coming from another language and accidentally using # for a comment line or - or -> or : instead of :-. Not sure what would help.

There are may be runtime cases as well where more context could be provided (file/line # of a problematic predicate etc.)

[rotu]

When loading a file, I'd especially like to see the offending text printed out, maybe even which character.

Right now, the message is terse. It took me a while to even realize that :9 is the offending line number in the below error (it's not even the line where I omitted a comma; just the line containing the . ending the term).

> scryer-prolog error.pl
   error(syntax_error(incomplete_reduction),read_term/3:9).
?-

[UWN]

#302 would help to begin with.

[hurufu]

Indeed this is a reoccurring feature request: #2599, similarly I've started to add more warnings (#2602) to notify the user about possible issues with their code, but I don't have time and stamina to finish it.