Provide an alternative format for error/warning messages; eg: file:line:col instead of file(line, col)

[ziotom78]

Currently the Nimrod compiler produces error messages using a format string similar to the one used by Free Pascal, i.e., with the line and column numbers enclosed in parentheses:

  test.nim(5, 0) Error: invalid indentation

However, this kind of syntax is not recognized by Emacs. When you run the compiler using Emacs' compile function, you cannot highlight the errors and move from one to another using next-error, because such functions expect something in the form

  test.nim:5:0: Error: invalid indentation

(see http://www.gnu.org/prep/standards/html_node/Errors.html#Errors).

The Free Pascal compiler fpc solves this by accepting the (scarcely documented) command-line flag -vr ("Rhide/GCC compatibility mode"):

  $ fpc test.pas
  ...
  test.pas(4,6) Error: Identifier not found "X"
  ...
  $ fpc -vr test.pas
  ...
  test.pas:4: error 6: Error: Identifier not found "X"
  ...

which is not perfect but at least allows Emacs to find the right line in the source code.

Since I am an avid Emacs user, would somebody be interested in having this feature implemented in Nimrod? I can fork the repository and try to implement it by myself, but first I would know if it is sensible to add such a patch, and if there is anything I must be aware of.

[gradha]

Maybe this is something which an emacs specific nimrod plugin could provide?

[ziotom78]

I didn't think about this solution. Do you think it would be better to modify nimrod-mode than to add a switch to the compiler?

(My idea was that, since the sourcecode:line:column format is recommended by the GNU guidelines, maybe Emacs is not the only program expecting such syntax.)

[Varriount]

This should actually be a pretty easy task. compiler/msgs.nim holds most of the messages, both formatted and unformatted, that are used by the compiler.
All that I think would need to be done is to add the compilation flag, and edit some of the error message procedures.

[reactormonk]

I suppose nimrod idetools should provide the errors, instead of nimrod c.

[zah]

Come on guys, every decent editor has support for modifying the expected error format:
http://praveen.kumar.in/2011/03/09/making-gnu-emacs-detect-custom-error-messages-a-maven-example/

That's what nimrod.vim is doing as well:
https://github.com/zah/nimrod.vim/blob/master/compiler/nimrod.vim

[ziotom78]

Ok, it seems my idea is not interesting enough, so I'll close this issue.

Thanks to everybody for the discussion!

Still would be nice.

[timotheecour]

I refactored all (hopefully) file/line/col formatting used by compiler in a single proc in lib/std/private/miscdollars.nim so this should now be much easier to change (see #8795 for my earlier attempt)

the way I'd like this to work is that passing a compiler option would affect both compiler messages as well as standard runtime messages (assertion backtraces), without having to recompile nim. Many ways to achieve this that are low in complexity.

[lhupfeldt]

Yes, please let us have an option for file:line:col. This is probably the most universal error format.