Juvix Emacs mode tutorial

First, follow the instructions in the Emacs Mode Reference to install the Juvix Emacs mode. Once you've successfully set it up, create a file Hello.juvix with the following content.

module Hello;

open import Stdlib.Prelude;

main : IO;
main := printStringLn "Hello world!";

end;

Type C-c C-l to run the scoper and highlight the syntax.

If you make a mistake in your program, it is automatically underlined in red with the error message popping up when you hover the mouse pointer over the underlined part.

For example, in the following program the identifier printStringLna should be underlined with the error message "Symbol not in scope".

module Hello;

open import Stdlib.Prelude;

main : IO;
main := printStringLna "Hello world!";

end;

If error underlining doesn't work, make sure you have the flycheck mode turned on. It should be turned on automatically when loading juvix-mode, but in case this doesn't work you can enable it with M-x flycheck-mode.

Let's extend our program with another definition.

module Hello;

open import Stdlib.Prelude;

print : IO;
print := printStringLn "Hello world!";

main : IO;
main := print;

end;

Place the cursor on the print call in the function clause of main and press M-.. The cursor will jump to the definition of print above. This also works across files and for definitions from the standard library. You can try using M-. to jump to the definition of printStringLn.

One more feature of the Juvix Emacs mode is code formatting. To format the content of the current buffer, type C-c C-f. Here is the result.

module Hello;
  open import Stdlib.Prelude;

  print : IO;
  print := printStringLn "Hello world!";

  main : IO;
  main := print;
end;