Does clojure community have an equivalent of perltidy?

Question

I have a function definition like so:

(defn init-globals [] (def *board-width* 15))

I want to be able to reformat so that it looks something like:

(defn init-globals []
   (def *board-width* 15))

I would like the formatting to be done by an intelligent agent that doesn't merely indent everything a fixed amount, or just prints one element per line etc. This is something that perltidy does.

perltidy takes code like:

sub foo {
my $args = shift;    $a = $args->{a}; $long_var = $args->{b}; }

and turns it into:

sub foo {
    my $args = shift;
    $a        = $args->{a};
    $long_var = $args->{b};
}

Notice how it considers the "sub" defintion as a whole, and even the "=" on the last two assignments line up. While I don't necessarily need this level of formatting, I would like something that takes a list (or more accurately, a form), that is a function with args and subexpressions, and makes it as human readable as possible.

The reason my function definition is a single line is because it's generated from a macro. I don't want to clutter up the macro with formatting instructions (if indeed I can even do this without generating a string instead of a list) because macros are hard enough as it is. While I can eval the list into my REPL just fine, I would also like to write the generated code to a file as if it were typed in by hand i.e something you could check into source control.

I've looked at things like (clojure.pprint/pp), and using emacs 'indent-sexp and smartparen's 'sp-indent-defun, but they don't split the output into multiple lines among other things.

I can interop with emacs/elisp commands, so if there's a way to do it with emacs, that would work too.

@noisesmith I think the outer def here is supposed to be a macro emitting the list (def ...) and the backquote got lost in translation. — arrdem
just use any proper clojure code editor from the following list: [:emacs] and it'll do it for you ;) — iced

arrdem arrdem · Accepted Answer · 2015-03-12T05:24:13

If this is what you want to do, then I'd suggest simply printing your generated code (or however you want to write it to a file) and then throwing cljfmt at it.

There exist tools such as bbloom's Fipp which can do similar code pretty-printing from inside a Clojure instance, but to the best of my knowledge cljfmt does a better job.

I think that it's worth considering why you are attempting to save macroexpanded code, since the cost of macroexpansion is nominal and it would be considered better practice to generate code as-needed rather than to generate code, save it, and then handle it as if it had been hand-written. Retaining code generation also means that your codebase is more flexible in that you can just tweak the generator and reload the namespaces involved rather than having to regenerate the generated code, and then reformatting and recompile that.

Does clojure community have an equivalent of perltidy?

2 Answers