Indenter for Janet

spork/fmt is a compact elegant formatter for Janet by bakpakin.

It works by parsing source while discarding whitespace (except newlines) and then emits newly formatted source possibly removing some newlines and inserting whitespace in appropriate locations.

It's fast, but it might discard some whitespace-related information that one might prefer preserved.

jandent is based on spork/fmt but it attempts to preserve whitespace information to the right of indentation, e.g.

     (+ 1 1)   # a comment
^^^^^       ^^^
| |          |
| |          --- whitespace is preserved
| |              (right of indentation)
| |
|  --- indentation
|
 --- beginning of line

See the Details section below for further examples.

The API is the same as spork/fmt:

• format-print
• format
• format-file

There is also a standalone executable named jindt, which is essentially jfmt for jandent.

• Leave whitespace to the right of indentation alone
• Handle "data" tuples
• Prevents closing delimiters from living in the left-most column
• Doesn't remove newlines
• Doesn't add newline at end
• Treat comment as an "indent with 2 spaces" item

spork/fmt's approach is quick but it can adversely impact some situations involving contiguous whitespace.

If you have columnar alignment like:

(let [ant   1
      tiger 2]
  (+ ant tiger))

At the time of this writing, spork/fmt will turn this into:

(let [ant 1
      tiger 2]
  (+ ant tiger))

Another situation has to do with whitespace before comments, like:

{:a 1   # this nice comment
 :b 20  # another comment
 :c 3}

Similarly, this will become:

{:a 1 # this nice comment
 :b 20 # another comment
 :c 3}

jandent should leave such whitespace intact.

The following changes were made to aid comprehension and exploration:

• Use longer names in pegs
• Some code reformatting
• No top-level private defs or defns
• Has a bit more commentary

• andrewchambers - jfmt
• bakpakin - spork/fmt
• llmII - discussion

Code from spork/fmt was modified and included, thus spork's license applies.