Alternate Clojure syntax (work in progress...and NOT an April Fool's joke)

gistfile1.txt

The majority of parens in Clojure are redundant if we just say that all
n > 1 tokens in a line are arguments to the first token. Parens can be
added in a more C-style to disambiguate within a line. Newline plus
indent expands argument list over multiple lines and each of those
lines gets the original "one-line" treatment. Introducing an "ignore
indent" sigil allows sugaring up the structure. The majority of calls
can be expressed in one line with no parens at all.

Hello world:

defn hello fn([] "Hello world")
hello

Partially expanded:

defn hello
  fn [] "Hello world"
hello

Completely expanded (1ish node per line:

defn
  hello
  fn
    []
    "Hello world"
hello

Immutable data structure example (mostly deleting parens):

let [my-vector [1 2 3 4]
     my-map {:fred "ethel"}
     my-list list(4 3 2 1)]
  list
    conj my-vector 5
    assoc my-map :ricky "lucy"
    conj my-list 5
    ;the originals are intact
    my-vector
    my-map
    my-list

Completely expanded (showing indent and expansion of arrays)

let
  [
    my-vector
      [
        1
        2
        3
        4
    my-map
      {
        :fred
        "ethel"
    my-list
      list
        4
        3
        2
        1
  list
    conj
      my-vector
      5
    assoc
      my-map
      :ricky
      "lucy"
    conj
      my-list
      5
    ;the originals are intact
    my-vector
    my-map
    my-list

Part of a bowling game kata:

0. original code

(defn score-game [rolls]
  (loop [[frame left-rolls] (next-frame (parse-game rolls))
     score 0]
    (cond
     (not (seq frame)) score
     (spare? frame) (recur (next-frame left-rolls)
			   (+ score 10 (first left-rolls)))
     (strike? frame) (recur (next-frame left-rolls)
			    (+ score 10 (first left-rolls) (second left-rolls)))
     :else (recur (next-frame left-rolls)
		  (apply + score frame)))))

1. medium version using indent

defn score-game [rolls]
  loop [[frame left rolls] next-frame(parse-game(rolls)) score 0]
    cond
      not seq(frame)
      score
      spare? frame
      recur next-frame(left-rolls) +(score 10 first(left-rolls))
      strike? frame
      recur next-frame(left-rolls) +(score 10 first(left-rolls) second(left-rolls))
      :else
      recur next-frame(left-rolls) apply(+ score frame)

2. long, fewer parens

defn score-game [rolls]
  loop
    [[frame left rolls] next-frame(parse-game(rolls)) score 0]
    cond
      not seq(frame)
      score
      spare? frame
      recur
        next-frame left-rolls
        + score 10 first(left-rolls)
      strike? frame
      recur
        next-frame left-rolls
        + score 10 first(left-rolls) second(left-rolls)
      :else
      recur
        next-frame left-rolls
        apply + score frame

3. short, more parens

defn score-game [rolls]
  loop [[frame left rolls] next-frame(parse-game(rolls)) score 0]
    cond
      not(seq(frame)) score
      spare?(frame) recur(next-frame(left-rolls) +(score 10 first(left-rolls)))
      strike?(frame) recur(next-frame(left-rolls) +(score 10 first(left-rolls) second(left-rolls)))
      :else recur(next-frame(left-rolls) apply(+ score frame))

4. one long line, most parens

defn score-game [rolls] loop([[frame left rolls] next-frame(parse-game(rolls)) score 0] cond(not(seq(frame)) score spare?(frame) recur(next-frame(left-rolls) +(score 10 first(left-rolls))) strike?(frame) recur(next-frame(left-rolls) +(score 10 first(left-rolls) second(left-rolls))) :else recur(next-frame(left-rolls) apply(+ score frame))))

5. medium, closer to original; => means "ignore indent", pure sugar

defn score-game [rolls]
  loop [[frame left rolls] next-frame(parse-game(rolls)) score 0]
    cond
      not(seq(frame))
        => score
      spare?(frame)
        => recur next-frame(left-rolls) +(score 10 first(left-rolls))
      strike?(frame)
        => recur next-frame(left-rolls) +(score 10 first(left-rolls) second(left-rolls))
      :else
        => recur next-frame(left-rolls) apply(+ score frame)

6. super long, 1ish node per line, minimum parens

defn
  score-game
  [
    rolls
  loop
    [
      [
        frame
          left
          rolls
      next-frame
        parse-game
          rolls
      score
      0
    cond
      not
        seq
          frame
      score
      spare?
        frame
      recur
        next-frame
          left-rolls
        +
          score
          10
            first
              left-rolls
      strike?
        frame
      recur
        next-frame
          left-rolls
        +
          score
          10
        first
          left-rolls
        second
          left-rolls
      :else
      recur
        next-frame
          left-rolls
        apply
          +
            score
            frame

A simple macro. Nothing about this syntax loses homoiconity. It
it simply a different way to delimit sexps.

defmacro on-debug [& body]
  `when DEBUG
     do ~@body

@technomancy Consider it a thought exercise. All I'm doing here is delimiting sexps a different way; they're still there, line by line.

@tomjack score is defined in the loop preamble. It got lost in my initial translation, but I've fixed that now. You may have found an ambiguity, though, between a simple value and applying a zero-arg function; latter might need () to apply.