Canonical formatter: width-aware meme output.
Composes printer (form → Doc) with render (layout @ target width).
Used by `meme format` CLI command.

Flat formatter: single-line meme output.
Composes printer (form → Doc) with render (layout @ infinite width).

Meme printer: Clojure forms → Doc trees.
Builds Wadler-Lindig Doc trees from Clojure forms, handling meme syntax
(call notation, sugar, metadata, comments) and Clojure output mode.
Delegates to render for Doc algebra and layout.

Wadler-Lindig document algebra and layout engine.
Generic — no meme-specific knowledge. Reusable for any pretty-printing task.

Doc types form a small algebra:
  DocText     — literal string
  DocLine     — newline+indent (or flat-alt when flat)
  DocCat      — concatenation
  DocNest     — increase indent
  DocGroup    — try flat, break if too wide
  DocIfBreak  — conditional on flat/break mode

layout renders a Doc tree to a string at a given page width.
Use ##Inf for single-line (flat) rendering.