lithp | Tim Menzies

http://tiny.cc/lithp

lithp is less library: the smallest set of Common Lisp add-ons that measurably shrinks application code — five plain constructs plus a handful of utilities, ~130 lines total, no reader macros, no dependencies. Found by ablation: we wrote the same machine-learner four ways and kept only what paid rent. The why, the data, and the style rules are in blog.md — this file is just the manual.

git clone http://tiny.cc/optimiz # access test data
git clone http://tiny.cc/lithp && cd lithp
sbcl --script fft.lisp          # the sweet-spot version
sbcl --script fft.lisp --trees  # show all grown trees
sbcl --script fft.lisp --grows  # timing benchmark

NAME

lithp — less library: the pay-rent subset (130 lines, no deps)

SYNOPSIS

(load "lithp.lisp")
(defvar *settings* '((seed . 1234567891) (file . "data.csv")))
(defmacro my (k) `(cdr (assoc ',k *settings*)))
(cli *settings*)                ; -s 42 on argv updates seed
(setf *seed* (my seed))

THE KIT (five constructs)

form	meaning
`(fn expr)`	variadic lambda; refer to args as `$1`..`$9` as used
`(? x a b)`	quoted-key chained access: `(ats (ats x 'a) 'b)`
`(let+ (...) ...)`	one binder: `(x 1)` let, `((a b) lst)` destructure, `(f (z) ...)` local fn
`(o 'k1 v1 'k2 v2)`	build equal-hash record
`(ats x k)`	read hash or struct slot uniformly; setf-able

Plus (keys h) — list of hash keys.

UTILITIES

group	functions
print	`(cat ...)` strings together; `(prn fmt args...)` format + newline
pick	`(least lst f)` / `(most lst f)` — min/max by key fn
parse	`(thing s)` string→number/symbol; `(cells s)` split csv line; `(csv file)` rows of things
cli	`(args)` argv; `(cli alist)` `-x val` sets first-char-matching key
random	`(rand n)` `(rint n)` `(shuffle lst)` `(few lst n)` — seeded Park-Miller (`seed`), reproducible across languages

FILES

file	what
`lithp.lisp`	this library
`blog.md`	the ablation study: why these and only these
`yuck.lisp`	naive CLOS port, 605 lines — the cautionary tale
`small.lisp`	plain ANSI CL, design only, 261 lines
`fft.lisp`	+ the kit, 240 lines — the sweet spot
`to_small.lisp`	+ reader macros via `tiny.lisp`, 214 lines — fun, not leverage
`tiny.lisp` / `tiny.vim`	the full dialect and its required editor support

All four programs (fft, small, to_small, yuck) produce byte-identical output (same seeded RNG as the Python original they port).

LICENSE