Languages

The same script in each language Weft speaks. All four compile to the same ops (the counter below is 91 bytes in each) and share one standard library.

JavaScript91 bytes

let n = load("count") ?? 0
store("count", n + 1)
log("run", n + 1)

Open in the playground

Python91 bytes

n = load("count") or 0
store("count", n + 1)
print("run", n + 1)

Open in the playground

Lua91 bytes

local n = load("count") or 0
store("count", n + 1)
print("run", n + 1)

Open in the playground

Lisp91 bytes

(define n (or (load "count") 0))
(store "count" (+ n 1))
(log "run" (+ n 1))

Open in the playground

Language	Blocks and loops	Values
JavaScript	let/const, function, arrows, if, while, for, for…of, for…in	numbers, strings, arrays, objects, template strings, ?? and ?:
Python	def, lambda, if/elif/else, while, for over range, lists, dicts, items(), enumerate()	lists, dicts, f-strings, slices, in
Lua	local, function, if/elseif, while, repeat, numeric for, pairs, ipairs	tables as 1-based lists and maps, .., #, s:method()
Lisp	define, lambda, if, cond, let, begin, while, for, dotimes	lists, dicts, strings; the last form is the value

Truthiness is one rule in every language: nil, false, 0 and the empty string are false; everything else is true.