:post run = "check" :l = [1] :n = 0 $ f(t) ~ t!insert(len(l)+1) f1: {l} {t} CHECK ยง c ~ n < 1 REC ~ n += 1 ~ f(t) END REC ~ t!insert(len(t)+1) ~ error("t") f2: {l} ~ f(l) FINAL l: {l} $ check AFTER ERROR l: {l}