jacinda-0.3.1.0: lib/sed.jac
@include'prelude/fn.jac'
{. example: (replace /^var/ 'export const')"$0
fn replace1(re, str, line) :=
let
val insert := \line. \str. \ixes.
take (ixes->1) line + str + drop (ixes->2) line
in option line (insert line str) (match line re) end;