jacinda-0.3.1.0: examples/sed.jac
{. program equiv to s/^(type|interface)/export \1/
@include'prelude/fn.jac'
fn replaceAtWith(line, ixes) :=
let
val pre := take (ixes->1) line
val at := drop (ixes->1) line {. in our case
in pre + 'export ' + at end;
fn replaceAt(line) :=
option line (replaceAtWith line) (match line /^(type|interface)/);
replaceAt"$0