Returned by Bf.parse/1 and raised by Bf.parse!/1 when a program's
brackets don't match.
reason is :unmatched_open for a [ without a matching ], and
:unmatched_close for a ] without a matching [. line and column
point at that bracket. Both start at 1, and columns count graphemes.
Summary
Types
@type t() :: %Bf.ParseError{ __exception__: term(), column: pos_integer(), line: pos_integer(), reason: :unmatched_open | :unmatched_close }