After 1.0:
- bugbear?
- match-span -s ... -s ..s (update: does this mean multiple starts?)
- print last section without --failure if read-cmd exits with non-zero (how?)
- option to turn off stderr dots for hidden sections
- read-cmd time (and maybe for each section?)
- collapse any repeated lines
- make dedupe_blank_lines optional
- short command aliases (four-letter ones)
- match/head/tail --repl spans of skipped lines with ... (match span already does this)
- a way to reuse pre-configured commands
- split --only-delimited
- split --output-format '{1}{2!r}'? requires a custom string.Formatter that coerces string arguments
- parse -D/--output-delimiter (account for both : and ,)
- parse --all/--findall to match multiple times? (like match -o); we need re.findall() for multiple patterns, though
- parse --prefix-non-matching UNKNOWN ->
["UNKNOWN", line]/{"UNKNOWN": line}