Development/DarcsLibraries

This is the perfect project for a non-darcs Haskeller to get on. Good for us, good for the whole Haskell community. Approach : identify likely haskellers (e.g. authors/maintainers of respective hackage packages) and ask for their help?

We should spin off

Things that probably should be spun off into standard libraries (or merged with, replaced with, etc)

  • Diff detection, edit distance, lcs, code

    • Gwern has imported Lcs.lhs into the lcs package maintained by Igloo; he was just waiting on relicensing permission from Dr. Roundy
  • Crypto stuff (issue2043)

    • the folks behind the Crypto package seem to say that our implementation of SHA1 (was it sha1?) was faster but more imperative… so what to do here? Can we make the functional crypto faster? Should we submit our code as a fast crypto variant of the pure implementation?
    • there is also the SHA package (which says it’s slow)
  • Date parsing

  • System.Posix stuff for windows (package: unix-compat ?)

    • Unfortunately, the unix-compat package does not currently export everything we need (ie. no System.Posix, no System.Posix.IO) and it’s unclear to me why the CtrlC.hs module.
  • Fetching remote files (curl on Hackage, but maybe generic wrapper for curl/libwww/HTTP)
  • XML handling can probably be reduced; no doubt a lot of the functions in src/Darcs/Patch/Viewing.lhs are redundant with xml or something^[But then, which XML library? There’s more than one. Probably not HaXml as too big a dep.].
  • Advanced printing: Darcs.ColorPrinter and Printer

  • Progress reporting framework

    • Need permission from David to BSD-license this
  • Commands/subcommands/arguments infrastructure

  • Typed filepaths

  • MIME parsing/generation

We have spun off

  • Gzip/gunzip (interactions with bytestring)

  • bytestring

    • done by DonStewart during darcs hacking sprint #1 (2008-10)
  • mmap

  • filepath stuff - we have our idiosyncrasies

    • From issue341: “I’m not convinced that System.FilePath is a route we’d want to go. We already have code that is almost certainly better tested than System. FilePath and that we understand.” –DavidRoundy 2006-11
    • Potential pitfalls

      • encode/decode white
      • utf-8 (should not affect filepath; just packing)
      • safeFileChar?
      • 100% backwards-compatibility for internal patch stuff (safest bet is not to change code)

      • subtle semantic differences
    • Good news: it’s just the FilePath type we’re dealing with here (i.e. String), so it should be a relatively painless switch.
    • EricKow has done some work to replace some of our ad-hoc code with filepath code; there may be more to go, though

  • slurpies (file trees)