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diff --git a/doc/design/assistant/blog/day_236__evil_splicer.mdwn b/doc/design/assistant/blog/day_236__evil_splicer.mdwn new file mode 100644 index 000000000..72c8f51a9 --- /dev/null +++ b/doc/design/assistant/blog/day_236__evil_splicer.mdwn @@ -0,0 +1,29 @@ +Spent today bulding the Evil Splicer, a program that parses `ghc -ddump-splices` +output, and uses it to expand Template Haskell splices in source code. +I hope to use this crazy hack to get the webapp working on Android. + +This was a good opportunity to use the +[Parsec](http://hackage.haskell.org/package/parsec) library for parsing the +ghc output. I've never really used it before, but found it quite nice to +work with. The learning curve, if you already know monads and applicatives, +is about 5 minutes. And instead of ugly regular expressions, you can work +with nice code that's easily composable and refactorable. Even the ugly +bits come out well: + +[[!format haskell """ + {- All lines of the splice result will start with the same + - indent, which is stripped. Any other indentation is preserved. -} + i <- lookAhead indent + result <- unlines <$> many1 (string i >> restOfLine) +"""]] + +Anyway, it works.. sorta. The parser works great! The splices that ghc +outputs are put into the right places in the source files, and formatted in +a way that ghc is able to build. Often though, they contain code that +doesn't actually build as-is. I'm working to fix up the code to get closer +to buildable. + +---- + +Meanwhile, guilhem has made ssh connection caching work for rsync special +remotes! It's very nice to have another developer working on git-annex. :) |