A library for detecting file changes.
Delta is a library for detecting file changes in any given directory. The package is written using the sodium FRP library but it also provides a callback based API.
File changes on OS X are based on the FSEvents API that is also used by TimeMachine. On other operating systems the library currently uses recursive descents in directories. I will include inotify for Linux. If someone would like to have a non-polling based API for windows or BSD, I would really like it if anyone would contribute.
The project also contains an executable, delta-run, which allows you to run arbitrary shell commands when a file in a directory (recursively) changes.
$> delta-run --help
Usage: delta-run [-i|--interval INTERVAL] [-v|--verbose] FILE CMD
Available options:
-h,--help Show this help text
-i,--interval INTERVAL Run at most every n seconds
-v,--verbose Print extra output
FILE The directory that is watched
CMD The command to run
For example you could use delta-run to rebuild your project everytime the source changes like this: delta-run ./src "cabal build"