Hi again, I'm still trying to figure out my earlier problem regarding the directory tree and functions on the files. What I'm really trying to do sounds simple enough: find duplicate files for a complete directory, given a root. The original approach I had in mind was to compute every file's checksum, which I could feed into a map of (checksums,[filepaths]). On 03/10/2012 01:48 PM, Chaddaï Fouché wrote:
Note that you solution isn't very "functional-like", but rather imperative. On the other hand, making it more functional in this particular case come with its own brand of subtle difficulties.
I now wonder how to achieve my goal properly in Haskell. Obviously I have some sequential parts of my program (reading directory trees is I/O and therefore monadic), but it seems to me that could also be some functional part as well (pairing files with checksums, pairing checksums with common filepaths, filtering only checksums with more than one filepath, maybe even sorting, etc.). How would you go about to do it? Which parts of the program should be monadic, which functional? Would you create a custom-build monad or would you use build-ins (which ones?)? I would really like to have some pointers how an experienced Haskell developer would go about such a thing, since I want to acquire a Haskell feel of programming rather than keep on programming in my old ways, now in Haskell. I would also be happy to be simply pinpointed to other applications which source code are exemplary, but not too huge to dig through in a sensible amount of time. (I'm currently trying to work through the Darcs source code, but that seems a bit too overkill.) Thanks for any comments and thoughts. Best, Michael