On Fri, Feb 5, 2010 at 8:55 PM, Edward Kmett
You can add me to the list of voices that were unwilling to use it before the summer-of-code project due to the random incompatibilities caused by the huge supply of extensions it supported out of the box, but who were happy to switch to it after the changes were made to make them configurable.
This was indeed the main priority of the project, and the reason why even I would not have recommended anyone to use haskell-src-exts in production before the project.
The rest is just gravy that happens to permit a number of applications such as refactoring browsers that were impossible with the previous implementation. And, as I recall, the fairly radical exploratory "pretty print . parse = id" goal was explicitly listed merely as a secondary goal on the original application.
Indeed it was, and I am not aware of any major applications that actually use the exact-print functionality yet (please, tell me if you have one!). I do know of several that make very good use of the new Annotated syntax tree, though, which was introduced as a step towards exact-printing. The benefits of that, together with the configurable extensions, is more than enough to now make me happily recommend haskell-src-exts to anyone working with Haskell source code in any application. The rest is, as you accurately put it, just gravy. I must admit I'm a bit sad to have the value of my project questioned in this way, a project that I myself was more than pleased with, both with the actual work achieved and the significant positive feedback I have received after its conclusion. If haskell-src-exts was indeed popular even before the project, that's all well and good to me. But it doesn't mean that the library offered to the users then was satisfactory, nor does it mean that the project failed to deliver something that those same users needed and/or could make good use of. Even if the number of direct users did not rise dramatically as a consequence of the project, why would it not be valid use of a project slot to greatly improve a library that was already popular? Browsing the numbers [1] posted by Don Stewart in September last year (the Haskell Symposium figures, which is the latest I could find) suggests a substantial increase of downloads of the package both before, during and after the project, but I can only speculate why. And since the project concluded late August, figures for September and onwards would have been more telling. I'm at a loss as to what criteria is actually used to judge success here. It seems to me a bit like the eternal discussion between "basic research" and "applied research". Just because something (research/library/project) doesn't have an immediate, palpable impact and/or delivers a visible tool, that certainly doesn't imply that it doesn't have merit or won't have as profound an impact on the domain, if more diffuse than a tool (or other palpable deliverable) would. /Niklas [1] http://www.galois.com/~dons/hackage/september-2009/total-downloads.html