On Tue, Nov 8, 2011 at 11:28 PM,
I don't agree that GHC's user interface should be optimized for newcomers to Haskell. GHC is an industrial-strength compiler with some very advanced features; the majority of its target audience is professional programmers. Let its interface reflect that fact.
As Simon explained, GHC's current defaults are a very nice point in the programming space for people who are actively building and changing their programs.
It's easy to build arguments for either side, but my experience as a professional developer is that new devs don't know what arguments they need for reasonable performance, often knowing even what various optimization flags do, but experienced developers do know the difference between -O0 and -O1, and frequently need -debug (not a default option) more than -O0. Seasoned GHC users can find that -O0 gives miserably slow compile times, and fall back to GHCi for edit/rebuild cycles... which still aren't terribly fast if you're using GHC's advanced features. I have a couple small modules that take 10 minutes each to compile on a current Core i7 at -O0, and -O2 really doesn't take much longer. GHCi is very slightly faster but I'll still head directly downstairs for a coffee as soon as either of these bad boys need rebuilding... and still make it back upstairs before they're done. And so I'd prefer the default to be -O1 or even -O2 and have people who really need it use -O0. GHC shouldn't be painful on purpose, industrial strength or not. -n