Re: [Haskell-cafe] how can I get template haskell macro-expanded code from inferStartState? (repeated post, now with subject)

I would say both. The stuff under Examples in the repo should all run with 8.8. (I think currently it doesn't.) The stuff in the wiki should say what is 8.8, what is 8.4, and obviously also give examples that work. The advantage of the wiki is you can make a change that propogates to the community without having commit priviliges for the repo. at least, that's how I've been working. Just changing the wiki for now, and maybe someday when I'm more confident about what I'm doing I'll ask for a commit bit for the repo. thomas. "Brian Brunswick" 08/09/2007 01:28 PM To Thomas Hartman/ext/dbcom@DBAmericas cc haskell-cafe , HAppS@googlegroups.com Subject Re: [Haskell-cafe] how can I get template haskell macro-expanded code from inferStartState? (repeated post, now with subject) On 09/08/07, Thomas Hartman wrote:

(sorry, forgot the subject on my first post)

In the following code which uses template haskell, how can I get back

the

macro-expanded code generated from

$(inferStartState ''MyState)

I just recently used ghc -ddump-splices to debug this very same problem. It turns out to be due to overlapping instances - inferStartState generates a (from memory) specific StartStateEx instance, but actually theres a general StartState => StartStateEx, and also a general Monoid=>StartState instance, and thats why the error message mentions Monoid. I guess this teaches us the reason that overlapping instances are bad: ***They don't work across modules**** Another module can add an instance which wasn't visible when a first module was compiled, and the two modules end up using different instances than expected. I've been meaning to start trying to contribute to improving the HAppS documentation, since its been such a struggle to start learning it. So the question to the HAppS people is, where is the canonical place for this documentation, where should one work? Is it the wiki page above, or the stuff inside the HAppS repository? -- Brian_Brunswick____brian@ithil.org____Wit____Disclaimer____!Shortsig_rules! --- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.