[Template-haskell] How to get list of instances of a given class?

Dimitry Golubovsky golubovsky at gmail.com
Tue Dec 13 09:37:49 EST 2005

Bulat kindly pointed me to the SerTH example. I also have been trying
to browse the GHC documentation trying to find the answer to my

I see, for example, what can be gotten for a class (provided that the
name of the class is known):

data Dec
ClassD Cxt String [String] [Dec]  -- or ClassD Cxt Name [Name]
[FunDep] [Dec] in
InstanceD Cxt Type [Dec]

The documentation (neither for 6.2.2 nor for the latest) says nothing
about what is in [Dec] for a class. Are instances of the class known
at the moment of slplicing contained there?

I may be asking too common questions. I just need to see whether my
task is accomplishable via TH. If it is not, then I'll do this via
some plugins to HSFFIG, but the latter is not much desirable.

Please advise.


Dimitry Golubovsky

Anywhere on the Web

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