ceta should export nat_of_integer

[jwaldmann]

my main program does import Ceta to call

certify_proof ::
  Bool ->
    Maybe [Char] ->
      Sum (Claim (Lab [Char] [Nat]) [Char]) [Char] -> [Char] -> Cert_result;

We have

data Claim a b = Yes | No | Terminating | Upperbound Nat | Nonterminating
  | Confluent | Nonconfluent | Completed | Ordered_Completed | Anything;

but

module
  Ceta(Nat,

so I cannot construct Upperbound Nat.

(see #19 )

[jwaldmann]

I can fix this manually for now (just add the export) but it's not stable.

[jwaldmann]

the commit is the work-around, I keep the issue open.

[csternagel]

With changeset f1285556fa56 of IsaFor ( http://cl2-informatik.uibk.ac.at/rewriting/mercurial.cgi/IsaFoR ) nat_of_integer is now exported by Ceta.hs.