Hi,
Suppose I have the following types:
> data Expr expr = Lit Nat | Add (expr, expr)
> newtype Fix f = Fix {unFix :: f (Fix f)}
I can construct a sample term:
> term :: Expr (Expr (Expr expr))
> term = Add (Lit 1, Add (Lit 2, Lit 3))
But isn't quite what I need. What I really need is:
> term' :: Fix Expr
> term' = Fix . Add $ (Fix . Lit $ 1, Fix . Add $ (Fix . Lit $ 2, Fix . Lit
$ 3))
I feel like there's a stupidly simple way to automatically produce term'
from term, but I'm not seeing it.
Any ideas?
Best,
Sebastien
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