Have you tried Multiplate?
If Multiplate is not powerful enough and you're willing to make your types
more complex, have a look at deep-transformations.
On Mon, May 24, 2021 at 4:52 PM Richard Yu
I have a question about generic traversal/transformation of nested data structures. From what I understand the main options available are SYB, Uniplate, GHC.Generics and Data.Lens (although I am under the impression this requires record types). The data structure I am attempting to traverse is similar to this simplified version:
data SExpr = Expr | Const data Const = B bool | I int data Expr = Lambda String SExpr | If Expr ...
I have attempted to use Uniplate and GHC.Generics to traverse the built AST and modify for example, the string of a Lambda type, but have not been able to figure out how to get any of the libraries to typecheck. The examples or docs I found were not quite enough. Does anyone know of examples that might help or explain how I should be using the generic libraries? In addition if I moved to writing the AST with GADTs, do some generic traversal strategies/libraries stop working?
Many thanks, Richard
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