forked from GitHub/gf-core
By adding the flag -haskell=variants to the command line, GF will now generate
linearization functions in Haskell that support variants. Variants are
represented as lists in Haskell.
Variants inside pre { ... } expressions are still ignored.
TODO: apply some monad laws to generate more compact code (using an
intermediate representation of the generated Haskell code, instead of
pretty printing directly from the GF code).