Hi, Am Dienstag, den 16.01.2018, 11:08 -0500 schrieb Joachim Breitner: > in a GHC plugin, I want to synthesize simple data structures, and > insert them into the code. What is the most idiomatic way of writing a > function, say, > > foo :: Maybe String -> CoreExpr > > or > > foo :: Maybe String -> CoreM CoreExpr > > so that the resulting CoreExpr describes the input. Abstractly > speaking, I could imagine creating the Core AST by hand (but I’d have > to figure out how to resolve the names of the constructors), or somehow > invoking the renamer, type-checker and desugarer from within CoreM.
I ended up writing this:
dcExpr :: TH.Name -> CoreM CoreExpr
dcExpr thn = do
Just name <- thNameToGhcName thn
dc <- lookupDataCon name
pure $ Var (dataConWrapId dc)
resultToExpr :: Result -> CoreM CoreExpr
resultToExpr (Success s) = App <$> dcExpr 'Success <*> mkStringExpr s
resultToExpr (Failure s) = App <$> dcExpr 'Failure <*> mkStringExpr s
which seems to work fine.
Cheers,
Joachim
--
Joachim Breitner
m...@joachim-breitner.de
http://www.joachim-breitner.de/
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