But I can't find such a ByteArray type definition in today's common packages. What's the rationale for this piece of code?
Doing some archeology they seem to have been removed from ghc/lib/std/PrelArr.lhs in e921b2e307532e0f30eefa88b11a124be592bde4 (1999): data Ix ix => Array ix elt = Array ix ix (Array# elt) -data Ix ix => ByteArray ix = ByteArray ix ix ByteArray# data Ix ix => MutableArray s ix elt = MutableArray ix ix (MutableArray# s elt) -data Ix ix => MutableByteArray s ix = MutableByteArray ix ix (MutableByteArray# s) So it's probably dead code since then. Cheers, Sylvain On 10/10/2019 21:15, Shao, Cheng wrote:
Hello devs,
I've been trying to figure out how to pass lifted types as foreign types, then encountered the following code in the `DsCCall` module (https://gitlab.haskell.org/ghc/ghc/blob/master/compiler/deSugar/DsCCall.hs#L...):
``` -- Byte-arrays, both mutable and otherwise; hack warning -- We're looking for values of type ByteArray, MutableByteArray -- data ByteArray ix = ByteArray ix ix ByteArray# -- data MutableByteArray s ix = MutableByteArray ix ix (MutableByteArray# s) | is_product_type && data_con_arity == 3 && isJust maybe_arg3_tycon && (arg3_tycon == byteArrayPrimTyCon || arg3_tycon == mutableByteArrayPrimTyCon) = do case_bndr <- newSysLocalDs arg_ty vars@[_l_var, _r_var, arr_cts_var] <- newSysLocalsDs data_con_arg_tys return (Var arr_cts_var, \ body -> Case arg case_bndr (exprType body) [(DataAlt data_con,vars,body)] ) ```
It seems we allow a "ByteArray" type as a foreign import argument, if the third field of the datacon is a ByteArray# or MutableByteArray#. But I can't find such a ByteArray type definition in today's common packages. What's the rationale for this piece of code?
Cheers, Cheng _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs