quox/lib/Quox/CheckBuiltin.idr

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||| check that special functions (e.g. `main`) have the expected type
module Quox.CheckBuiltin
import Quox.Syntax
import Quox.Typing
import Quox.Whnf
%default total
export covering
expectSingleEnum : Definitions -> TyContext d n -> SQty -> Loc ->
Term d n -> Eff Whnf ()
expectSingleEnum defs ctx sg loc s = do
let err = delay $ ExpectedSingleEnum loc ctx.names s
cases <- wrapErr (const err) $ expectEnum defs ctx sg loc s
unless (length (SortedSet.toList cases) == 1) $ throw err
||| `main` should have a type `1.IOState → {𝑎} × IOState`,
||| for some (single) tag `𝑎`
export covering
expectMainType : Definitions -> Term 0 0 -> Eff Whnf ()
expectMainType defs ty =
wrapErr (WrongBuiltinType Main) $ do
let ctx = TyContext.empty
(qty, arg, res) <- expectPi defs ctx SZero ty.loc ty
expectEqualQ ty.loc qty One
expectIOState defs ctx SZero arg.loc arg
let ctx = extendTy qty res.name arg ctx
(ret, st) <- expectSig defs ctx SZero res.loc res.term
expectSingleEnum defs ctx SZero ret.loc ret
let ctx = extendTy qty st.name ret ctx
expectIOState defs ctx SZero st.loc st.term