From 1e2b20dfefd0aad425853137d2b4d2cb899bd6d7 Mon Sep 17 00:00:00 2001
From: fanghr <chfanghr@gmail.com>
Date: Fri, 29 Apr 2022 17:22:44 +0800
Subject: [PATCH] reimplement `mustFindDatum'` with `PTryFrom`

---
 agora/Agora/Governor.hs | 10 ++++------
 agora/Agora/Utils.hs    | 14 ++++++--------
 2 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/agora/Agora/Governor.hs b/agora/Agora/Governor.hs
index 10e4131..8839868 100644
--- a/agora/Agora/Governor.hs
+++ b/agora/Agora/Governor.hs
@@ -119,7 +119,7 @@ import Plutarch.Map.Extra (pkeys, plookup, plookup')
 import Plutarch.Monadic qualified as P
 import Plutarch.SafeMoney (PDiscrete, Tagged (..), puntag, pvalueDiscrete)
 import Plutarch.Unsafe (punsafeCoerce)
-import Plutarch.TryFrom(PTryFrom(..))
+import Plutarch.TryFrom(PTryFrom(..), ptryFrom)
 
 --------------------------------------------------------------------------------
 
@@ -356,8 +356,7 @@ In this case, the script will check
 governorValidator :: Governor -> ClosedTerm PValidator
 governorValidator gov =
   plam $ \datum' redeemer' ctx' -> P.do
-    -- TODO: use ptryFrom
-    redeemer <- pmatch $ pfromData @PGovernorRedeemer $ punsafeCoerce redeemer'
+    (pfromData -> redeemer, _) <- ptryFrom redeemer'
     ctx <- pletFields @'["txInfo", "purpose"] ctx'
 
     txInfo' <- plet $ pfromData $ ctx.txInfo
@@ -374,8 +373,7 @@ governorValidator gov =
     ownInput <- pletFields @'["address", "value"] ownInput'
     let selfAddress = pfromData $ ownInput.address
 
-    -- TODO: use ptryFrom
-    let oldParams' = pfromData @PGovernorDatum $ punsafeCoerce datum'
+    (pfromData -> (oldParams' :: Term _ PGovernorDatum), _) <- ptryFrom datum'
     oldParams <- pletFields @'["proposalThresholds", "nextProposalId"] oldParams'
 
     let ownInputGSTAmount = stateTokenValueOf # ownInput.value
@@ -402,7 +400,7 @@ governorValidator gov =
             mustBePJust # "Ouput governor state datum not found"
               #$ pfindDatum # outputGovernorStateDatumHash # txInfo'
 
-    case redeemer of
+    pmatch redeemer $ \case 
       PCreateProposal _ -> P.do
         let expectedNextProposalId = pgetNextProposalId # oldParams.nextProposalId
             expectedNewDatum =
diff --git a/agora/Agora/Utils.hs b/agora/Agora/Utils.hs
index 2ad5d86..a1b88b3 100644
--- a/agora/Agora/Utils.hs
+++ b/agora/Agora/Utils.hs
@@ -529,13 +529,10 @@ hasOnlyOneTokenOfCurrencySymbol = phoistAcyclic $
     psymbolValueOf # cs # vs #== 1
       #&& (plength #$ pto $ pto $ pto vs) #== 1
 
-{- Find datum given a maybe datum hash, in an unsafe manner.
-
-   FIXME: reimplement using 'ptryFrom'.
--}
+-- | Find datum given a maybe datum hash
 mustFindDatum' ::
   forall (datum :: PType).
-  PIsData datum =>
+  (PIsData datum, PTryFrom PData (PAsData datum))=>
   forall s.
   Term
     s
@@ -545,9 +542,10 @@ mustFindDatum' ::
     )
 mustFindDatum' = phoistAcyclic $
   plam $ \mdh datums -> P.do
-    PDJust ((pfield @"_0" #) -> dh) <- pmatch mdh
-    PJust dt <- pmatch $ plookupTuple # dh # datums
-    punsafeCoerce dt
+    let dh = mustBePDJust # "Given TxOut dones't have a datum" # mdh
+        dt = mustBePJust # "Datum not found in the transaction" #$ plookupTuple # dh # datums
+    (d, _ ) <- ptryFrom $ pforgetData $ pdata dt
+    pfromData d
 
 {- | Extract the value stored in a PMaybe container.
      If there's no value, throw an error with the given message.