apply @chfanghr's suggestions

agora/Agora/AuthorityToken.hs

@@ -32,7 +32,9 @@ import Plutarch.Api.V2 (
 import Plutarch.Extra.AssetClass (passetClass, passetClassValueOf)
 import Plutarch.Extra.List (plookup)
 import Plutarch.Extra.ScriptContext (pisTokenSpent)
-import Plutarch.Extra.TermCont (pguardC, pletFieldsC, pmatchC)
+import Plutarch.Extra.Sum (PSum (PSum))
+import Plutarch.Extra.TermCont (pguardC, pletC, pletFieldsC, pmatchC)
+import Plutarch.Extra.Traversable (pfoldMap)
 import Plutarch.Extra.Value (psymbolValueOf)
 import PlutusLedgerApi.V1.Value (AssetClass (AssetClass))
 
@@ -111,19 +113,32 @@ singleAuthorityTokenBurned gatCs inputs mint = unTermCont $ do
   let gatAmountMinted :: Term _ PInteger
       gatAmountMinted = psymbolValueOf # gatCs # mint
 
+  let inputsWithGAT =
+        pfoldMap
+          # plam
+            ( flip pmatch $ \case
+                PTxInInfo txInInfo -> unTermCont $ do
+                  resolved <- pletC $ pfield @"resolved" # txInInfo
+
+                  pguardC "While counting GATs at inputs: all GATs must be valid" $
+                    authorityTokensValidIn # gatCs
+                      #$ pfromData
+                      $ resolved
+
+                  pure . pcon . PSum $
+                    psymbolValueOf
+                      # gatCs
+                      #$ pfield @"value"
+                      #$ resolved
+            )
+          # inputs
   pure $
     foldr1
       (#&&)
-      [ ptraceIfFalse "singleAuthorityTokenBurned: Must burn exactly 1 GAT" $ gatAmountMinted #== -1
-      , ptraceIfFalse "singleAuthorityTokenBurned: All GAT tokens must be valid at the inputs" $
-          pall
-            # plam
-              ( \txInInfo' -> unTermCont $ do
-                  PTxInInfo txInInfo <- pmatchC txInInfo'
-                  let txOut' = pfield @"resolved" # txInInfo
-                  pure $ authorityTokensValidIn # gatCs # pfromData txOut'
-              )
-            # inputs
+      [ ptraceIfFalse "singleAuthorityTokenBurned: Must burn exactly 1 GAT" $
+          gatAmountMinted #== -1
+      , ptraceIfFalse "Only one GAT must exist at the inputs" $
+          inputsWithGAT #== 1
       ]
 
 {- | Policy given 'AuthorityToken' params.

agora/Agora/Effect.hs

@@ -10,13 +10,9 @@ module Agora.Effect (makeEffect) where
 import Agora.AuthorityToken (singleAuthorityTokenBurned)
 import Plutarch.Api.V1 (
   PCurrencySymbol,
-  PMap (PMap),
-  PValue (PValue),
  )
-import Plutarch.Api.V1.AssocMap (plookup)
 import Plutarch.Api.V2 (
   PScriptPurpose (PSpending),
-  PTxInInfo (PTxInInfo),
   PTxInfo,
   PTxOutRef,
   PValidator,
@@ -70,28 +66,6 @@ makeEffect gatCs' f =
     txInfo <- pletFieldsC @'["mint", "inputs"] ctx.txInfo
     gatCs <- pletC $ pconstant gatCs'
 
-    -- FIXME(emiflake): This is somewhat inefficient, we could roll these two loops together.
-    let inputsWithGAT =
-          pfoldr
-            # plam
-              ( \txInInfo' acc ->
-                  unTermCont $ do
-                    PTxInInfo txInInfo <- pmatchC txInInfo'
-                    let txOut' = pfield @"resolved" # txInInfo
-                    PValue value <- pmatchC $ pfield @"value" # txOut'
-                    pure $
-                      pmatch (plookup # gatCs # value) $ \case
-                        PNothing -> acc
-                        PJust tokenMap' -> unTermCont $ do
-                          PMap tokenMap <- pmatchC tokenMap'
-                          pure $ acc + plength # tokenMap
-              )
-            # (0 :: Term _ PInteger)
-            # txInfo.inputs
-
-    pguardC "Only one GAT must exist at the inputs" $
-      inputsWithGAT #== 1
-
     pguardC "A single authority token has been burned" $
       singleAuthorityTokenBurned gatCs txInfo.inputs txInfo.mint