Simplify ZkappApplication

Author: sebastiencs

ledger/src/zkapps/intefaces.rs

@@ -197,6 +197,7 @@ pub trait GlobalSlotSinceGenesisInterface {
     type Bool: BoolInterface;
 
     fn equal(&self, other: &Self, w: &mut Self::W) -> Self::Bool;
+    fn exists_no_check(self, w: &mut Self::W) -> Self;
 }
 
 pub trait GlobalSlotSpanInterface {
@@ -477,7 +478,7 @@ where
     fn set_last_action_slot(&mut self, slot: Self::GlobalSlot);
 }
 
-pub trait LedgerInterface {
+pub trait LedgerInterface: LedgerIntf + Clone + ToFieldElements<Fp> {
     type W: WitnessGenerator<Fp>;
     type AccountUpdate: AccountUpdateInterface;
     type Account: AccountInterface;
@@ -567,15 +568,12 @@ pub trait ZkappApplication
 where
     Self: Sized,
 {
-    type Ledger: LedgerIntf
-        + Clone
-        + ToFieldElements<Fp>
-        + LedgerInterface<
-            W = Self::WitnessGenerator,
-            AccountUpdate = Self::AccountUpdate,
-            Account = Self::Account,
-            Bool = Self::Bool,
-        >;
+    type Ledger: LedgerInterface<
+        W = Self::WitnessGenerator,
+        AccountUpdate = Self::AccountUpdate,
+        Account = Self::Account,
+        Bool = Self::Bool,
+    >;
     type SignedAmount: SignedAmountInterface<W = Self::WitnessGenerator, Bool = Self::Bool, Amount = Self::Amount>
         + std::fmt::Debug
         + Clone
@@ -588,10 +586,11 @@ where
         SignedAmount = Self::SignedAmount,
     >;
     type Index: IndexInterface + Clone + ToFieldElements<Fp>;
-    type GlobalSlotSinceGenesis: GlobalSlotSinceGenesisInterface<W = Self::WitnessGenerator, Bool = Self::Bool>
-        + ToFieldElements<Fp>;
+    type GlobalSlotSinceGenesis: GlobalSlotSinceGenesisInterface<
+        W = Self::WitnessGenerator,
+        Bool = Self::Bool,
+    >;
     type StackFrame: StackFrameInterface<W = Self::WitnessGenerator, Calls = Self::CallForest, Bool = Self::Bool>
-        + ToFieldElements<Fp>
         + std::fmt::Debug
         + Clone;
     type CallForest: CallForestInterface<

ledger/src/zkapps/non_snark.rs

@@ -62,15 +62,12 @@ pub struct NonSnarkHandler<L>(PhantomData<L>);
 pub struct ZkappNonSnark<L>(PhantomData<L>);
 
 impl<
-        L: LedgerIntf
-            + Clone
-            + ToFieldElements<Fp>
-            + LedgerInterface<
-                W = (),
-                AccountUpdate = AccountUpdate,
-                Account = crate::Account,
-                Bool = bool,
-            >,
+        L: LedgerInterface<
+            W = (),
+            AccountUpdate = AccountUpdate,
+            Account = crate::Account,
+            Bool = bool,
+        >,
     > ZkappApplication for ZkappNonSnark<L>
 {
     type Ledger = L;
@@ -128,15 +125,12 @@ impl<F: FieldWitness> WitnessGenerator<F> for () {
 }
 
 impl<
-        L: LedgerIntf
-            + Clone
-            + ToFieldElements<Fp>
-            + LedgerInterface<
-                W = (),
-                AccountUpdate = AccountUpdate,
-                Account = crate::Account,
-                Bool = bool,
-            >,
+        L: LedgerInterface<
+            W = (),
+            AccountUpdate = AccountUpdate,
+            Account = crate::Account,
+            Bool = bool,
+        >,
     > ZkappHandler for NonSnarkHandler<L>
 {
     type Z = ZkappNonSnark<L>;
@@ -322,15 +316,12 @@ impl TokenIdInterface for TokenId {
 }
 
 impl<
-        L: LedgerIntf
-            + Clone
-            + ToFieldElements<Fp>
-            + LedgerInterface<
-                W = (),
-                AccountUpdate = AccountUpdate,
-                Account = crate::Account,
-                Bool = bool,
-            >,
+        L: LedgerInterface<
+            W = (),
+            AccountUpdate = AccountUpdate,
+            Account = crate::Account,
+            Bool = bool,
+        >,
     > LocalStateInterface for zkapp_logic::LocalState<ZkappNonSnark<L>>
 {
     type Z = ZkappNonSnark<L>;
@@ -426,11 +417,9 @@ impl GlobalSlotSinceGenesisInterface for Slot {
     fn equal(&self, other: &Self, w: &mut Self::W) -> Self::Bool {
         self == other
     }
-}
 
-impl<F: FieldWitness> ToFieldElements<F> for StackFrame {
-    fn to_field_elements(&self, fields: &mut Vec<F>) {
-        unreachable!()
+    fn exists_no_check(self, w: &mut Self::W) -> Self {
+        self
     }
 }
 

ledger/src/zkapps/snark.rs

@@ -655,6 +655,10 @@ impl GlobalSlotSinceGenesisInterface for SnarkGlobalSlot {
     fn equal(&self, other: &Self, w: &mut Self::W) -> Self::Bool {
         <Self as CheckedNat<_, 32>>::equal(self, other, w).var()
     }
+
+    fn exists_no_check(self, w: &mut Self::W) -> Self {
+        w.exists_no_check(self)
+    }
 }
 
 fn signature_verifies(

ledger/src/zkapps/zkapp_logic.rs

@@ -290,10 +290,11 @@ fn update_action_state<Z: ZkappApplication>(
         Boolean::True => s2,
         Boolean::False => s1,
     });
-    let last_action_slot = w.exists_no_check(match is_empty.as_boolean() {
+    let last_action_slot = match is_empty.as_boolean() {
         Boolean::True => last_action_slot,
         Boolean::False => txn_global_slot,
-    });
+    }
+    .exists_no_check(w);
     ([s1_new, s2, s3, s4, s5], last_action_slot)
 }