Define the Tx monadic trait (#75)

* use mtl

* update to mtl 0.1.0

* update mtl to v0.1.1 and stdlib to v0.10.0

* wip

* bug

* add trait Tx

* export Tx module

* use Tx instead of Reader

Applib.juvix

@@ -2,5 +2,5 @@ module Applib;
 
 import Applib.Helpers open public;
 import Applib.Identities open public;
-
 import Applib.Authorization as Authorization public;
+import Applib.Trait.Tx open public;

Applib/Data/StandardInputs.juvix

@@ -0,0 +1,13 @@
+module Applib.Data.StandardInputs;
+
+import Stdlib.Prelude open;
+import Anoma.State open;
+import Anoma open;
+import Applib.Identities open;
+
+--- Standard inputs for Anoma transaction functions
+type StandardInputs :=
+  mkStandardInputs@{
+    caller : Identity;
+    currentRoot : CommitmentTree.Root;
+  };

Applib/Helpers.juvix

@@ -3,14 +3,17 @@ module Applib.Helpers;
 import Stdlib.Prelude open;
 import Stdlib.Debug.Fail open using {failwith};
 
+import Applib.Data.StandardInputs open public;
 import Applib.Identities open;
 import Stdlib.Data.Set as Set open using {Set; empty; insert; union; isMember};
+import Applib.Trait.Tx open public;
 import Stdlib.Data.Map as Map open using {Map};
 import Anoma open;
 import Anoma.State open;
 import Anoma.Builtin.ByteArray open;
 import Anoma.Builtin.System open;
 import BaseLayer.ResourceMachine as BaseLayer;
+import Mtl open hiding {Identity};
 
 findResourceByNullifier
   (nf : Nat) (privateInputs : BaseLayer.Witness) : Maybe Resource :=
@@ -47,14 +50,6 @@ isNullifierPresent
   (nullifier : Nullifier) (nullifierSet : Set Nullifier) : Bool :=
   Set.isMember nullifier nullifierSet;
 
---- Standard inputs for transaction functions.
---- NOTE: In the future, this will include more settings such as the information flow control flag.
-type StandardInputs :=
-  mkStandardInputs@{
-    caller : Identity;
-    currentRoot : CommitmentTree.Root;
-  };
-
 mkActionHelper
   (consumed created : List Resource) {app-data : Nat := 0} : BaseLayer.Action :=
   let
@@ -113,13 +108,19 @@ emptyTx : BaseLayer.Transaction :=
 --- @param created The created resources.
 --- @return The transaction object.
 prepareStandardTransaction
-  (standardInputs : StandardInputs)
+  {M : Type -> Type}
+  {{Tx M}}
+  {{Monad M}}
   (consumed created : List Resource)
   {app-data : Nat := 0}
-  : BaseLayer.Transaction :=
-  mkTransactionHelper@{
-    roots := [StandardInputs.currentRoot standardInputs];
-    actions := [mkActionHelper consumed created {app-data}];
+  : M BaseLayer.Transaction :=
+  do {
+    si <- getStandardInputs;
+    pure
+      mkTransactionHelper@{
+        roots := [StandardInputs.currentRoot si];
+        actions := [mkActionHelper consumed created {app-data}];
+      };
   };
 
 composeAll (txs : Set BaseLayer.Transaction) : BaseLayer.Transaction :=

Applib/Trait/Random.juvix

@@ -0,0 +1,23 @@
+module Applib.Trait.Random;
+
+import Stdlib.Prelude open;
+import Anoma.Builtin.System as Builtin;
+import Anoma open;
+import Mtl open;
+
+mkPrng (seed : Nat) : PRNG := Builtin.pseudoRandomNumberGeneratorInit seed;
+
+--- An environment capable of generating random ;ByteArray;s
+trait
+type Random (M : Type -> Type) :=
+  mkRandom@{
+    --- Returns a random ;ByteArray; of the given size
+    genRandomBytes (numBytes : Nat) : M ByteArray;
+  };
+
+instance
+StateT-Random {M : Type -> Type} {{Monad M}} : Random (StateT PRNG M) :=
+  mkRandom@{
+    genRandomBytes (n : Nat) : StateT PRNG M ByteArray :=
+      mkStateT (pseudoRandomNumberGeneratorNextBytes n >> pure);
+  };

Applib/Trait/Tx.juvix

@@ -0,0 +1,60 @@
+module Applib.Trait.Tx;
+
+import Stdlib.Prelude open;
+import Anoma open;
+import Applib.Data.StandardInputs open;
+import BaseLayer.ResourceMachine open;
+import Applib.Trait.Random open;
+import Mtl open;
+
+--- An environment used to create Anoma transactions
+trait
+type Tx (M : Type -> Type) :=
+  mkTx@{
+    --- Generates a random ;Nonce;
+    genRandomNonce : M Nonce;
+    getStandardInputs : M StandardInputs;
+  };
+
+open Tx public;
+
+module Private;
+  --- Concrete implementation of the ;Tx; trait
+  StandardTx (A : Type) : Type :=
+    StateT PRNG (ReaderT StandardInputs Mtl.Identity) A;
+
+  instance
+  StandardTx-MonadReaderI
+    : Reader
+      StandardInputs
+      (StateT PRNG (ReaderT StandardInputs Mtl.Identity)) :=
+    mkReader@{
+      ask : StandardTx StandardInputs := lift Reader.ask;
+      local
+        {A}
+        (f : StandardInputs -> StandardInputs)
+        : StandardTx A -> StandardTx A
+        | (mkStateT st) := mkStateT (st >> Reader.local f);
+    };
+
+  instance
+  StandardTx-Tx : Tx (StateT PRNG (ReaderT StandardInputs Mtl.Identity)) :=
+    mkTx@{
+      getStandardInputs : StandardTx StandardInputs := ask;
+      genRandomNonce : StandardTx Nonce :=
+        do {
+          bytes <- Random.genRandomBytes 32;
+          pure (Nonce.from32SizedByteArray bytes);
+        };
+    };
+
+  runStandardTx' {A} (seed : Nat) (si : StandardInputs) : StandardTx A -> A :=
+    evalState (mkPrng seed) >> runReader si >> Mtl.run;
+end;
+
+open Private using {StandardTx} public;
+
+--- Run the transaction builder
+runTx
+  (seed : Nat) (si : StandardInputs) : StandardTx Transaction -> Transaction :=
+  evalState (mkPrng seed) >> runReader si >> Mtl.run;

Package.juvix

@@ -6,5 +6,9 @@ package : Package :=
   defaultPackage@{
     name := "anoma-applib";
     version := mkVersion 0 6 0;
-    dependencies := [github "anoma" "juvix-stdlib" "v0.9.0"];
+    dependencies :=
+      [
+        github "anoma" "juvix-stdlib" "v0.10.0";
+        github "anoma" "juvix-mtl" "v0.1.1";
+      ];
   };

juvix.lock.yaml

@@ -2,10 +2,20 @@
 # Do not edit this file manually.
 
 version: 2
-checksum: e2a4860cbb63c726e1c85e7734bb7dc653905f2be37229bd4fe4b78d90082a22
+checksum: 88261d9c3949726f96fa44113236bd6077672f1a01902736df1da0267d43abcd
 dependencies:
 - git:
     name: anoma_juvix-stdlib
-    ref: 01ff19f1135048be3402e094f2fc89406a44a995
+    ref: c5d4fcd87b26608f628e6b116587f1ec227e1bf0
     url: https://github.com/anoma/juvix-stdlib
   dependencies: []
+- git:
+    name: anoma_juvix-mtl
+    ref: bda071b2477ff15c0292bee3dd31bc2c7d254f44
+    url: https://github.com/anoma/juvix-mtl
+  dependencies:
+  - git:
+      name: anoma_juvix-stdlib
+      ref: c5d4fcd87b26608f628e6b116587f1ec227e1bf0
+      url: https://github.com/anoma/juvix-stdlib
+    dependencies: []