expose some interfaces for external usage (from introduction-pods) (#256)

* expose some interfaces for external usage (from introduction-pods)

* add From<MainPod> for OperationArg, add copy op!

Co-authored-by: Eduard S. <eduardsanou@posteo.net>

---------

Co-authored-by: Eduard S. <eduardsanou@posteo.net>

book/src/merklestatements.md

@@ -39,7 +39,7 @@ all of which are represented as `MerkleTree` on the back end.
 
 The frontend compound types and their implementation as Merkle trees is explained under [POD value types](./values.md#dictionary-array-set).  The backend structure of a MerkleTree is explained on [the Merkle tree page](./merkletree.md).
 
-The POD2 interface provides statements for working with Merkle trees and compond types at all layers of the stack:
+The POD2 interface provides statements for working with Merkle trees and compound types at all layers of the stack:
 - Primitive statements for Merkle trees
 - General derived statements for Merkle trees
 - Specialized `ContainsKey`, `NotContainsKey`, and `ContainsValue` statements for the three front-end types.

src/backends/plonky2/error.rs

@@ -63,31 +63,31 @@ macro_rules! new {
 }
 use InnerError::*;
 impl Error {
-    pub(crate) fn custom(s: String) -> Self {
+    pub fn custom(s: String) -> Self {
         new!(Custom(s))
     }
-    pub(crate) fn plonky2_proof_fail(e: anyhow::Error) -> Self {
+    pub fn plonky2_proof_fail(e: anyhow::Error) -> Self {
         Self::Plonky2ProofFail(e)
     }
-    pub(crate) fn key_not_found() -> Self {
+    pub fn key_not_found() -> Self {
         new!(KeyNotFound)
     }
-    pub(crate) fn statement_not_check() -> Self {
+    pub fn statement_not_check() -> Self {
         new!(StatementNotCheck)
     }
-    pub(crate) fn repeated_value_of() -> Self {
+    pub fn repeated_value_of() -> Self {
         new!(RepeatedValueOf)
     }
-    pub(crate) fn not_type_statement() -> Self {
+    pub fn not_type_statement() -> Self {
         new!(NotTypeStatement)
     }
-    pub(crate) fn pod_id_invalid() -> Self {
+    pub fn pod_id_invalid() -> Self {
         new!(PodIdInvalid)
     }
-    pub(crate) fn id_not_equal(expected: PodId, found: PodId) -> Self {
+    pub fn id_not_equal(expected: PodId, found: PodId) -> Self {
         new!(IdNotEqual(expected, found))
     }
-    pub(crate) fn type_not_equal(expected: PodType, found: Value) -> Self {
+    pub fn type_not_equal(expected: PodType, found: Value) -> Self {
         new!(TypeNotEqual(expected, found))
     }
 }

src/backends/plonky2/mainpod/mod.rs

@@ -39,7 +39,7 @@ use crate::{
 /// `max_public_statements` only pay for `max_public_statements` by starting the poseidon state
 /// with a precomputed constant corresponding to the front-padding part:
 /// `id = hash(serialize(reverse(statements || none-statements)))`
-pub(crate) fn calculate_id(statements: &[Statement], params: &Params) -> middleware::Hash {
+pub fn calculate_id(statements: &[Statement], params: &Params) -> middleware::Hash {
     assert!(statements.len() <= params.num_public_statements_id);
     assert!(params.max_public_statements <= params.num_public_statements_id);
 
@@ -409,7 +409,7 @@ impl Prover {
     fn _prove(&self, params: &Params, inputs: MainPodInputs) -> Result<MainPod> {
         let rec_circuit_data = &*STANDARD_REC_MAIN_POD_CIRCUIT_DATA;
         let (main_pod_target, circuit_data) =
-            RecursiveCircuit::<MainPodVerifyTarget>::circuit_data_padded(
+            RecursiveCircuit::<MainPodVerifyTarget>::target_and_circuit_data_padded(
                 params.max_input_recursive_pods,
                 &rec_circuit_data.common,
                 params,
@@ -570,7 +570,8 @@ impl MainPod {
         let rec_circuit_data = &*STANDARD_REC_MAIN_POD_CIRCUIT_DATA;
         // TODO: cache these artefacts
         // https://github.com/0xPARC/pod2/issues/247
-        let (_, circuit_data) = RecursiveCircuit::<MainPodVerifyTarget>::circuit_data_padded(
+        let (_, circuit_data) =
+            RecursiveCircuit::<MainPodVerifyTarget>::target_and_circuit_data_padded(
                 self.params.max_input_recursive_pods,
                 &rec_circuit_data.common,
                 &self.params,

src/backends/plonky2/recursion/circuit.rs

@@ -113,7 +113,7 @@ pub fn new_params_padded<I: InnerCircuit>(
     inner_params: &I::Params,
 ) -> Result<RecursiveParams> {
     let (_, circuit_data) =
-        RecursiveCircuit::<I>::circuit_data_padded(arity, common_data, inner_params)?;
+        RecursiveCircuit::<I>::target_and_circuit_data_padded(arity, common_data, inner_params)?;
     let common_data = circuit_data.common.clone();
     let verifier_data = circuit_data.verifier_data();
     Ok(RecursiveParams {
@@ -265,7 +265,7 @@ impl<I: InnerCircuit> RecursiveCircuit<I> {
     }
 
     /// returns the full-recursive CircuitData padded to share the input `common_data`
-    pub fn circuit_data_padded(
+    pub fn target_and_circuit_data_padded(
         arity: usize,
         common_data: &CommonCircuitData<F, D>,
         inner_params: &I::Params,
@@ -688,7 +688,7 @@ mod tests {
         let common_data = &circuit_data_3.common;
 
         let (_, circuit_data_1) =
-            RC::<Circuit1>::circuit_data_padded(arity, &common_data, &inner_params)?;
+            RC::<Circuit1>::target_and_circuit_data_padded(arity, &common_data, &inner_params)?;
         let params_1 = RecursiveParams {
             arity,
             common_data: circuit_data_1.common.clone(),
@@ -696,7 +696,7 @@ mod tests {
         };
 
         let (_, circuit_data_2) =
-            RC::<Circuit2>::circuit_data_padded(arity, &common_data, &inner_params)?;
+            RC::<Circuit2>::target_and_circuit_data_padded(arity, &common_data, &inner_params)?;
         let params_2 = RecursiveParams {
             arity,
             common_data: circuit_data_2.common.clone(),

src/frontend/mod.rs

@@ -645,6 +645,22 @@ impl MainPod {
     pub fn id(&self) -> PodId {
         self.pod.id()
     }
+
+    /// Returns the value of a ValueOf statement with self id that defines key if it exists.
+    pub fn get(&self, key: impl Into<Key>) -> Option<Value> {
+        let key: Key = key.into();
+        self.public_statements
+            .iter()
+            .find_map(|st| match st {
+                Statement::ValueOf(ak, value)
+                    if ak.pod_id == self.id() && ak.key.hash() == key.hash() =>
+                {
+                    Some(value)
+                }
+                _ => None,
+            })
+            .cloned()
+    }
 }
 
 struct MainPodCompilerInputs<'a> {
@@ -759,6 +775,9 @@ pub mod build_utils {
         (new_entry, ($key:expr, $value:expr)) => { $crate::frontend::Operation(
             $crate::middleware::OperationType::Native($crate::middleware::NativeOperation::NewEntry),
             $crate::op_args!(($key, $value)), $crate::middleware::OperationAux::None) };
+        (copy, $($arg:expr),+) => { $crate::frontend::Operation(
+            $crate::middleware::OperationType::Native($crate::middleware::NativeOperation::CopyStatement),
+            $crate::op_args!($($arg),*), $crate::middleware::OperationAux::None) };
         (eq, $($arg:expr),+) => { $crate::frontend::Operation(
             $crate::middleware::OperationType::Native($crate::middleware::NativeOperation::EqualFromEntries),
             $crate::op_args!($($arg),*), $crate::middleware::OperationAux::None) };

src/frontend/operation.rs

@@ -1,7 +1,7 @@
 use std::fmt;
 
 use crate::{
-    frontend::SignedPod,
+    frontend::{MainPod, SignedPod},
     middleware::{AnchoredKey, OperationAux, OperationType, Statement, Value},
 };
 
@@ -78,6 +78,18 @@ impl From<(&SignedPod, &str)> for OperationArg {
         ))
     }
 }
+impl From<(&MainPod, &str)> for OperationArg {
+    fn from((pod, key): (&MainPod, &str)) -> Self {
+        // TODO: TryFrom.
+        let value = pod
+            .get(key)
+            .unwrap_or_else(|| panic!("Key {} is not present in POD: {}", key, pod));
+        Self::Statement(Statement::ValueOf(
+            AnchoredKey::from((pod.id(), key)),
+            value,
+        ))
+    }
+}
 
 impl From<Statement> for OperationArg {
     fn from(s: Statement) -> Self {