add solidity verifier rust example

src/usage/solidity-verifier.md

@@ -2,7 +2,52 @@
 
 Having used the `Decider` from `decider_eth.rs`, we can now verify it in Ethereum's EVM.
 
-First we need to generate the Solidity contracts that verify the Decider proofs. Use the [solidity-verifiers-cli](https://github.com/privacy-scaling-explorations/sonobe/tree/main/cli) tool
+This can be done either by using the `solidity-verifiers-cli` or directly in rust code.
+
+## Using the CLI to generate the Solidity verifier
+Use the [solidity-verifiers-cli](https://github.com/privacy-scaling-explorations/sonobe/tree/main/cli) tool
 ```
 > solidity-verifier-cli -p nova-cyclefold -d ./folding-verifier-solidity/assets/G16_test_vk_data
 ```
+
+## Generating the Solidity verifier in rust
+Assuming that we already have our `Decider` initialized, we can now 
+
+
+```rust
+// prepare the call data
+let function_selector =
+    get_function_selector_for_nova_cyclefold_verifier(nova.z_0.len() * 2 + 1);
+let calldata: Vec<u8> = prepare_calldata(
+    function_selector,
+    nova.i,
+    nova.z_0,
+    nova.z_i,
+    &nova.U_i,
+    &nova.u_i,
+    proof,
+)
+.unwrap();
+
+// prepare the setup params for the solidity verifier
+let nova_cyclefold_vk = NovaCycleFoldVerifierKey::from((g16_vk, kzg_vk, f_circuit.state_len()));
+
+// generate the solidity code
+let decider_solidity_code = get_decider_template_for_cyclefold_decider(nova_cyclefold_vk);
+
+// verify the proof against the solidity code in the EVM
+let nova_cyclefold_verifier_bytecode = compile_solidity(&decider_solidity_code, "NovaDecider");
+let mut evm = Evm::default();
+let verifier_address = evm.create(nova_cyclefold_verifier_bytecode);
+let (_, output) = evm.call(verifier_address, calldata.clone());
+assert_eq!(*output.last().unwrap(), 1);
+
+// save smart contract and the calldata
+use std::fs;
+fs::write( "./examples/nova-verifier.sol", decider_solidity_code.clone()).unwrap();
+fs::write("./examples/solidity-calldata.calldata", calldata.clone()).unwrap();
+let s = solidity_verifiers::utils::get_formatted_calldata(calldata.clone());
+fs::write("./examples/solidity-calldata.inputs", s.join(",\n")).expect("");
+```
+
+You can find the full flow at [examples/full_flow.rs](https://github.com/privacy-scaling-explorations/sonobe/blob/main/examples/full_flow.rs).