added apply_params_to_script function

CHANGELOG.md

@@ -4,7 +4,8 @@
 
 ### Changed
 
-- **aiken**: Fixed overflow issue by changing `i64` to `i128` in `BigInt::Int` instances
+- **uplc**: Fixed overflow issue by changing `i64` to `i128` in `BigInt::Int` instances
+- **uplc**: Added `apply_params_to_script` function (applies params to script and serializes the new script).
 
 
 ## [v0.0.20] - 2022-10-17

crates/uplc/src/tx.rs

@@ -9,7 +9,11 @@ pub use eval::get_script_and_datum_lookup_table;
 pub use phase_one::eval_phase_one;
 use script_context::{ResolvedInput, SlotConfig};
 
-use crate::machine::cost_model::ExBudget;
+use crate::{
+    ast::{DeBruijn, Program},
+    machine::cost_model::ExBudget,
+    PlutusData,
+};
 
 pub mod error;
 mod eval;
@@ -130,3 +134,25 @@ pub fn eval_phase_two_raw(
         _ => todo!("Wrong era. Please use babbage"),
     }
 }
+
+pub fn apply_params_to_script(
+    params_bytes: &Vec<u8>, // PlutusData array
+    plutus_script_bytes: &Vec<u8>,
+) -> Result<Vec<u8>, Error> {
+    let params = match PlutusData::decode_fragment(params_bytes).unwrap() {
+        PlutusData::Array(res) => res,
+        _ => unreachable!(),
+    };
+
+    let mut buffer = Vec::new();
+    let mut program = Program::<DeBruijn>::from_cbor(plutus_script_bytes, &mut buffer)?;
+
+    for param in params {
+        program = program.apply_data(param);
+    }
+
+    match program.to_cbor() {
+        Ok(res) => Ok(res),
+        Err(_) => Err(Error::ApplyParamsError),
+    }
+}

crates/uplc/src/tx/error.rs

@@ -55,4 +55,6 @@ pub enum Error {
         index: u32,
         err: Box<Error>,
     },
+    #[error("Failed to apply parameters to Plutus script.")]
+    ApplyParamsError,
 }