feat

* remove more Rc's
* reconstruct Value::Builtin only when needed

Co-authored-by: Lucas Rosa <x@rvcas.dev>

add.uplc

@@ -1,4 +0,0 @@
-(program
-  1.0.0
-  (lam x [ [ (builtin addInteger) (con integer 1) ] x ])
-)

crates/uplc/src/machine.rs

@@ -22,13 +22,13 @@ use self::{
 enum MachineState {
     Return(Context, Value),
     Compute(Context, Env, Term<NamedDeBruijn>),
-    Done(Rc<Term<NamedDeBruijn>>),
+    Done(Term<NamedDeBruijn>),
 }
 
 #[derive(Clone)]
 enum Context {
     FrameApplyFun(Value, Box<Context>),
-    FrameApplyArg(Env, Rc<Term<NamedDeBruijn>>, Box<Context>),
+    FrameApplyArg(Env, Term<NamedDeBruijn>, Box<Context>),
     FrameForce(Box<Context>),
     NoFrame,
 }
@@ -73,7 +73,7 @@ impl Machine {
                 Compute(context, env, t) => self.compute(context, env, t)?,
                 Return(context, value) => self.return_compute(context, value)?,
                 Done(t) => {
-                    return Ok(t.as_ref().clone());
+                    return Ok(t);
                 }
             };
         }
@@ -117,7 +117,7 @@ impl Machine {
                 self.step_and_maybe_spend(StepKind::Apply)?;
 
                 Ok(MachineState::Compute(
-                    Context::FrameApplyArg(Rc::clone(&env), argument, context.into()),
+                    Context::FrameApplyArg(env.clone(), argument.as_ref().clone(), context.into()),
                     env,
                     function.as_ref().clone(),
                 ))
@@ -156,7 +156,7 @@ impl Machine {
             Context::FrameApplyArg(arg_var_env, arg, ctx) => Ok(MachineState::Compute(
                 Context::FrameApplyFun(value, ctx),
                 arg_var_env,
-                arg.as_ref().clone(),
+                arg,
             )),
             Context::FrameForce(ctx) => self.force_evaluate(*ctx, value),
             Context::NoFrame => {
@@ -188,9 +188,9 @@ impl Machine {
 
                     Ok(MachineState::Return(context, res))
                 } else {
-                    Err(Error::BuiltinTermArgumentExpected(Term::Constant(
-                        Constant::Unit.into(),
-                    )))
+                    let term = discharge::value_as_term(Value::Builtin { fun, runtime });
+
+                    Err(Error::BuiltinTermArgumentExpected(term))
                 }
             }
             rest => Err(Error::NonPolymorphicInstantiation(rest)),
@@ -216,8 +216,6 @@ impl Machine {
                 ))
             }
             Value::Builtin { fun, runtime } => {
-                // let arg_term = discharge::value_as_term(argument.clone());
-
                 if runtime.is_arrow() && !runtime.needs_force() {
                     let mut runtime = runtime;
 
@@ -231,9 +229,9 @@ impl Machine {
 
                     Ok(MachineState::Return(context, res))
                 } else {
-                    Err(Error::UnexpectedBuiltinTermArgument(Term::Constant(
-                        Constant::Unit.into(),
-                    )))
+                    let term = discharge::value_as_term(Value::Builtin { fun, runtime });
+
+                    Err(Error::UnexpectedBuiltinTermArgument(term))
                 }
             }
             rest => Err(Error::NonFunctionalApplication(rest, argument)),

crates/uplc/src/machine/discharge.rs

@@ -1,6 +1,6 @@
 use std::rc::Rc;
 
-use crate::ast::{Constant, NamedDeBruijn, Term};
+use crate::ast::{NamedDeBruijn, Term};
 
 use super::value::{Env, Value};
 
@@ -19,7 +19,7 @@ enum DischargeStep {
     PopArgStack(PartialTerm),
 }
 
-pub(super) fn value_as_term(value: Value) -> Rc<Term<NamedDeBruijn>> {
+pub(super) fn value_as_term(value: Value) -> Term<NamedDeBruijn> {
     let mut stack = vec![DischargeStep::DischargeValue(value)];
 
     let mut arg_stack = vec![];
@@ -27,9 +27,18 @@ pub(super) fn value_as_term(value: Value) -> Rc<Term<NamedDeBruijn>> {
     while let Some(stack_frame) = stack.pop() {
         match stack_frame {
             DischargeStep::DischargeValue(value) => match value {
-                Value::Con(x) => arg_stack.push(Term::Constant(x.clone()).into()),
-                Value::Builtin { .. } => {
-                    arg_stack.push(Term::Constant(Constant::Unit.into()).into())
+                Value::Con(x) => arg_stack.push(Term::Constant(x.clone())),
+                Value::Builtin { runtime, fun } => {
+                    let mut term = Term::Builtin(fun);
+
+                    for _ in 0..runtime.forces {
+                        term = term.force();
+                    }
+
+                    for arg in runtime.args {
+                        term = term.apply(value_as_term(arg));
+                    }
+                    arg_stack.push(term)
                 }
                 Value::Delay(body, env) => {
                     stack.push(DischargeStep::DischargeValueEnv(
@@ -59,14 +68,14 @@ pub(super) fn value_as_term(value: Value) -> Rc<Term<NamedDeBruijn>> {
                     let index: usize = name.index.into();
 
                     if lam_cnt >= index {
-                        arg_stack.push(Rc::new(Term::Var(name.clone())));
+                        arg_stack.push(Term::Var(name.clone()));
                     } else {
                         let env = env.get::<usize>(env.len() - (index - lam_cnt)).cloned();
 
                         if let Some(v) = env {
                             stack.push(DischargeStep::DischargeValue(v));
                         } else {
-                            arg_stack.push(Rc::new(Term::Var(name.clone())));
+                            arg_stack.push(Term::Var(name.clone()));
                         }
                     }
                 }
@@ -114,33 +123,33 @@ pub(super) fn value_as_term(value: Value) -> Rc<Term<NamedDeBruijn>> {
                     ));
                 }
                 rest => {
-                    arg_stack.push(rest.to_owned().into());
+                    arg_stack.push(rest.to_owned());
                 }
             },
             DischargeStep::PopArgStack(term) => match term {
                 PartialTerm::Delay => {
                     let body = arg_stack.pop().unwrap();
-                    arg_stack.push(Term::Delay(body).into())
+
+                    arg_stack.push(Term::Delay(body.into()))
                 }
                 PartialTerm::Lambda(parameter_name) => {
                     let body = arg_stack.pop().unwrap();
-                    arg_stack.push(
-                        Term::Lambda {
+
+                    arg_stack.push(Term::Lambda {
                         parameter_name,
-                            body,
-                        }
-                        .into(),
-                    )
+                        body: body.into(),
+                    })
                 }
                 PartialTerm::Apply => {
                     let argument = arg_stack.pop().unwrap();
                     let function = arg_stack.pop().unwrap();
 
-                    arg_stack.push(Term::Apply { function, argument }.into());
+                    arg_stack.push(function.apply(argument));
                 }
                 PartialTerm::Force => {
                     let body = arg_stack.pop().unwrap();
-                    arg_stack.push(Term::Force(body).into())
+
+                    arg_stack.push(body.force())
                 }
             },
         }

crates/uplc/src/machine/runtime.rs

@@ -23,9 +23,9 @@ use super::{
 
 #[derive(Clone, Debug)]
 pub struct BuiltinRuntime {
-    args: Vec<Value>,
+    pub(super) args: Vec<Value>,
     fun: DefaultFunction,
-    forces: u32,
+    pub(super) forces: u32,
 }
 
 impl BuiltinRuntime {