feat: json output for uplc eval

crates/uplc/src/machine/eval_result.rs

@@ -0,0 +1,44 @@
+use crate::ast::{Constant, NamedDeBruijn, Term};
+
+use super::{cost_model::ExBudget, Error};
+
+pub struct EvalResult {
+    result: Result<Term<NamedDeBruijn>, Error>,
+    remaining_budget: ExBudget,
+    initial_budget: ExBudget,
+    logs: Vec<String>,
+}
+
+impl EvalResult {
+    pub fn new(
+        result: Result<Term<NamedDeBruijn>, Error>,
+        remaining_budget: ExBudget,
+        initial_budget: ExBudget,
+        logs: Vec<String>,
+    ) -> EvalResult {
+        EvalResult {
+            result,
+            remaining_budget,
+            initial_budget,
+            logs,
+        }
+    }
+
+    pub fn cost(&self) -> ExBudget {
+        self.initial_budget - self.remaining_budget
+    }
+
+    pub fn logs(&mut self) -> Vec<String> {
+        std::mem::take(&mut self.logs)
+    }
+
+    pub fn failed(&self) -> bool {
+        matches!(self.result, Err(_))
+            || matches!(self.result, Ok(Term::Error))
+            || matches!(self.result, Ok(Term::Constant(ref con)) if matches!(con.as_ref(), Constant::Bool(false)))
+    }
+
+    pub fn result(self) -> Result<Term<NamedDeBruijn>, Error> {
+        self.result
+    }
+}