feat: 3 new error cases and more generic pretty printing

crates/uplc/src/machine/error.rs

@@ -1,3 +1,5 @@
+use std::fmt::Display;
+
 use thiserror::Error;
 
 use crate::ast::{NamedDeBruijn, Term};
@@ -18,4 +20,31 @@ pub enum Error {
     NonPolymorphicInstantiation(Value),
     #[error("Attempted to apply a non-function: {0:#?}")]
     NonFunctionalApplication(Value),
+    #[error("Type mismatch expected '{0}' got '{1}'")]
+    TypeMismatch(Type, Type),
+    #[error("A builtin received a term argument when something else was expected:\n\n{}\n\nYou probably forgot to wrap the builtin with a force.", .0.to_pretty())]
+    UnexpectedBuiltinTermArgument(Term<NamedDeBruijn>),
+    #[error("A builtin expected a term argument, but something else was received:\n\n{}\n\nYou probably have an extra force wrapped around a builtin", .0.to_pretty())]
+    BuiltinTermArgumentExpected(Term<NamedDeBruijn>),
+}
+
+#[derive(Debug, Clone)]
+pub enum Type {
+    Bool,
+    Integer,
+    String,
+    ByteString,
+    Unit,
+}
+
+impl Display for Type {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Type::Bool => write!(f, "bool"),
+            Type::Integer => write!(f, "integer"),
+            Type::String => write!(f, "string"),
+            Type::ByteString => write!(f, "bytestring"),
+            Type::Unit => write!(f, "unit"),
+        }
+    }
 }