From 7a7e4ec0f203d5e3a25ff56b33c4a8db71ab5092 Mon Sep 17 00:00:00 2001
From: Greg Shuflin <greg.shuflin@protonmail.com>
Date: Sun, 24 Oct 2021 06:04:58 -0700
Subject: [PATCH] Use Primitive type in evaluator

---
 schala-lang/language/src/reduced_ir/mod.rs    |  2 +-
 .../language/src/tree_walk_eval/mod.rs        | 55 ++++++++++++++-----
 2 files changed, 42 insertions(+), 15 deletions(-)

diff --git a/schala-lang/language/src/reduced_ir/mod.rs b/schala-lang/language/src/reduced_ir/mod.rs
index 664b682..0a84cb6 100644
--- a/schala-lang/language/src/reduced_ir/mod.rs
+++ b/schala-lang/language/src/reduced_ir/mod.rs
@@ -288,7 +288,7 @@ pub enum Lookup {
     Param,
 }
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub enum Literal {
     Nat(u64),
     Int(i64),
diff --git a/schala-lang/language/src/tree_walk_eval/mod.rs b/schala-lang/language/src/tree_walk_eval/mod.rs
index 81f6cc9..189db57 100644
--- a/schala-lang/language/src/tree_walk_eval/mod.rs
+++ b/schala-lang/language/src/tree_walk_eval/mod.rs
@@ -59,13 +59,13 @@ fn paren_wrapped(terms: impl Iterator<Item=String>) -> String {
 
 #[derive(Debug)]
 enum RuntimeValue {
-    Expression(Expression),
     Function(FunctionDefinition),
+    Primitive(Primitive),
 }
 
-impl From<Expression> for RuntimeValue {
-    fn from(ex: Expression) -> Self {
-        Self::Expression(ex)
+impl From<Primitive> for RuntimeValue {
+    fn from(prim: Primitive) -> Self {
+        Self::Primitive(prim)
     }
 }
 
@@ -90,12 +90,40 @@ fn expr_to_repl(expr: &Expression) -> String {
 impl RuntimeValue {
     fn to_repl(&self) -> String {
         match self {
-            RuntimeValue::Expression(ref expr) => expr_to_repl(expr),
+            RuntimeValue::Primitive(ref prim) => expr_to_repl(&prim.to_expr()),
             RuntimeValue::Function(ref expr) => "<function>".to_string(),
         }
     }
 }
 
+/// A fully-reduced value
+#[derive(Debug, Clone)]
+enum Primitive {
+    Tuple(Vec<Primitive>),
+    Literal(Literal),
+    Callable(DefId),
+    Unimplemented,
+    /*
+    PrimObject {
+        name: Rc<String>,
+        tag: usize,
+        items: Vec<Node>,
+    },
+    */
+}
+
+impl Primitive {
+    fn to_expr(&self) -> Expression {
+        match self {
+            Primitive::Tuple(items) => Expression::Tuple(items.iter().map(|item| item.to_expr()).collect()),
+            Primitive::Literal(lit) => Expression::Literal(lit.clone()),
+            Primitive::Callable(defid) => Expression::Callable(Function::UserDefined(defid.clone())),
+            Primitive::Unimplemented => Expression::Unimplemented,
+        }
+    }
+}
+
+
 impl<'a> State<'a> {
     pub fn new() -> Self {
         Self {
@@ -141,25 +169,24 @@ impl<'a> State<'a> {
         }
     }
 
-  fn expression(&mut self, expression: Expression) -> EvalResult<Expression> {
+  fn expression(&mut self, expression: Expression) -> EvalResult<Primitive> {
       use Expression::Unimplemented;
       Ok(match expression {
-          lit @ Expression::Literal(_) => lit,
-          Expression::Tuple(items) => Expression::Tuple(items.into_iter().map(|expr| self.expression(expr)).collect::<EvalResult<Vec<Expression>>>()?),
+          Expression::Literal(lit) => Primitive::Literal(lit),
+          Expression::Tuple(items) => Primitive::Tuple(items.into_iter().map(|expr| self.expression(expr)).collect::<EvalResult<Vec<Primitive>>>()?),
           Expression::Lookup { ref id, kind } => {
               let mem = id.into();
               match kind {
                   Lookup::Function => {
                       if self.environments.lookup(&mem).is_some() {
-                          Expression::Callable(Function::UserDefined(id.clone()))
+                          Primitive::Callable(id.clone())
                       } else {
                           return Err(format!("Function not found for id: {}", id));
                       }
                   },
                   kind @ Lookup::LocalVar | kind @ Lookup::GlobalVar | kind @ Lookup::Param => {
                       match self.environments.lookup(&mem) {
-                          //Some(RuntimeValue::Expression(expr)) => (*expr).clone(),
-                          Some(RuntimeValue::Expression(expr)) => Unimplemented,
+                          Some(RuntimeValue::Primitive(expr)) => expr.clone(),
                           _ => return Err(format!("Nothing found for variable lookup {} of kind {:?}", id, kind)),
                       }
                   },
@@ -168,16 +195,16 @@ impl<'a> State<'a> {
           Expression::Assign { ref lval, box rval } => {
               let mem = lval.into();
               let mut env = self.environments.lookup(&mem);
-              Unimplemented
+              Primitive::Unimplemented
           },
           Expression::Call { box f, args } => self.call_expression(f, args)?,
-          Unimplemented => Unimplemented,
+          Unimplemented => Primitive::Unimplemented,
           Expression::ReductionError(e) => return Err(e.into()),
           e => return Err(format!("Can't yet handle {:?}", e)),
       })
   }
 
-  fn call_expression(&mut self, f: Expression, args: Vec<Expression>) -> EvalResult<Expression> {
+  fn call_expression(&mut self, f: Expression, args: Vec<Expression>) -> EvalResult<Primitive> {
       Err("Call expression not implemented".to_string().into())
   }
 }