Reduce cloning.

examples/repl.rs

@@ -141,18 +141,18 @@ fn main() {
             .compile_with_scope(&scope, &script)
             .map_err(EvalAltResult::ErrorParsing)
             .and_then(|r| {
-                ast_u = r;
+                ast_u = r.clone();
 
                 #[cfg(not(feature = "no_optimize"))]
                 {
                     engine.set_optimization_level(OptimizationLevel::Full);
-                    ast = engine.optimize_ast(&scope, &ast_u);
+                    ast = engine.optimize_ast(&scope, r);
                     engine.set_optimization_level(OptimizationLevel::None);
                 }
 
                 #[cfg(feature = "no_optimize")]
                 {
-                    ast = ast_u.clone();
+                    ast = r;
                 }
 
                 // Merge the AST into the main

src/any.rs

@@ -125,7 +125,7 @@ impl fmt::Debug for Variant {
 
 impl Clone for Dynamic {
     fn clone(&self) -> Self {
-        Any::into_dynamic(self.as_ref())
+        self.as_ref().into_dynamic()
     }
 }
 

src/api.rs

@@ -986,7 +986,7 @@ impl<'e> Engine<'e> {
     }
 
     /// Optimize the `AST` with constants defined in an external Scope.
-    /// An optimized copy of the `AST` is returned while the original `AST` is untouched.
+    /// An optimized copy of the `AST` is returned while the original `AST` is consumed.
     ///
     /// Although optimization is performed by default during compilation, sometimes it is necessary to
     /// _re_-optimize an AST. For example, when working with constants that are passed in via an
@@ -997,11 +997,11 @@ impl<'e> Engine<'e> {
     /// compiled just once. Before evaluation, constants are passed into the `Engine` via an external scope
     /// (i.e. with `scope.push_constant(...)`). Then, the `AST is cloned and the copy re-optimized before running.
     #[cfg(not(feature = "no_optimize"))]
-    pub fn optimize_ast(&self, scope: &Scope, ast: &AST) -> AST {
+    pub fn optimize_ast(&self, scope: &Scope, ast: AST) -> AST {
         optimize_into_ast(
             self,
             scope,
-            ast.0.clone(),
+            ast.0,
             ast.1.iter().map(|fn_def| fn_def.as_ref().clone()).collect(),
         )
     }

src/engine.rs

@@ -452,10 +452,11 @@ impl Engine<'_> {
 
                         scope.extend(
                             // Put arguments into scope as variables - variable name is copied
+                            // TODO - avoid copying variable name
                             fn_def
                                 .params
                                 .iter()
-                                .zip(args.iter().map(|x| (*x).into_dynamic()))
+                                .zip(args.into_iter().map(|x| (*x).into_dynamic()))
                                 .map(|(name, value)| (name.clone(), ScopeEntryType::Normal, value)),
                         );
 
@@ -481,7 +482,7 @@ impl Engine<'_> {
                             fn_def
                                 .params
                                 .iter()
-                                .zip(args.iter().map(|x| (*x).into_dynamic()))
+                                .zip(args.into_iter().map(|x| (*x).into_dynamic()))
                                 .map(|(name, value)| (name, ScopeEntryType::Normal, value)),
                         );
 
@@ -1227,6 +1228,7 @@ impl Engine<'_> {
                             *scope.get_mut(entry) = rhs_val.clone();
                             Ok(rhs_val)
                         }
+
                         ScopeSource {
                             typ: ScopeEntryType::Constant,
                             ..
@@ -1560,6 +1562,7 @@ impl Engine<'_> {
                 if let Some(type_iterators) = &self.type_iterators {
                     if let Some(iter_fn) = type_iterators.get(&tid) {
                         // Add the loop variable - variable name is copied
+                        // TODO - avoid copying variable name
                         scope.push(name.clone(), ());
 
                         let entry = ScopeSource {
@@ -1622,11 +1625,13 @@ impl Engine<'_> {
             // Let statement
             Stmt::Let(name, Some(expr), _) => {
                 let val = self.eval_expr(scope, expr, level)?;
+                // TODO - avoid copying variable name in inner block?
                 scope.push_dynamic_value(name.clone(), ScopeEntryType::Normal, val, false);
                 Ok(().into_dynamic())
             }
 
             Stmt::Let(name, None, _) => {
+                // TODO - avoid copying variable name in inner block?
                 scope.push(name.clone(), ());
                 Ok(().into_dynamic())
             }
@@ -1634,6 +1639,7 @@ impl Engine<'_> {
             // Const statement
             Stmt::Const(name, expr, _) if expr.is_constant() => {
                 let val = self.eval_expr(scope, expr, level)?;
+                // TODO - avoid copying variable name in inner block?
                 scope.push_dynamic_value(name.clone(), ScopeEntryType::Constant, val, true);
                 Ok(().into_dynamic())
             }

src/optimize.rs

@@ -480,7 +480,7 @@ fn optimize_expr<'a>(expr: Expr, state: &mut State<'a>) -> Expr {
                         // Otherwise use the default value, if any
                         def_value.clone()
                     }
-                }).and_then(|result| map_dynamic_to_expr(result, pos).0)
+                }).and_then(|result| map_dynamic_to_expr(result, pos))
                     .map(|expr| {
                         state.set_dirty();
                         expr

src/parser.rs

@@ -221,15 +221,15 @@ impl AST {
     /// # }
     /// ```
     pub fn merge(&self, other: &Self) -> Self {
-        let Self(ast, functions) = self;
+        let Self(statements, functions) = self;
 
-        let ast = match (ast.is_empty(), other.0.is_empty()) {
+        let ast = match (statements.is_empty(), other.0.is_empty()) {
             (false, false) => {
-                let mut ast = ast.clone();
+                let mut statements = statements.clone();
-                ast.extend(other.0.iter().cloned());
+                statements.extend(other.0.iter().cloned());
-                ast
+                statements
             }
-            (false, true) => ast.clone(),
+            (false, true) => statements.clone(),
             (true, false) => other.0.clone(),
             (true, true) => vec![],
         };
@@ -1733,8 +1733,8 @@ fn parse_map_literal<'a>(
                 PERR::MissingToken("}".into(), "to end this object map literal".into())
                     .into_err_eof()
             })? {
-                (Token::Identifier(s), pos) => (s.clone(), pos),
+                (Token::Identifier(s), pos) => (s, pos),
-                (Token::StringConst(s), pos) => (s.clone(), pos),
+                (Token::StringConst(s), pos) => (s, pos),
                 (_, pos) if map.is_empty() => {
                     return Err(PERR::MissingToken(
                         "}".into(),
@@ -2727,35 +2727,27 @@ pub fn parse<'a, 'e>(
 /// Map a `Dynamic` value to an expression.
 ///
 /// Returns Some(expression) if conversion is successful.  Otherwise None.
-pub fn map_dynamic_to_expr(value: Dynamic, pos: Position) -> (Option<Expr>, Dynamic) {
+pub fn map_dynamic_to_expr(value: Dynamic, pos: Position) -> Option<Expr> {
     if value.is::<INT>() {
-        let value2 = value.clone();
+        Some(Expr::IntegerConstant(value.cast(), pos))
-        (Some(Expr::IntegerConstant(value.cast(), pos)), value2)
     } else if value.is::<char>() {
-        let value2 = value.clone();
+        Some(Expr::CharConstant(value.cast(), pos))
-        (Some(Expr::CharConstant(value.cast(), pos)), value2)
     } else if value.is::<String>() {
-        let value2 = value.clone();
+        Some(Expr::StringConstant(value.cast(), pos))
-        (Some(Expr::StringConstant(value.cast(), pos)), value2)
     } else if value.is::<bool>() {
-        let value2 = value.clone();
-        (
         Some(if value.cast::<bool>() {
             Expr::True(pos)
         } else {
             Expr::False(pos)
-            }),
+        })
-            value2,
-        )
     } else {
         #[cfg(not(feature = "no_float"))]
         {
             if value.is::<FLOAT>() {
-                let value2 = value.clone();
+                return Some(Expr::FloatConstant(value.cast(), pos));
-                return (Some(Expr::FloatConstant(value.cast(), pos)), value2);
             }
         }
 
-        (None, value)
+        None
     }
 }

src/scope.rs

@@ -126,17 +126,15 @@ impl<'a> Scope<'a> {
         value: Dynamic,
         map_expr: bool,
     ) {
-        let (expr, value) = if map_expr {
-            map_dynamic_to_expr(value, Position::none())
-        } else {
-            (None, value)
-        };
-
         self.0.push(Entry {
             name: name.into(),
             typ: entry_type,
-            value,
+            value: value.clone(),
-            expr,
+            expr: if map_expr {
+                map_dynamic_to_expr(value, Position::none())
+            } else {
+                None
+            },
         });
     }
 
@@ -163,15 +161,15 @@ impl<'a> Scope<'a> {
             .find(|(_, Entry { name, .. })| name == key)
             .map(
                 |(
-                    i,
+                    index,
                     Entry {
                         name, typ, value, ..
                     },
                 )| {
                     (
                         EntryRef {
-                            name: name.as_ref(),
+                            name,
-                            index: i,
+                            index,
                             typ: *typ,
                         },
                         value.clone(),