Encapsulate structures.

tests/syntax.rs

@@ -27,7 +27,7 @@ fn test_custom_syntax() -> Result<(), Box<EvalAltResult>> {
             let stmt = inputs.get(1).unwrap();
             let condition = inputs.get(2).unwrap();
 
-            context.scope.push(var_name, 0 as INT);
+            context.scope_mut().push(var_name, 0 as INT);
 
             loop {
                 context.eval_expression_tree(stmt)?;
@@ -110,7 +110,7 @@ fn test_custom_syntax_raw() -> Result<(), Box<EvalAltResult>> {
         },
         1,
         |context, inputs| {
-            context.scope.push("foo", 999 as INT);
+            context.scope_mut().push("foo", 999 as INT);
 
             Ok(match inputs[0].get_variable_name().unwrap() {
                 "world" => 123 as INT,

tests/var_scope.rs

@@ -71,7 +71,7 @@ fn test_var_resolver() -> Result<(), Box<EvalAltResult>> {
             }
             // Silently maps 'chameleon' into 'innocent'.
             "chameleon" => context
-                .scope
+                .scope()
                 .get_value("innocent")
                 .map(Some)
                 .ok_or_else(|| {