Minor code restructure.

src/eval/data_check.rs

@@ -3,7 +3,7 @@
 
 use super::GlobalRuntimeState;
 use crate::types::dynamic::Union;
-use crate::{Dynamic, Engine, Position, RhaiResultOf, ERR};
+use crate::{Dynamic, Engine, Position, RhaiResult, RhaiResultOf, ERR};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 
@@ -150,4 +150,14 @@ impl Engine {
 
         Ok(())
     }
+
+    /// Check a result to ensure that it is valid.
+    #[inline]
+    pub(crate) fn check_return_value(&self, result: RhaiResult, pos: Position) -> RhaiResult {
+        if let Ok(ref r) = result {
+            self.check_data_size(r, pos)?;
+        }
+
+        result
+    }
 }

src/eval/mod.rs

@@ -22,3 +22,36 @@ pub use eval_context::EvalContext;
 pub use global_state::GlobalConstants;
 pub use global_state::GlobalRuntimeState;
 pub use target::{calc_index, calc_offset_len, Target};
+
+#[cfg(feature = "unchecked")]
+mod unchecked {
+    use crate::{eval::GlobalRuntimeState, Dynamic, Engine, Position, RhaiResult, RhaiResultOf};
+
+    impl Engine {
+        /// Check if the number of operations stay within limit.
+        #[inline(always)]
+        pub(crate) const fn track_operation(
+            &self,
+            _: &GlobalRuntimeState,
+            _: Position,
+        ) -> RhaiResultOf<()> {
+            Ok(())
+        }
+
+        /// Check whether the size of a [`Dynamic`] is within limits.
+        #[inline(always)]
+        pub(crate) const fn check_data_size(&self, _: &Dynamic, _: Position) -> RhaiResultOf<()> {
+            Ok(())
+        }
+
+        /// Check a result to ensure that it is valid.
+        #[inline(always)]
+        pub(crate) const fn check_return_value(
+            &self,
+            result: RhaiResult,
+            _: Position,
+        ) -> RhaiResult {
+            result
+        }
+    }
+}