Streamline function pointers and currying.

src/module/mod.rs

@@ -425,6 +425,30 @@ impl Module {
         }
     }
 
+    /// Does the particular Rust function exist in the module?
+    ///
+    /// The `u64` hash is calculated by the function `crate::calc_fn_hash`.
+    /// It is also returned by the `set_fn_XXX` calls.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use rhai::Module;
+    ///
+    /// let mut module = Module::new();
+    /// module.set_fn_0("calc", || Ok(42_i64));
+    /// assert!(module.contains_fn_with_name("calc", true));
+    /// ```
+    #[inline]
+    #[allow(dead_code)]
+    pub(crate) fn contains_fn_with_name(&self, fn_name: &str, public_only: bool) -> bool {
+        self.functions
+            .values()
+            .filter(|(_, access, _, _, _)| !public_only || access.is_public())
+            .find(|(name, _, _, _, _)| name == fn_name)
+            .is_some()
+    }
+
     /// Set a Rust function into the module, returning a hash key.
     ///
     /// If there is an existing Rust function of the same hash, it is replaced.