Add tag to Dynamic.

src/packages/lang_core.rs

@@ -0,0 +1,45 @@
+use crate::def_package;
+use crate::dynamic::Tag;
+use crate::plugin::*;
+use crate::{Dynamic, EvalAltResult, INT};
+#[cfg(feature = "no_std")]
+use std::prelude::v1::*;
+
+#[export_module]
+mod core_functions {
+    #[rhai_fn(name = "tag", get = "tag", pure)]
+    pub fn get_tag(value: &mut Dynamic) -> INT {
+        value.tag() as INT
+    }
+    #[rhai_fn(name = "set_tag", set = "tag", return_raw)]
+    pub fn set_tag(value: &mut Dynamic, tag: INT) -> Result<(), Box<EvalAltResult>> {
+        if tag < Tag::MIN as INT {
+            Err(Box::new(EvalAltResult::ErrorArithmetic(
+                format!(
+                    "{} is too small to fit into a tag (must be between {} and {})",
+                    tag,
+                    Tag::MIN,
+                    Tag::MAX
+                ),
+                Position::NONE,
+            )))
+        } else if tag > Tag::MAX as INT {
+            Err(Box::new(EvalAltResult::ErrorArithmetic(
+                format!(
+                    "{} is too large to fit into a tag (must be between {} and {})",
+                    tag,
+                    Tag::MIN,
+                    Tag::MAX
+                ),
+                Position::NONE,
+            )))
+        } else {
+            value.set_tag(tag as Tag);
+            Ok(())
+        }
+    }
+}
+
+def_package!(crate:LanguageCorePackage:"Language core functions.", lib, {
+    combine_with_exported_module!(lib, "language_core", core_functions);
+});

src/packages/mod.rs

@@ -6,6 +6,7 @@ pub(crate) mod arithmetic;
 mod array_basic;
 mod fn_basic;
 mod iter_basic;
+mod lang_core;
 mod logic;
 mod map_basic;
 mod math_basic;
@@ -86,6 +87,7 @@ macro_rules! def_package {
         }
 
         impl $package {
+            #[allow(dead_code)]
             pub fn new() -> Self {
                 let mut module = $root::Module::new();
                 <Self as $root::packages::Package>::init(&mut module);

src/packages/pkg_core.rs

@@ -1,6 +1,7 @@
 use super::arithmetic::ArithmeticPackage;
 use super::fn_basic::BasicFnPackage;
 use super::iter_basic::BasicIteratorPackage;
+use super::lang_core::LanguageCorePackage;
 use super::logic::LogicPackage;
 use super::string_basic::BasicStringPackage;
 #[cfg(feature = "no_std")]
@@ -9,6 +10,7 @@ use std::prelude::v1::*;
 use crate::def_package;
 
 def_package!(crate:CorePackage:"_Core_ package containing basic facilities.", lib, {
+    LanguageCorePackage::init(lib);
     ArithmeticPackage::init(lib);
     LogicPackage::init(lib);
     BasicStringPackage::init(lib);