diff --git a/nixide/src/expr/evalstatebuilder.rs b/nixide/src/expr/evalstatebuilder.rs
index 41c317d..d9dca5a 100644
--- a/nixide/src/expr/evalstatebuilder.rs
+++ b/nixide/src/expr/evalstatebuilder.rs
@@ -50,7 +50,7 @@ impl EvalStateBuilder {
             sys::nix_eval_state_builder_new(ctx.as_ptr(), store.as_ptr())
         })?;
 
-        sys::nix_eval_state_builder_load(context, builder);
+        // sys::nix_eval_state_builder_load(context, builder);
         // sys::nix_flake_settings_add_to_eval_state_builder(context, settings, builder);
 
         Ok(EvalStateBuilder {
diff --git a/nixide/src/expr/realised_string.rs b/nixide/src/expr/realised_string.rs
index 99f9f42..acae8c1 100644
--- a/nixide/src/expr/realised_string.rs
+++ b/nixide/src/expr/realised_string.rs
@@ -14,7 +14,7 @@ use crate::{EvalState, NixideResult, StorePath};
 pub struct RealisedString<'a> {
     inner: RefCell<NonNull<sys::nix_realised_string>>,
     pub path: StorePath,
-    pub children: LazyArray<StorePath, &'a dyn Fn(usize) -> StorePath>,
+    pub children: LazyArray<StorePath, Box<dyn Fn(usize) -> StorePath + 'a>>,
 }
 
 impl<'a> AsInnerPtr<sys::nix_realised_string> for RealisedString<'a> {
@@ -76,12 +76,13 @@ impl<'a> RealisedString<'a> {
 
         let size = unsafe { sys::nix_realised_string_get_store_path_count(inner.as_ptr()) };
 
-        let delegate = &|_| StorePath::fake_path(unsafe { state.store_ref() }).unwrap();
-
         Ok(Self {
             inner: cell,
             path: Self::parse_path(inner.as_ptr(), state),
-            children: LazyArray::new(size, &delegate),
+            children: LazyArray::new(
+                size,
+                Box::new(|_| StorePath::fake_path(unsafe { state.store_ref() }).unwrap()),
+            ),
         })
     }
 
diff --git a/nixide/src/expr/value.rs b/nixide/src/expr/value.rs
index ce7237c..d3c7d4c 100644
--- a/nixide/src/expr/value.rs
+++ b/nixide/src/expr/value.rs
@@ -7,30 +7,38 @@ use crate::sys;
 use crate::util::wrappers::AsInnerPtr;
 use crate::util::{panic_issue_call_failed, wrap};
 
+pub use crate::expr::values::{NixBool, NixFloat, NixInt, NixString, NixValue};
+
 /// A Nix value
 ///
 /// This represents any value in the Nix language, including primitives,
 /// collections, and functions.
-pub struct Value<'a> {
-    pub(crate) inner: NonNull<sys::nix_value>,
-    state: &'a EvalState,
-}
-
-impl<'a> AsInnerPtr<sys::nix_value> for Value<'a> {
-    #[inline]
-    unsafe fn as_ptr(&self) -> *mut sys::nix_value {
-        self.inner.as_ptr()
-    }
-
-    #[inline]
-    unsafe fn as_ref(&self) -> &sys::nix_value {
-        unsafe { self.inner.as_ref() }
-    }
-
-    #[inline]
-    unsafe fn as_mut(&mut self) -> &mut sys::nix_value {
-        unsafe { self.inner.as_mut() }
-    }
+///
+/// ```cpp
+/// pub const ValueType_NIX_TYPE_THUNK: ValueType = 0;
+/// pub const ValueType_NIX_TYPE_INT: ValueType = 1;
+/// pub const ValueType_NIX_TYPE_FLOAT: ValueType = 2;
+/// pub const ValueType_NIX_TYPE_BOOL: ValueType = 3;
+/// pub const ValueType_NIX_TYPE_STRING: ValueType = 4;
+/// pub const ValueType_NIX_TYPE_PATH: ValueType = 5;
+/// pub const ValueType_NIX_TYPE_NULL: ValueType = 6;
+/// pub const ValueType_NIX_TYPE_ATTRS: ValueType = 7;
+/// pub const ValueType_NIX_TYPE_LIST: ValueType = 8;
+/// pub const ValueType_NIX_TYPE_FUNCTION: ValueType = 9;
+/// pub const ValueType_NIX_TYPE_EXTERNAL: ValueType = 10;
+/// ```
+pub enum Value {
+    // Thunk(NixThunk),
+    Int(NixInt),
+    Float(NixFloat),
+    Bool(NixBool),
+    String(NixString),
+    // Path(NixPath),
+    // Null(NixNull),
+    // Attrs(NixAttrs),
+    // List(NixList),
+    // Function(NixFunction),
+    // External(NixExternal),
 }
 
 impl<'a> Value<'a> {
diff --git a/nixide/src/expr/values/bool.rs b/nixide/src/expr/values/bool.rs
index fd5598b..1b81f0f 100644
--- a/nixide/src/expr/values/bool.rs
+++ b/nixide/src/expr/values/bool.rs
@@ -13,6 +13,15 @@ pub struct NixBool {
     value: bool,
 }
 
+impl Drop for NixBool {
+    fn drop(&mut self) {
+        let ctx = ErrorContext::new();
+        unsafe {
+            sys::nix_value_decref(ctx.as_ptr(), self.as_ptr());
+        }
+    }
+}
+
 impl Display for NixBool {
     fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
         write!(f, "<bool>")
@@ -44,7 +53,7 @@ impl AsInnerPtr<sys::nix_value> for NixBool {
 
 impl NixValue for NixBool {
     #[inline]
-    fn get_enum_id(&self) -> sys::ValueType {
+    fn id(&self) -> sys::ValueType {
         sys::ValueType_NIX_TYPE_BOOL
     }
 
diff --git a/nixide/src/expr/values/float.rs b/nixide/src/expr/values/float.rs
index 84c5539..7eb8314 100644
--- a/nixide/src/expr/values/float.rs
+++ b/nixide/src/expr/values/float.rs
@@ -12,6 +12,15 @@ pub struct NixFloat {
     value: f64,
 }
 
+impl Drop for NixFloat {
+    fn drop(&mut self) {
+        let ctx = ErrorContext::new();
+        unsafe {
+            sys::nix_value_decref(ctx.as_ptr(), self.as_ptr());
+        }
+    }
+}
+
 impl Display for NixFloat {
     fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
         write!(f, "<float>")
@@ -43,7 +52,7 @@ impl AsInnerPtr<sys::nix_value> for NixFloat {
 
 impl NixValue for NixFloat {
     #[inline]
-    fn get_enum_id(&self) -> sys::ValueType {
+    fn id(&self) -> sys::ValueType {
         sys::ValueType_NIX_TYPE_FLOAT
     }
 
diff --git a/nixide/src/expr/values/int.rs b/nixide/src/expr/values/int.rs
index e9a6264..bb5ab66 100644
--- a/nixide/src/expr/values/int.rs
+++ b/nixide/src/expr/values/int.rs
@@ -12,6 +12,15 @@ pub struct NixInt {
     value: i64,
 }
 
+impl Drop for NixInt {
+    fn drop(&mut self) {
+        let ctx = ErrorContext::new();
+        unsafe {
+            sys::nix_value_decref(ctx.as_ptr(), self.as_ptr());
+        }
+    }
+}
+
 impl Display for NixInt {
     fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
         write!(f, "<int>")
@@ -43,7 +52,7 @@ impl AsInnerPtr<sys::nix_value> for NixInt {
 
 impl NixValue for NixInt {
     #[inline]
-    fn get_enum_id(&self) -> sys::ValueType {
+    fn id(&self) -> sys::ValueType {
         sys::ValueType_NIX_TYPE_INT
     }
 
diff --git a/nixide/src/expr/values/mod.rs b/nixide/src/expr/values/mod.rs
index bc503d1..8224b40 100644
--- a/nixide/src/expr/values/mod.rs
+++ b/nixide/src/expr/values/mod.rs
@@ -21,9 +21,10 @@ use std::ptr::NonNull;
 use crate::sys;
 use crate::util::wrappers::AsInnerPtr;
 
-pub trait NixValue: Display + Debug + AsInnerPtr<sys::nix_value> {
+pub trait NixValue: Drop + Display + Debug + AsInnerPtr<sys::nix_value> {
     /// TODO
-    fn get_enum_id(&self) -> sys::ValueType;
+    fn id(&self) -> sys::ValueType;
 
+    /// TODO
     fn new(inner: NonNull<sys::nix_value>) -> Self;
 }
diff --git a/nixide/src/expr/values/string.rs b/nixide/src/expr/values/string.rs
index 78fc272..d0c0f4c 100644
--- a/nixide/src/expr/values/string.rs
+++ b/nixide/src/expr/values/string.rs
@@ -3,6 +3,7 @@ use std::fmt::{Debug, Display, Formatter, Result as FmtResult};
 use std::ptr::NonNull;
 
 use super::NixValue;
+use crate::errors::ErrorContext;
 use crate::expr::RealisedString;
 use crate::util::panic_issue_call_failed;
 use crate::util::wrap;
@@ -14,6 +15,15 @@ pub struct NixString {
     value: String,
 }
 
+impl Drop for NixString {
+    fn drop(&mut self) {
+        let ctx = ErrorContext::new();
+        unsafe {
+            sys::nix_value_decref(ctx.as_ptr(), self.as_ptr());
+        }
+    }
+}
+
 impl Display for NixString {
     fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
         write!(f, "<string>")
@@ -45,7 +55,7 @@ impl AsInnerPtr<sys::nix_value> for NixString {
 
 impl NixValue for NixString {
     #[inline]
-    fn get_enum_id(&self) -> sys::ValueType {
+    fn id(&self) -> sys::ValueType {
         sys::ValueType_NIX_TYPE_STRING
     }