diff --git a/src/base/value.rs b/src/base/value.rs
index 21bf12a86..c05973b1b 100644
--- a/src/base/value.rs
+++ b/src/base/value.rs
@@ -487,6 +487,13 @@ impl<VS> Value<VS> {
         }
     }
 
+    pub fn optional(&self) -> Option<&Self> {
+        match self {
+            Value::Null => None,
+            _ => Some(self),
+        }
+    }
+
     pub fn as_bytes(&self) -> Result<&Arc<[u8]>> {
         match self {
             Value::Basic(BasicValue::Bytes(v)) => Ok(v),
diff --git a/src/ops/factory_bases.rs b/src/ops/factory_bases.rs
index c8dda8abd..c5e601ccf 100644
--- a/src/ops/factory_bases.rs
+++ b/src/ops/factory_bases.rs
@@ -25,18 +25,12 @@ pub struct ResolvedOpArg {
 }
 
 pub trait ResolvedOpArgExt: Sized {
-    type ValueType;
-    type ValueRef<'a>;
-
     fn expect_type(self, expected_type: &ValueType) -> Result<Self>;
-    fn value<'a>(&self, args: &'a Vec<value::Value>) -> Result<Self::ValueRef<'a>>;
-    fn take_value(&self, args: &mut Vec<value::Value>) -> Result<Self::ValueType>;
+    fn value<'a>(&self, args: &'a Vec<value::Value>) -> Result<&'a value::Value>;
+    fn take_value(&self, args: &mut Vec<value::Value>) -> Result<value::Value>;
 }
 
 impl ResolvedOpArgExt for ResolvedOpArg {
-    type ValueType = value::Value;
-    type ValueRef<'a> = &'a value::Value;
-
     fn expect_type(self, expected_type: &ValueType) -> Result<Self> {
         if &self.typ.typ != expected_type {
             api_bail!(
@@ -75,19 +69,24 @@ impl ResolvedOpArgExt for ResolvedOpArg {
 }
 
 impl ResolvedOpArgExt for Option<ResolvedOpArg> {
-    type ValueType = Option<value::Value>;
-    type ValueRef<'a> = Option<&'a value::Value>;
-
     fn expect_type(self, expected_type: &ValueType) -> Result<Self> {
         self.map(|arg| arg.expect_type(expected_type)).transpose()
     }
 
-    fn value<'a>(&self, args: &'a Vec<value::Value>) -> Result<Option<&'a value::Value>> {
-        self.as_ref().map(|arg| arg.value(args)).transpose()
+    fn value<'a>(&self, args: &'a Vec<value::Value>) -> Result<&'a value::Value> {
+        Ok(self
+            .as_ref()
+            .map(|arg| arg.value(args))
+            .transpose()?
+            .unwrap_or(&value::Value::Null))
     }
 
-    fn take_value(&self, args: &mut Vec<value::Value>) -> Result<Option<value::Value>> {
-        self.as_ref().map(|arg| arg.take_value(args)).transpose()
+    fn take_value(&self, args: &mut Vec<value::Value>) -> Result<value::Value> {
+        Ok(self
+            .as_ref()
+            .map(|arg| arg.take_value(args))
+            .transpose()?
+            .unwrap_or(value::Value::Null))
     }
 }
 
diff --git a/src/ops/functions/split_recursively.rs b/src/ops/functions/split_recursively.rs
index ca305508e..8288c8646 100644
--- a/src/ops/functions/split_recursively.rs
+++ b/src/ops/functions/split_recursively.rs
@@ -413,6 +413,7 @@ impl SimpleFunctionExecutor for Executor {
         let lang_config = {
             let language = self.args.language.value(&input)?;
             language
+                .optional()
                 .map(|v| anyhow::Ok(v.as_str()?.as_ref()))
                 .transpose()?
                 .and_then(|lang| TREE_SITTER_LANGUAGE_BY_LANG.get(lang))
@@ -426,6 +427,7 @@ impl SimpleFunctionExecutor for Executor {
                 .args
                 .chunk_overlap
                 .value(&input)?
+                .optional()
                 .map(|v| v.as_int64())
                 .transpose()?
                 .unwrap_or(0) as usize,