diff --git a/src/abstract_tree/function_call.rs b/src/abstract_tree/function_call.rs
index e55778b..2ecd926 100644
--- a/src/abstract_tree/function_call.rs
+++ b/src/abstract_tree/function_call.rs
@@ -88,13 +88,13 @@ impl AbstractTree for FunctionCall {
     }
 
     fn run(&self, source: &str, context: &Map) -> Result<Value> {
-        let (name, value) = match &self.function_expression {
+        let value = match &self.function_expression {
             FunctionExpression::Identifier(identifier) => {
                 let key = identifier.inner();
                 let variables = context.variables()?;
 
                 if let Some((value, _)) = variables.get(key) {
-                    (Some(key.clone()), value.clone())
+                    value.clone()
                 } else {
                     return Err(Error::FunctionIdentifierNotFound(
                         identifier.inner().clone(),
@@ -102,11 +102,11 @@ impl AbstractTree for FunctionCall {
                 }
             }
             FunctionExpression::FunctionCall(function_call) => {
-                (None, function_call.run(source, context)?)
+                function_call.run(source, context)?
             }
-            FunctionExpression::Value(value_node) => (None, value_node.run(source, context)?),
-            FunctionExpression::Index(index) => (None, index.run(source, context)?),
-            FunctionExpression::Yield(r#yield) => (None, r#yield.run(source, context)?),
+            FunctionExpression::Value(value_node) => value_node.run(source, context)?,
+            FunctionExpression::Index(index) => index.run(source, context)?,
+            FunctionExpression::Yield(r#yield) => r#yield.run(source, context)?,
         };
 
         let mut arguments = Vec::with_capacity(self.arguments.len());
@@ -117,7 +117,7 @@ impl AbstractTree for FunctionCall {
             arguments.push(value);
         }
 
-        value.as_function()?.call(name, &arguments, source, context)
+        value.as_function()?.call(&arguments, source, context)
     }
 
     fn expected_type(&self, context: &Map) -> Result<Type> {
diff --git a/src/abstract_tree/function_node.rs b/src/abstract_tree/function_node.rs
index 3d9e683..ca38adc 100644
--- a/src/abstract_tree/function_node.rs
+++ b/src/abstract_tree/function_node.rs
@@ -54,13 +54,7 @@ impl FunctionNode {
         }
     }
 
-    pub fn call(
-        &self,
-        name: Option<String>,
-        arguments: &[Value],
-        source: &str,
-        outer_context: &Map,
-    ) -> Result<Value> {
+    pub fn call(&self, arguments: &[Value], source: &str, outer_context: &Map) -> Result<Value> {
         self.context.clone_complex_values_from(outer_context)?;
 
         let parameter_argument_pairs = self.parameters.iter().zip(arguments.iter());
@@ -71,13 +65,6 @@ impl FunctionNode {
             self.context.set(key, value.clone())?;
         }
 
-        if let Some(name) = name {
-            self.context.set(
-                name,
-                Value::Function(Function::ContextDefined(self.clone())),
-            )?;
-        }
-
         let return_value = self.body.run(source, &self.context)?;
 
         Ok(return_value)
diff --git a/src/built_in_functions/string.rs b/src/built_in_functions/string.rs
index 495218e..e5baf89 100644
--- a/src/built_in_functions/string.rs
+++ b/src/built_in_functions/string.rs
@@ -298,7 +298,7 @@ impl StringFunction {
 
                 string.retain(|char| {
                     predicate
-                        .call(None, &[Value::string(char)], _source, _outer_context)
+                        .call(&[Value::string(char)], _source, _outer_context)
                         .unwrap()
                         .as_boolean()
                         .unwrap()
diff --git a/src/value/function.rs b/src/value/function.rs
index b1ae934..c95973b 100644
--- a/src/value/function.rs
+++ b/src/value/function.rs
@@ -11,19 +11,13 @@ pub enum Function {
 }
 
 impl Function {
-    pub fn call(
-        &self,
-        name: Option<String>,
-        arguments: &[Value],
-        source: &str,
-        outer_context: &Map,
-    ) -> Result<Value> {
+    pub fn call(&self, arguments: &[Value], source: &str, outer_context: &Map) -> Result<Value> {
         match self {
             Function::BuiltIn(built_in_function) => {
                 built_in_function.call(arguments, source, outer_context)
             }
             Function::ContextDefined(context_defined_function) => {
-                context_defined_function.call(name, arguments, source, outer_context)
+                context_defined_function.call(arguments, source, outer_context)
             }
         }
     }
diff --git a/src/value/mod.rs b/src/value/mod.rs
index 5026bfa..1079183 100644
--- a/src/value/mod.rs
+++ b/src/value/mod.rs
@@ -154,7 +154,7 @@ impl Value {
     }
 
     pub fn is_function(&self) -> bool {
-        matches!(self, Value::Map(_))
+        matches!(self, Value::Function(_))
     }
 
     /// Borrows the value stored in `self` as `&String`, or returns `Err` if `self` is not a `Value::String`.