5 files changed, 79 insertions, 13 deletions

diff --git a/docs/type_system/error.md b/docs/type_system/error.md
index dfe95b8..cdcf7d6 100644
--- a/docs/type_system/error.md
+++ b/docs/type_system/error.md
@@ -7,5 +7,5 @@ An error for reporting, the data used to create it cannot be accessed
 ```text
 Error
 
-e : Error $ "This is a string error"
+e : Error $ "This is an error"
 ```
diff --git a/docs/type_system/fn.md b/docs/type_system/fn.md
index 6ba8c1d..edbc04a 100644
--- a/docs/type_system/fn.md
+++ b/docs/type_system/fn.md
@@ -8,18 +8,56 @@ Fn_class `alias Enum[.partial; .complete; .iterator; .closure; .bound; .regex; .
 Fn[Fn_class; RETURN_TYPE; ARGS; STATE; List]
 ```
 
-# Returning
+## Transient Union Return
 
-## \`return
+### \`return_value
 
-## \`yield
+### \`return_error
+
+### \`return_some
+
+### \`return_none
+
+## Transient Union Return Chaining
+
+# Iterating
+
+## \`has_next
+
+## Transient Union Yield
+
+### \`yield_value
+
+### \`yield_error
+
+### \`yield_some
+
+### \`yield_none
+
+```text
+fn : Fn[x] $ ( @ 1 .. x { `yield_some 2 * x } )
+it : fn `sync 10
+// invoking
+@ it { `log v }[v] // Opton[Int[...]].v $ (.some : 2); Opton[Int[...]].v $ (.some : 4)
+// same as above
+@ `has_next it { `log it() }
+```
 
 # Calling
 
-## \`async
+## \`call_async
 
-## \`sync
+```text
+task : `call_async fn
+value : `task_wait task
+```
+
+## \`call_sync
 
 ```text
-fn `sync args // `await fn `async args
+fn `call_sync args // `task_wait fn `call_async args
 ```
+
+## \`call_native
+
+For calling native code
diff --git a/docs/type_system/overload.md b/docs/type_system/overload.md
index 142c20a..8fec210 100644
--- a/docs/type_system/overload.md
+++ b/docs/type_system/overload.md
@@ -3,3 +3,17 @@
 ---
 
 List of complete functions, selected by signature
+
+```text
+Overload[FN; ...]
+```
+
+## Example
+
+```text
+add : Overload[Fn[.native; I64; Tuple[I64.x; I64.y]; ...]; Fn[.native; F64; Tuple[F64.x; F64.y]; ...]; ...]
+
+`log add `call_native (1; 2) // Valid calls first
+`log add `call_native (1.1; 2.2) // Valid calls second
+`log add `call_native (1; 2.2) // Invalid no signature match
+```
diff --git a/docs/type_system/task.md b/docs/type_system/task.md
index 475d81a..5f8654d 100644
--- a/docs/type_system/task.md
+++ b/docs/type_system/task.md
@@ -10,4 +10,4 @@ Task_status `alias Enum[...]
 Task[Task_status; TYPE]
 ```
 
-## \`await
+## \`task_wait
diff --git a/docs/type_system/union.md b/docs/type_system/union.md
index f2c4ae0..0f8b65b 100644
--- a/docs/type_system/union.md
+++ b/docs/type_system/union.md
@@ -3,25 +3,39 @@
 ---
 
 ```text
-Union[TYPE.symbol; ...]
+Union_class `alias Enum[.container; .transient]
+
+Union[Union_class; TYPE.symbol; ...]
 ```
 
 ```text
-u : Union[I64.a; I64.b; I64.c] $ (.c : 5)
+u : Union[I64.a; I64.b; I64.c] $ (.c : 5) // defaults to Union[.container; ...]
 
 # u {
     .c { c ... }[c]
     { ... } // default
 }
 ```
+
+# Transient Unions
+
+Can only be retuned from functions and operations. The inner value must be moved out
+
 ## Alias
 
 ```text
-Result[ANY] `alias Union[ANY.value; Error.error]
+Result[ANY] `alias Union[.transient; ANY.value; Error.error]
+
+Option[ANY] `alias Union[.transient; ANY.some; Void.none]
 ```
 
-## \`take
+## Default Operation
+
+When a transient union is assigned the first type specified is moved out.
+
+If the type is not the first specified a result with an error is returned to the parent function
 
 ```text
-value : .value `take 10 / var
+z : x / y // Result[Int[...]]
+z // is value if y is not zero
 ```