diff --git a/README.md b/README.md
index d6be399..2f8a6ff 100644
--- a/README.md
+++ b/README.md
@@ -169,29 +169,29 @@ bool empty      # => false
 Using these, you can build a lot of fundamental functional paradigm functions.
 
 ```
-:. map ?: f Any -> Any ?. x [Any] -> [Any]
+:. map : f ?. x [] -> []
 	?? bool x
 		+ f head x map 'f tail x
 		empty
-map ;y ** y 2 [1 2 3 4 5 6 7 8 9 10]  # => [1 4 9 16 25 36 49 64 81 100]
+map ;x ** x 2 [1 2 3 4 5 6 7 8 9 10]  # => [1 4 9 16 25 36 49 64 81 100]
 
-:: iterate : f i count -> [Any]
+:: iterate : f i count -> []
 	?? > count 0 
 		+ i iterate 'f f i - count 1
 		empty
 iterate ;x + 1 x 0 10  # => [0 1 2 3 4 5 6 7 8 9]
 
-:. take ?. n Int ?. x [Any] -> [Any]
+:. take ?. n Int ?. x [] -> []
 	?? > n 0
 		+ head x take - n 1 tail x
 		empty
 take 3 [1 2 3 4 5]  # => [1 2 3]
 
-:. take'while : pred Any -> Bool ?. x [Any] -> [Any]
+:. take'while ?: pred Any -> Bool ?. x [] -> []
 	?? && bool x pred head x
 		+ head x take'while 'pred tail x
 		empty
-take'while ;y < y 10 [1 3 5 7 9 11 13 15 16]  # => [1 3 5 7 9]
+take'while ;x < x 10 [1 3 5 7 9 11 13 15 16]  # => [1 3 5 7 9]
 ```
 
 ## Lambdas
diff --git a/TODO.md b/TODO.md
new file mode 100644
index 0000000..36d4bdd
--- /dev/null
+++ b/TODO.md
@@ -0,0 +1,22 @@
+
+## Internal Details
+
+- arrays as iterators instead of a vector
+- a virtual machine and bytecode
+
+## Language Features
+
+- tuples
+- `extern "C"` functions
+- modules (`import` function)
+- structs
+- data types (need an IO object for stateful functions to return)
+- unpacking type parameters (`(x:xs)` in Haskell for example)
+- type variables in function parameters and data types
+- automatic Int to Float casting if a parameter expects a float
+- `[x..y]` array generators
+- `(+)` = `;.x y + x y`
+
+## Maybe Add
+
+- `/` for float division and `//` for integer division
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
index 571aa6c..bf68de1 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,8 +5,8 @@ fn main() {
 
 	for value in runtime.values() {
 		match value {
-			Ok(v) => println!("{v}"),
-			Err(e) => eprintln!("{e}"),
+			Ok(v) => println!("=> {v}"),
+			Err(e) => eprintln!("error: {e}"),
 		}
 	}
 }