diff --git a/library/core/src/monad copy.fe b/library/core/src/monad copy.fe
new file mode 100644
index 000000000..4f5e1e8e4
--- /dev/null
+++ b/library/core/src/monad copy.fe	
@@ -0,0 +1,173 @@
+// use self::option::Option
+
+// trait Applicative
+// where Self: * -> *
+// {
+//     fn pure<T>(t: T) -> Self<T>
+// }
+
+// impl Applicative for Option {
+//     fn pure<T>(t: T) -> Self<T> {
+//         Option::Some(t)
+//     }
+// }
+
+// trait Monad: Applicative
+// where Self: * -> *
+// {
+//     fn bind<T, F, U>(self: Self<T>) -> Self<U> where F: Fn<T, Self<U>>
+// }
+
+// impl Monad for Option {
+//     fn bind<T, F, U>(self: Self<T>) -> Self<U> where F: Fn<T, Self<U>> {
+//         match self {
+//             Self::Some(self) => F::exec(t: self)
+//             Self::None => Self::None
+//         }
+//     }
+// }
+
+// fn foo<F>(f: F)
+// where F: Fn(u8, u8, u8) -> u8 {
+// where F: Fn<{u8, u8, u8}, u8>
+
+// }
+
+// fn f(u8, u8, u8) -> u8 {} // (u8, u8, u8) -> u8
+// fn g((u8, u8, u8)) -> u8 {}  //((u8,u8,u8)) -> u8
+
+// fn main() {
+//     f(1, 2, 3) // f.exec((1, 2, 3))
+
+//     let x = (1, 2, 3)
+//     f(x)
+//     g(x)
+
+//     let args = {1, 2, 3}
+//     args.push(1)
+
+//     let args = (1, 2, 3)
+//     f (1, 2, 3)
+//     f args
+
+//     let x = ((u8, u8, u8))
+//     let x = ((u8, u8, u8),)
+
+//     f(args..) // f(x, y) f (
+// }
+// (u8, u8, u8) -> u8
+// u8 -> u8 -> u8 -> u8
+
+
+
+// impl Fn<((u8, u8, u8)), u8> for G
+
+// impl Fn<(u8, u8, u8), u8> for Foo {
+
+// }
+
+// trait Fn<T, U> where T: FnArgs {
+//     fn exect(&self, t: T) -> U
+// }
+
+// trait Fn<Arg, Ret, const Arity: usize>
+// where Arg: Tuple<Arity>
+// {
+//     fn call(self, arg : Arg) -> Ret
+// }
+
+// trait FnMut<T, U> where T: FnArgs {
+//     fn exect(&mut self, t: T) -> U
+// }
+
+// trait Tuple<const N: usize>;
+
+// fn map<T, U,F>(t: T, f: F) -> U
+// where F: Fn(T) -> U {...}
+
+// type MyFn = ()
+
+// impl<T, U> Fn<T, U> for Foo {
+//     fn exec(&self, t: T) -> U {
+//         t.element(0)
+//         t.len()
+//     }
+// }
+
+// impl Fn<(u8, u8>, Option<u8>> for MyFn {
+//     fn exec(t: (bool, bool)) -> Option<u8> {
+//         let (a, b) = t
+//         f(a, b)
+//     }
+// }
+
+// #test
+// fn my_test() {
+//     let f: MyFn = ()
+//     let a = Option::Some(true).bind<_, _, _>(f)
+//     let a: Option<u8> = Option::Some(true).bind(f)
+// }
+
+
+// sub x y = x - y
+// f = sub 1   // f 2 == 1 - 2
+// g = `sub` 1 // g 2 == 2 - 1
+
+
+// enum Result<T, E> {
+//     Ok(T)
+//     Err(E)
+// }
+// impl<E> Functor for Result<*, E> { // or Result<_, E> maybe?
+//     fn map<A, B, F: Fn<A, B>>(self: Self<A>, _ f: F) -> Self<B> {
+//         match self {
+//             Result::Ok(a) => {
+//                 return Result::Ok(f(a))
+//             }
+//             Result::Err(e) => {
+//                 return Result::Err(e)
+//             }
+//         }
+//     }
+// }
+
+
+// enum Res<E, T> { // Result<T, E>
+//     Err(E)
+//     Ok(T)
+// }
+// impl Functor for Res<MyError> {
+//     fn map<A, B, F: Fn<A, B>>(self: Self<A>, _ f: F) -> Self<B> {
+//         match self {
+//             Result::Ok(a) => {
+//                 return Result::Ok(f(a))
+//             }
+//             Result::Err(e) => {
+//                 return Result::Err(e)
+//             }
+//         }
+//     }
+// }
+
+
+
+// fn main() {
+//     let r = foo()
+//     r.map(|t| ...)
+// }
+
+
+// enum Result1<E, T>
+
+// Result<_, E>
+
+// Flip (Result)
+
+
+
+// ((+) `foldl` 0) [1..5]
+// ((`foldl` 0) [1..5]) (+)
+
+// flip :: (a -> b -> c) -> b -> a -> c
+// f :: a -> b -> c -> d -> e
+// flip f :: b -> a -> c -> d -> e
diff --git a/library/core/src/monad.fe b/library/core/src/monad.fe
index e69de29bb..ec39f6228 100644
--- a/library/core/src/monad.fe
+++ b/library/core/src/monad.fe
@@ -0,0 +1,176 @@
+use self::option::Option
+use super::num::Num
+use super::num::arith::HAdd
+
+trait Tuple<const N: u8> { }
+
+trait Fn<const Arity: u8, Args, Ret> where Args: Tuple<Arity> {
+    fn exec(self, args: Args) -> Ret
+}
+
+pub enum Option<T> {
+    Some(T),
+    None
+}
+
+trait Applicative
+where Self: * -> *
+{
+    fn pure<T>(t: T) -> Self<T>
+}
+
+impl Applicative for Option {
+    fn pure<T>(t: T) -> Self<T> {
+        Option::Some(t)
+    }
+}
+
+trait Monad: Applicative
+where Self: * -> *
+{
+    fn bind<Source, Target, Morph>(self: Self<Source>, morph: Morph) -> Self<Target>
+    where Morph: Fn<1, (Source), Self<Target>>, (Source): Tuple<1>
+}
+
+impl Monad for Option {
+    fn bind<Source, Target, Morph>(self: Self<Source>, morph: Morph) -> Self<Target>
+    where Morph: Fn<1, (Source), Self<Target>>, (Source): Tuple<1>
+    {
+        match self {
+            Self::Some(self) => morph.exec(args: (self, ))
+            Self::None => Self::None
+        }
+    }
+}
+
+struct BindAdd<N> { n: N }
+
+impl<M: * -> *, N> Fn<1, (N), M<N>> for BindAdd<N>
+where M: Monad, N: HAdd<N, N>, (N): Tuple<1>
+{
+    fn exec(self, args: (N)) -> M<N> {
+        M::pure(t: args.0.add(rhs: self.n))
+    }
+}
+
+impl<M: * -> *, N> HAdd<N, M<N>> for M<N>
+where M: Monad, N: HAdd<N, N>, (N): Tuple<1>
+{
+    fn add(self, rhs: N) -> M<N> {
+        let bind_add = BindAdd { n: rhs }
+        self.bind<N, N, BindAdd<N>>(morph: bind_add)
+    }
+}
+
+// impl HAdd<u8, Option<u8>> for Option<u8> {
+//    fn add(self, rhs: u8) -> Option<u8> {
+//        let bind_add = BindAdd { n: rhs }
+//        self.bind<u8, u8, BindAdd<u8>>(morph: bind_add)
+//    }
+// }
+
+impl Tuple<1> for (u8) { }
+
+fn test_monadd() {
+    let a: Option<u8> = Option::Some(42)
+    let b: u8 = 26
+    let c: Option<u8> = a.add(rhs: b)
+}
+
+// type MyFn = ()
+
+// impl<T> Fn<1, (bool), Option<u8>> for MyFn {
+//     fn exec(self, args: (bool)) -> Option<u8> {
+//         Option::Some(0)
+//     }
+// }
+
+// impl Tuple<1> for (bool) { }
+
+// #test
+// fn my_test() {
+//     let f: MyFn = ()
+//     let a = Option::Some(true).bind<bool, u8, MyFn>(f)
+// }
+
+// fn map<T, U,F>(t: T, f: F) -> U
+// where F: Fn(T) -> U {...}
+
+// type MyFn = ()
+
+// impl<T, U> Fn<T, U> for Foo {
+//     fn exec(&self, t: T) -> U {
+//         t.element(0)
+//         t.len()
+//     }
+// }
+
+// impl Fn<(u8, u8>, Option<u8>> for MyFn {
+//     fn exec(t: (bool, bool)) -> Option<u8> {
+//         let (a, b) = t
+//         f(a, b)
+//     }
+// }
+
+// sub x y = x - y
+// f = sub 1   // f 2 == 1 - 2
+// g = `sub` 1 // g 2 == 2 - 1
+
+
+// enum Result<T, E> {
+//     Ok(T)
+//     Err(E)
+// }
+// impl<E> Functor for Result<*, E> { // or Result<_, E> maybe?
+//     fn map<A, B, F: Fn<A, B>>(self: Self<A>, _ f: F) -> Self<B> {
+//         match self {
+//             Result::Ok(a) => {
+//                 return Result::Ok(f(a))
+//             }
+//             Result::Err(e) => {
+//                 return Result::Err(e)
+//             }
+//         }
+//     }
+// }
+
+
+// enum Res<E, T> { // Result<T, E>
+//     Err(E)
+//     Ok(T)
+// }
+// impl Functor for Res<MyError> {
+//     fn map<A, B, F: Fn<A, B>>(self: Self<A>, _ f: F) -> Self<B> {
+//         match self {
+//             Result::Ok(a) => {
+//                 return Result::Ok(f(a))
+//             }
+//             Result::Err(e) => {
+//                 return Result::Err(e)
+//             }
+//         }
+//     }
+// }
+
+
+
+// fn main() {
+//     let r = foo()
+//     r.map(|t| ...)
+// }
+
+
+// enum Result1<E, T>
+
+// Result<_, E>
+
+// Flip (Result)
+
+
+
+// ((+) `foldl` 0) [1..5]
+// ((`foldl` 0) [1..5]) (+)
+
+// flip :: (a -> b -> c) -> b -> a -> c
+// f :: a -> b -> c -> d -> e
+// flip f :: b -> a -> c -> d -> e
diff --git a/library/core/src/monad/map.fe b/library/core/src/monad/map.fe
new file mode 100644
index 000000000..e69de29bb
diff --git a/library/core/src/monad/option.fe b/library/core/src/monad/option.fe
index 418b6de81..6e8bfa479 100644
--- a/library/core/src/monad/option.fe
+++ b/library/core/src/monad/option.fe
@@ -1,4 +1,4 @@
-enum Option<Inner> {
+pub enum Option<Inner> {
     Some(Inner),
     None
 }
\ No newline at end of file
diff --git a/library/core/src/num.fe b/library/core/src/num.fe
index 715e250be..63ffeb979 100644
--- a/library/core/src/num.fe
+++ b/library/core/src/num.fe
@@ -1,19 +1,21 @@
-// use ingot::num::arith::{Add, Sub, Mul, Div, Neg, Mod, Exp}
+use ingot::num::arith::{Add, Sub, Mul, Div, Neg, Mod, Pow}
 
-// pub trait Num: Add + Sub + Mul + Div + Exp { }
+pub trait Num: Add + Sub + Mul + Div + Pow { }
 
-// pub trait Complex<N>: Num + Neg {
-//     fn re() -> N
-//     fn im() -> N
-// }
+pub trait Complex<N>: Num + Neg {
+    fn re() -> N
+    fn im() -> N
+}
 
-// pub trait Real: Num + Neg { }
+pub trait Real: Num + Neg { }
 
-// pub trait Frac<N>: Num + Neg {
-//     fn nu() -> N
-//     fn de() -> N
-// }
+pub trait Frac<N>: Num + Neg {
+    fn nu() -> N
+    fn de() -> N
+}
 
-// pub trait Int: Num + Mod + Neg { }
+pub trait Int: Num + Mod + Neg { }
 
-// pub trait Nat: Num + Mod { }
\ No newline at end of file
+pub trait Nat: Num + Mod { }
+
+impl Num for u8 { }
\ No newline at end of file
diff --git a/library/core/src/num/arith.fe b/library/core/src/num/arith.fe
index 4940e47c5..e36095349 100644
--- a/library/core/src/num/arith.fe
+++ b/library/core/src/num/arith.fe
@@ -1,77 +1,76 @@
-// /// Addition (e.g. `x + y`)
-// pub trait HAdd<Rhs, Out> {
-//     fn add(self, rhs: Rhs) -> Out
-// }
-
-// /// Subtraction (e.g. `x - y`)
-// pub trait HSub<Rhs, Out> {
-//     fn sub(self, rhs: Rhs) -> Out
-// }
-
-// /// Multiplication (e.g. `x * y`)
-// pub trait HMul<Rhs, Out> {
-//     fn mul(self, rhs: Rhs) -> Out
-// }
-
-// /// Division (e.g. `x / y`)
-// pub trait HDiv<Rhs, Out> {
-//     fn div(self, rhs: Rhs) -> Out
-// }
-
-// /// Modulo (e.g. `x % y`)
-// pub trait HMod<Rhs, Out> {
-//     fn modulo(self, rhs: Rhs) -> Out
-// }
-
-// /// Power (e.g. `x ** y`)
-// pub trait HPow<Rhs, Out> {
-//     fn pow(self, rhs: Rhs) -> Out
-// }
-
-// /// Neg (e.g. `-x`)
-// pub trait HNeg<Out> {
-//     fn neg(self) -> Out 
-// }
-
-// pub trait HMod<Rhs, Out> {
-//     fn modulo(self, rhs: Rhs) -> Out
-// }
-
-// pub trait Add: HAdd<Self, Self> { }
-
-// pub trait Sub: HSub<Self, Self> { }
-
-// pub trait Mul: HMul<Self, Self> { }
-
-// pub trait Div: HDiv<Self, Self> { }
-
-// pub trait Pow: HPow<Self, Self> { }
-
-// pub trait Mod: HMod<Self, Self> { }
-
-// pub trait Neg: HNeg<Self> { }
-
-
-// impl HAdd<Self, Self> for i8 { fn add(self, rhs: Self) -> Self { self + rhs } }
-// impl HSub<Self, Self> for i8 { fn sub(self, rhs: Self) -> Self { self - rhs } }
-// impl HMul<Self, Self> for i8 { fn mul(self, rhs: Self) -> Self { self * rhs } }
-// impl HDiv<Self, Self> for i8 { fn div(self, rhs: Self) -> Self { self / rhs } }
-// impl HNeg<Self> for i8 { fn neg(self) -> Self { -self } }
-
-// impl Add for i8 { }
-// impl Sub for i8 { }
-// impl Mul for i8 { }
-// impl Div for i8 { }
-// impl Neg for i8 { }
-
-// impl HAdd<Self, Self> for u8 { fn add(self, rhs: Self) -> Self { self + rhs } }
-// impl HSub<Self, Self> for u8 { fn sub(self, rhs: Self) -> Self { self - rhs } }
-// impl HMul<Self, Self> for u8 { fn mul(self, rhs: Self) -> Self { self * rhs } }
-// impl HDiv<Self, Self> for u8 { fn div(self, rhs: Self) -> Self { self / rhs } }
-// impl HNeg<Self> for u8 { fn neg(self) -> Self { -self } }
-
-// impl Add for u8 { }
-// impl Sub for u8 { }
-// impl Mul for u8 { }
-// impl Div for u8 { }
-// impl Neg for u8 { }
+/// Addition (e.g. `x + y`)
+pub trait HAdd<Rhs, Out> {
+    fn add(self, rhs: Rhs) -> Out
+}
+
+/// Subtraction (e.g. `x - y`)
+pub trait HSub<Rhs, Out> {
+    fn sub(self, rhs: Rhs) -> Out
+}
+
+/// Multiplication (e.g. `x * y`)
+pub trait HMul<Rhs, Out> {
+    fn mul(self, rhs: Rhs) -> Out
+}
+
+/// Division (e.g. `x / y`)
+pub trait HDiv<Rhs, Out> {
+    fn div(self, rhs: Rhs) -> Out
+}
+
+/// Modulo (e.g. `x % y`)
+pub trait HMod<Rhs, Out> {
+    fn modulo(self, rhs: Rhs) -> Out
+}
+
+/// Power (e.g. `x ** y`)
+pub trait HPow<Rhs, Out> {
+    fn pow(self, rhs: Rhs) -> Out
+}
+
+/// Neg (e.g. `-x`)
+pub trait HNeg<Out> {
+    fn neg(self) -> Out 
+}
+
+pub trait Add: HAdd<Self, Self> { }
+
+pub trait Sub: HSub<Self, Self> { }
+
+pub trait Mul: HMul<Self, Self> { }
+
+pub trait Div: HDiv<Self, Self> { }
+
+pub trait Pow: HPow<Self, Self> { }
+
+pub trait Mod: HMod<Self, Self> { }
+
+pub trait Neg: HNeg<Self> { }
+
+impl HAdd<Self, Self> for i8 { fn add(self, rhs: Self) -> Self { self + rhs } }
+impl HSub<Self, Self> for i8 { fn sub(self, rhs: Self) -> Self { self - rhs } }
+impl HMul<Self, Self> for i8 { fn mul(self, rhs: Self) -> Self { self * rhs } }
+impl HDiv<Self, Self> for i8 { fn div(self, rhs: Self) -> Self { self / rhs } }
+impl HPow<Self, Self> for i8 { fn pow(self, rhs: Self) -> Self { self ** rhs } }
+impl HNeg<Self> for i8 { fn neg(self) -> Self { -self } }
+
+impl Add for i8 { }
+impl Sub for i8 { }
+impl Mul for i8 { }
+impl Div for i8 { }
+impl Pow for i8 { }
+impl Neg for i8 { }
+
+impl HAdd<Self, Self> for u8 { fn add(self, rhs: Self) -> Self { self + rhs } }
+impl HSub<Self, Self> for u8 { fn sub(self, rhs: Self) -> Self { self - rhs } }
+impl HMul<Self, Self> for u8 { fn mul(self, rhs: Self) -> Self { self * rhs } }
+impl HDiv<Self, Self> for u8 { fn div(self, rhs: Self) -> Self { self / rhs } }
+impl HPow<Self, Self> for u8 { fn pow(self, rhs: Self) -> Self { self ** rhs } }
+impl HNeg<Self> for u8 { fn neg(self) -> Self { -self } }
+
+impl Add for u8 { }
+impl Sub for u8 { }
+impl Mul for u8 { }
+impl Div for u8 { }
+impl Pow for u8 { }
+impl Neg for u8 { }