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//> using scala "3.2"
//> using lib "dev.zio::zio-json:0.3.0"

import zio.json.*
import zio.json.ast.Json

type T1 = (String, Int)
type T2 = (Int, String)

given JsonDecoder[T1 | T2] = 

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import tactic.basic
import category_theory.category
open category_theory

universes u v

variables {C : Type u} [category.{v} C] {X Y Z : C}


structure are_isomorph (X Y: C) :=

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val dottyVersion = "0.20.0-RC1"

lazy val root = project
  .in(file("."))
  .settings(
    name := "discipline-example",
    version := "0.1.0",
    libraryDependencies ++= Seq(
      "com.novocode" % "junit-interface" % "0.11" % "test",
      ("org.typelevel" % "cats-core_2.13" % "2.0.0").withDottyCompat(scalaVersion.value),

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object creds {
  val consumer_key    = ""
  val consumer_secret = ""
  val access_token    = ""
  val access_secret   = ""
}

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{-# LANGUAGE InstanceSigs #-}

module State where

import Control.Monad

data Estado s a = Estado { corre :: s -> (a, s) }


instance Functor (Estado s) where

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module Chap2.PictureLanguage where

-- data Painter

-- 2.2.4 Example: A Picture Language
beside :: a -> a -> a
beside a b = undefined

below :: a -> a -> a
below bottom top = undefined

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package Chap2

import scala.language.higherKinds

trait AbstractTypes {

  type Rational[A]

  def makeRat[A](x: A, y: A): Rational[A]

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def Environment[A, X](x: X) = {
  val a: A = x
  // this is safe iff X <: A
  // in other words, if we discard information 
  // (otherwise we might try to use `a` in an operation it doesn't support)
  
  // in other words: it is only safe to forget information
  
  // another form:
  def f(a: A) = {

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-- required: stack install random

import System.Random

-------- Fermat test -----------------

expmod base e m
  | e == 0 = 1
  | even e = mod (expmod base (e `div` 2) m ^ 2) m
  | otherwise = mod (base * expmod base (e - 1) m) m

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// Initial object algebra interface for expressions: integers and addition
interface ExpAlg<E> {
    lit(x: number): E
    add(e1: E, e2: E): E
}

// The evaluation interface
interface Eval {
    eval(): number
}