Ki Yung Ahn kyagrd

Getting started with PureScript 0.7.x

also posted on http://kyagrd.tumblr.com/post/125748583024/getting-started-with-purescript-0710 Written based on PureScript 0.7.1.0 but shoould work with versions 0.7.0.0 and 0.7.2.0.

Some Triva about PureScript

PureScript is a purely functional language specifically targeting JavaScript as its backend. If you have tasted Haskell and lamenting about the current untyped mess in scripting languages, especially regarding web-programming, probabiy your only choice out there is PureScript.

PureScript is the only language with a sane approch to staticaly support duck typing on records by using Row Polymorphism.

	{-# LANGUAGE DeriveFunctor, RankNTypes, StandaloneDeriving #-}

	-- The Glorious Glasgow Haskell Compilation System, version 7.4.1

	data F x = C (([x] -> Bool) -> Maybe x) deriving Functor

	data F1 x = C1 ((forall y . [(y,x)] -> y) -> Maybe x) deriving Functor

	data F2 x = C2 (forall y . ([x] -> y) -> [(y,x)]) deriving Functor

	{-# OPTIONS --no-positivity-check --no-termination-check #-}

	module Mendler where

	open import Data.Bool
	-- open import Data.Product
	-- open import Data.String

	data μ (F : Set → Set) : Set where
	In : F (μ F) → μ F

	%%%% Hindley Milner + type constructor polymorphism + rank-1 kind poly
	use_module(library(apply)).
	use_module(librar(gensym)).

	:- set_prolog_flag(occurs_check,true).
	:- op(500,yfx,$).

	kind(KC,var(Z),K1) :- first(Z:K,KC), instantiate(K,K1).
	kind(KC,F $ G, K2) :- kind(KC,F,K1 -> K2), kind(KC,G,K1).
	kind(KC,A -> B,o) :- kind(KC,A,o), kind(KC,B,o).

	import Control.Monad

	type Var = Integer
	type Subst = [(Var, Term)]
	type State = (Subst, Integer)
	type Program = State -> KList State

	data Term = Atom String \| Pair Term Term \| Var Var deriving Show

	-- Apply a substitution to the top level of a term

	// 콘솔 응용 프로그램 진입점 정의

	#include "stdafx.h" // Visual C++에서 자동으로 생성해주는 녀석

	int Main(void) // 이걸 메인함수라고 생각하고 프로그래밍하면 됨
	{
	printf("hello world");
	return 0;
	}

	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width">
	<title>JS Bin</title>
	<style id="jsbin-css">
	body {
	font-size: calc(var(--font-size) * 1pt);
	}

	module pic. %% file "pic.mod"

	% eq X X.
	% neq X Y :- eq X Y => fail.

	one (inp X P) (dn X Y) (P Y).
	one (out X Y P) (up X Y) P.
	one (taup P) tau P.
	one (par P Q) A (par P1 Q) :- one P A P1.
	one (par P Q) A (par P Q1) :- one Q A Q1.

	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	</head>

	<body>
	<script id='template' style="text/template">
	<p>아래에 생성된 폼은 다음 주소로 요청을 보냅니다.
	<pre><%=url%></pre>