package variant;

import java.util.regex.Pattern;
import java.util.Map;
import java.util.HashMap;
import java.util.Iterator;

abstract class lambda {
	abstract var f(var v);
	public var apply(var v){ return f(v); }
}

public class var {
	public static void main(String[] args){
		lambda square = new lambda(){var f(var v){
			return new $(v.i() * v.i());
		}};
		lambda say = new lambda(){var f(var v){
			System.out.println(v.display());
			return var.NIL;
		}};

		//文字列
		var name = new $("James");
		say.apply(name);

		//文字列と数値の混合リスト
		var ls = $.list(1, "2", 3, 4, 5);
		//リストの各要素を2乗したリストを返す(数値=>文字列は自動変換)
		say.apply($.map(square, ls));
		//cdr(笑)
		say.apply(ls.cdr());

		//入れ子のハッシュテーブル
		var hash = $.hash(
				"John",	$.hash("sex", "male", "age", 20),
			   	"Eva",	$.hash("sex", "female", "age", "unknown"),
			   	"Abe",	$.hash("sex", "unknown", "age", "25")
				);
		say.apply(hash.get("John").get("sex"));
		say.apply(hash.get("Nobita").get("sex"));
		say.apply(hash.keys());
		say.apply(hash);
	}

	private var_impl impl;

	public static final var NIL = new var(var_nil.NIL_IMPL);
	protected var(var_impl i){ impl = i; }

	public var(){ impl = var_nil.NIL_IMPL; }
	public var(int val){ impl = new var_int(val); }
	public var(String val){ impl = new var_str(val); }
	public var(Map<String,var> hash){ impl = new var_hash(hash); }
	public var(var car, var cdr){
		impl = (cdr.is_nil()) ? new var_list(car)
			: (cdr.is_list()) ? new var_list(car, cdr)
			: new var_pair(car, cdr);
	}

	public var car(){ return impl.car(); }
	public var cdr(){ return impl.cdr(); }
	public var get(String key){ return impl.get(key); }
	public var get(var key){ return impl.get(key.s()); }
	public var keys(){ return impl.keys(); }
	public var put(var key, var val){ return impl.put(key, val); }
	public int type(){ return impl.type(); }
	public boolean eq(var other){ return impl.eq(other.impl); }
	public boolean is_nil(){ return impl.type() == var_impl.T_NIL; }
	public boolean is_atom(){ return impl.type() != var_impl.T_LIST && impl.type() != var_impl.T_PAIR; }
	public boolean is_pair(){ return !is_atom(); }
	public boolean is_str(){ return impl.type() == var_impl.T_STR; }
	public boolean is_int(){ return impl.type() == var_impl.T_INT; }
	public boolean is_symbol(){ return impl.type() == var_impl.T_SYMBOL; }
	public boolean is_list(){ return impl.type() == var_impl.T_LIST; }
	public boolean is_hash(){ return impl.type() == var_impl.T_HASH; }
	public boolean bool(){ return impl.bool(); }

	public int i(){ return impl.i(); }
	public String s(){ return impl.s(); }
	public String display(){ return impl.display(); }
	public String toString(){ return impl.display(); }
	//static
	public static var detect(Object o){
		if(o instanceof var){
			return (var)o;
		}else if(o instanceof String){
		   	return new var((String)o);
		}else if(o instanceof Integer){
			Integer i = (Integer)o;
			return new var(i.intValue());
		}else{
			return var.NIL;
		}
	}
	public static var v(String v){ return (v==null) ? var.NIL : new var(v); }
	public static var v(int v){ return new var(v); }
	public static var v(var v){ return (v==null) ? var.NIL : v; }
}

//本当はpublicにしたいけど1ファイルにまとめるためにプリフィックスなし。
class $ extends var {
	public $(int val){ super(val); }
	public $(String val){ super(val); }

	//両方プリミティブ
	public static var cons(String car, String cdr)	{ return new var(v(car), v(cdr)); }
	public static var cons(int car, String cdr)		{ return new var(v(car), v(cdr)); }
	public static var cons(String car, int cdr)		{ return new var(v(car), v(cdr)); }
	public static var cons(int car, int cdr)		{ return new var(v(car), v(cdr)); }

	//片方プリミティブ
	public static var cons(int car, var cdr)		{ return new var(v(car), v(cdr)); }
	public static var cons(String car, var cdr)		{ return new var(v(car), v(cdr)); }
	public static var cons(var car, int cdr)		{ return new var(v(car), v(cdr)); }
	public static var cons(var car, String cdr)		{ return new var(v(car), v(cdr)); }

	//両方var
	public static var cons(var car, var cdr){ return new var(car, cdr); }


	public static var q(String exp){ return new var(new var_symbol(exp)); }

	public static var hash(Map<String,var> hash){ return new var(hash); }
	public static var hash(var list){
		Map<String, var> map = new HashMap<String,var>();
		return hash(append_hash(map, list));
	}
	public static var hash(Object... args){
		return hash(list(args));
	}
	public static Map<String,var> append_hash(Map<String,var> hash, var list){
		if( !list.cdr().is_nil() ){
			hash.put(list.car().s(), list.cdr().car());
			return append_hash(hash, list.cdr().cdr());
		}else{
			return hash;
		}
	}

	public static var list(Object... args){
		//再帰で書きたいけどきっと非効率だからやめとく。
		var ret = var.NIL;
		for(int i=args.length-1; i>-1; i--){
			Object o = args[i];
			var v = detect(o);
			ret = new var(v, ret);
		}
		return ret;
	}

	public static var map(lambda l, var list){
		if(list.is_nil()){
			return var.NIL;
		}else{
			return $.cons(l.apply(list.car()), map(l, list.cdr()));
		}
	}

}

abstract class var_impl {
	public var car(){ return var.NIL; }
	public var cdr(){ return var.NIL; }
	public var get(String key){ return var.NIL; }
	public var keys(){ return var.NIL; }
	public var put(var key, var val){ return var.NIL; }

	public abstract int type();
	public abstract String display();

	//nil 0 ""だけがfalse
	public boolean bool(){ return true; }
	public boolean eq(var_impl v){ return false; }

	public int i(){ return 0; }
	public String s(){ return ""; }

	public static final int T_NIL	= 0;
	public static final int T_INT	= 1;
	public static final int T_STR	= 2;
	public static final int T_PAIR	= 3;
	public static final int T_LIST	= 4;
	public static final int T_QUOTE	= 5;
	public static final int T_SYMBOL= 6;
	public static final int T_HASH	= 7;
}

class var_nil extends var_impl {
	private var_nil(){};
	public static final var_nil NIL_IMPL = new var_nil();

	public int type(){ return T_NIL; }
	public String display(){ return "nil"; }
	//nil 0 ""だけがfalse
	public boolean bool(){ return false; }
	public boolean eq(var_impl v){ return v.type() == T_NIL; }
}

class var_int extends var_impl {
	private int val;
	public var_int(int v){ val = v; }

	public int type(){ return T_INT; }

	public var car(){ return new var(val); }
	public int i(){ return val; }
	public String s(){ return String.valueOf(val); }
	public String display(){ return s(); }
	//nil 0 ""だけがfalse
	public boolean bool(){ return val != 0; }

	public boolean is_integer(String s){
		return Pattern.matches("^-?[0-9]+$", s);
	}

	public boolean eq(var_impl rhs){
		switch(rhs.type()){
			case T_STR :
				return (is_integer(rhs.s())) ? val == rhs.i() : false;
			case T_INT:
				return val == rhs.i();
			default:
				return false;
		}
	}
}

class var_str extends var_impl {
	private String val;
	public var_str(String v){ val = (v!=null) ? v : ""; }

	public int type(){ return T_STR; }

	public var car(){ return new var(val); }

	public int i(){ return Integer.parseInt(val); }
	public String s(){ return val; }
	public String display(){ return "\"" + val.replace("\"", "\\\"") + "\""; }
	//nil 0 ""だけがfalse
	public boolean bool(){ return !"".equals(val); }

	public boolean eq(var_impl rhs){
		switch(rhs.type()){
			case T_STR :
				return val.equals(rhs.s());
			case T_INT:
				return rhs.eq(this);
			default:
				return false;
		}
	}
}

class var_pair extends var_impl {
	private var car;
	private var cdr;
	public var_pair(var car, var cdr){
		this.car = car;
		this.cdr = cdr;
	}

	public var car(){ return car; }
	public var cdr(){ return cdr; }

	public int type(){ return T_PAIR; }
	public String s(){ return ("(" + car.display() + " . " + cdr.display() + ")"); }
	public String display(){ return s(); }

	public boolean eq(var_impl rhs){
		switch(rhs.type()){
			case T_PAIR :
				var_pair p = (var_pair)rhs;
				return car.eq(p.car) && cdr.eq(p.cdr);
			default:
				return false;
		}
	}
}

class var_list extends var_impl {
	private var car;
	private var cdr;
	public var_list(var car){
		this.car = car;
		this.cdr = var.NIL;
	}
	public var_list(var car, var cdr){
		this.car = car;
		this.cdr = cdr;
	}

	public var car(){ return car; }
	public var cdr(){ return cdr; }

	public int type(){ return T_LIST; }
	public String s(){
		return (cdr.is_nil()) ? car.display() : car.display() + " " + cdr.s();
	}
	public String display(){ return "(" + s() + ")"; }

	public boolean eq(var_impl rhs){
		switch(rhs.type()){
			case T_LIST :
				var_list p = (var_list)rhs;
				return car.eq(p.car) && cdr.eq(p.cdr);
			default:
				return false;
		}
	}
}

class var_symbol extends var_impl {
	private String val;
	public var_symbol(String v){ val = (v!=null) ? v : ""; }

	public int type(){ return T_SYMBOL; }

	public var car(){ return new var(val); }

	public int i(){ return Integer.parseInt(val); }
	public String s(){ return val; }
	public String display(){ return val; }
	//nil 0 ""だけがfalse
	public boolean bool(){ return !"".equals(val); }

	public boolean eq(var_impl rhs){
		switch(rhs.type()){
			case T_SYMBOL :
				return val.equals(rhs.s());
			default:
				return false;
		}
	}
}

class var_hash extends var_impl {
	private Map<String,var> hash;
	public var_hash(Map<String,var> hash){ this.hash = hash; }

	public int type(){ return T_HASH; }

	public var put(var key, var val){
		hash.put(key.s(), val);
		return new var(this);
	}
	public var get(var key) { return var.v(hash.get(key.car().s())); }
	public var get(String key) { return var.v(hash.get(key)); }
	public var keys(){
		var ret = var.NIL;
		Iterator<String> i = hash.keySet().iterator();
		while(i.hasNext()){
			ret = $.cons(i.next(), ret);
		}
		return ret;
	}

	public String s(){
		Iterator<String> i = hash.keySet().iterator();
		String ret = "";
		while(i.hasNext()){
			var key = new $(i.next());
			var val = hash.get(key.s());
			ret = "("+key.display()+" => "+val.display()+")" + ret;
		}
		return ret;
	}
	public String display(){ return "(" + s() + ")"; }

	public boolean eq(var_impl rhs){
		return false;
	}
}