gavrilovmiroslav

// recursion schemes in c++: implement `map`, get `fold` for free!

// author: Maxime Tournier
// date: November 2019
// license: MIT

// TODO:
// - anamorphisms, hylomorphisms & friends
// - handle bi-functors gracefully (not clear whether the usual list functor can 
//   be implemented together with the one presented here)

gavrilovmiroslav

using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;

namespace GMPool
{
    public class Pool<T> : IEnumerable<T> where T : class, new()
    {

gavrilovmiroslav

You might know some or all of this introduction but here's all of it for pedantic reasons. So, there's this thing called multiplicative persistence, which is basically the count of times a number can be reduced by multiplying its digits together until the result is a single digit number. For example, 89 has an MP of 3 because it takes three steps to reduce it to a single digit number:

89
8*9 = 72
7*2 = 14
1*4 = 4

Now, if you take some time to investigate, it turns out that many numbers fail at having a high MP rather quickly: they devolve because at some point 2 and 5 meet and form a 10, and that zero is a sink. Multiplying with 1 keeps the score, but reduces the number of digits available for the next step; all of this rings to me like either a structure (group maybe) or an extension on the ring of natural numbers, but I'm not sure about it yet. At any rate, the highest MP ever found is 11. It isn't proven that that is the highest possible, but extensive checking suggests it. One such number is 277

gavrilovmiroslav

<!-- a template defining three nested template calls -->
<template id='three-hellos'>
	<!-- first hello is missing a surname -->
	<hello-world data-name="Mark"></hello-world>
	<hello-world data-name="Sue" data-surname="Sanders"></hello-world>
	<hello-world data-name="Derek" data-surname="Dickens"></hello-world>
</template>

<!-- a hello world template that writes a hello message -->
<template id='hello-world'>

gavrilovmiroslav

object Ascii {
	val asciiToUnicode = Array(
	//       0       1       2       3       4       5       6       7       8       9       a       b       c       d       e       f	  
		0x0000, 0x263a, 0x263b, 0x2665, 0x2666, 0x2663, 0x2660, 0x2022, 0x25d8, 0x25cb, 0x25d9, 0x2642, 0x2640, 0x266a, 0x266b, 0x263c,	// 0
		0x25ba, 0x25c4, 0x2195, 0x203c, 0x00b6, 0x00a7, 0x25ac, 0x21a8, 0x2191, 0x2913, 0x2192, 0x2190, 0x221f, 0x2194, 0x25b2, 0x25bc, // 1
		0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0025, 0x0026, 0x0027, 0x0028, 0x0029, 0x002a, 0x002b, 0x002c, 0x002d, 0x002e, 0x002f, // 2
		0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037, 0x0038, 0x0039, 0x003a, 0x003b, 0x003c, 0x003d, 0x003e, 0x003f, // 3
		0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047, 0x0048, 0x0049, 0x004a, 0x004b, 0x004c, 0x004d, 0x004e, 0x004f, // 4
		0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057, 0x0058, 0x0059, 0x005a, 0x005b, 0x005c, 0x005d, 0x005e, 0x005f, // 5
		0x0060, 0x0061, 0x0062, 0x0063, 0

gavrilovmiroslav

#include <type_traits>
#include <iostream>

struct Base
{
	void x()
	{
		std::cout << "X called from parent! " << std::endl;
	}	
};

gavrilovmiroslav

	// a -> a' <=> a -> [a]
	// a -> 'a <=> for quotes, [a] -> a; 
				   for values, 'a == a

	// linear
	// #rhs ≤ #lhs
	zap  	:: a ->
	i	:: a -> 'a
	unit 	:: a -> a'

gavrilovmiroslav

Hey, Lucas, sorry for bothering you over the weekend, I wanted to pass an idea along, to see whether you think we could maybe use something from it. I'll try to explain it on a simple example function in some weird labelled quasijava:

a: input = INPUT();
if(input > 1000) 
b:  return CALCULATION();
do {
c:  input += 7;
d:  RANDOM_LONG_CODE();
} until(input <72);
e: return input;

gavrilovmiroslav

Based on our records and DHCP here are the VLAB machines
Managed computers are named after musical instruments

piano - server
bass  
banjo
drum
guitar

Unmanaged Ubuntu computers are named after carving tools

gavrilovmiroslav

> run
[info] Compiling 1 Scala source to C:\Users\Pandora\.babun\cygwin\home\Pandora\pkmn\target\scala-2.10\classes...
[warn] there were 1 feature warning(s); re-run with -feature for details
[warn] one warning found
[info] Running Main
Player(
  mika,
  Prizes(List(squirtle, water, level ball, water, water, level ball)),
  Hand(List(keldeo, squirtle, water, water, keldeo, level ball, keldeo)),
  Active(None),