Praiku

2016-11-19, post № 147

art, haiku, mathematics, poetry, programming, Python, #prime

brainfuck

2016-11-05, post № 146

brainfuck, programming, Python, #esoteric, #interpreter, #minimalism

Usually, programming languages are designed to be efficient, understandable and usable. Their concepts are well thought-out, giving the programmer powerful tools to create their application.
Esoteric programming languages have a slightly different aim. Instead of focusing on the product, they focus on the programmer’s journey and try new approaches to building a program.
One well-known esoteric programming language is Urban Müller’s brainfuck. It is a Turing-complete programming language — meaning that it could with infinite memory do what a Turing machine can do —, which practices extreme minimalism. The language knows of only eight characters (<>+-[].,).
The language’s usage is very similar to a Turing machine. Starting the program, the pointer is at cell zero and can be moved left (<) or right (>) by one cell.
The cells’ values are all starting at 𝟢, but can be either increased (+) or decreased (-) by one. Because the cells can only store one unsigned byte, adding one to 𝟤𝟧𝟧 yields in 𝟢 and subtracting one from 𝟢 yields in 𝟤𝟧𝟧.
Also, a loop is possible by using square brackets. An open square bracket ([) starts a loop and a closed square bracket (]) ends a loop. When the end of a loop is reached, the interpreter will jump back to its start if and only if the currently selected cell’s value is 𝟢.^[1]
The only way to communicate with the user is to print the currently selected cell’s ASCII character to the screen (.) and get a user input which will be stored in the currently selected cell as its ASCII value (,).

Because of its minimalistic design, writing an interpreter is not particularly hard. Listed below is the Python code of my interpreter, which I used to execute my own brainfuck “Hello World.” program (𝟣𝟣𝟪 characters).
Online interpreters include for example bf.doleczek.pl and sange.fi.

Useful Wikipedia articles include Esoteric Programming Language, Brainfuck and Turing Machine.

$ python brainfuck.py
Hello World.

Halloween MMXVI

2016-10-31, post № 145

art, poetry, #horror, #purple cube, #sea, #story

99 Bottles of Beer

2016-10-22, post № 144

art, codegolf, poetry, programming, Pygame, #character-sparse code, #characters, #space-efficient, #StackExchange

I recently^[1] found a five year old StackExchange thread talking about a programming challenge to recreate the marvelously imaginative lyrics of ‘99 Bottles of Beer’. The song goes as follows (whole lyrics can be viewed below).

Of course, the real challenge is not to build a program that generates the lyrics but rather to do it with the least amount of characters^[2]. To achieve this goal, I tried out various strategies, all written in Python.

The first strategy is to join a string generated by a for loop (𝟤𝟨𝟥 characters).

a,b=" bottles of beer"," on the wall"
c=a.replace("s","")
print"\n".join([str(n)+a+b+", "+str(n)+a+"."+"\nTake one down and pass it around, "+str(n-1)+[a,c][n<3]+b+".\n"for n in range(99,1,-1)])+"\n1"+c+b+", 1"+c+".\nGo to the store and buy some more, 99"+a+b+"."

The second, less efficient strategy is to use a function and recursion (𝟤𝟩𝟦 characters).

a,b=" bottles of beer"," on the wall"
c=a.replace("s","")
def f(n):
	s=""
	if n>1:
		s="%d"%n+a+b+", %d"%n+a+".\nTake one down and pass it around, "+str(n-1)+[c,a][n>2]+b+".\n\n"+f(n-1)
	return s
print f(99)+"1"+c+b+", 1"+c+".\nGo to the store and buy some more, 99"+a+b+"."

The third is a bit more character-efficient, using lambda functions and recursion (𝟤𝟩𝟢 characters).

a="%d bottle%s of beer"
b=" on the wall"
c=["","s"]
f=lambda i:a%(i,c[i>1])+b+", "+a%(i,c[i>1])+".\nTake one down and pass it around, "+a%(i-1,c[i>2])+b+".\n\n"
F=lambda i:f(i)+F(i-1)if i>0 else ""
print F(99)[:-65]+"Go to the store and buy some more, "+a%(99,"s")+b+"."

The fourth, final and most space-efficient^[3] strategy is to use a while loop (𝟤𝟧𝟢 characters).

a="%d bottle%s of beer"
b=" on the wall"
c=a+b+", "+a+"."
i=99
s=""
while i>1:s+=c%((i,"s")*2);i-=1;s+="\nTake one down and pass it around, "+a%(i,["","s"][i>1])+b+".\n\n"
print s+c%(1,"",1,"")+"\nGo to the store and buy some more, "+a%(99,"s")+b+"."

Menger Sponge II

2016-10-08, post № 143

Processing 3, programming, Python, #3D, #fractal, #three dimensions, #three-D, #three-dimensional

In July of 2015 I published my Menger Sponge post. As I said there, the true Menger Sponge is a three-dimensional object, but due to the lack of 3D-integration in Pygame, I only showed one of the six cube’s faces. The two-dimensional fractal is officially called Sierpiński carpet while the three-dimensional object is really called a Menger sponge.
To achieve the three-dimensional cube, I used Processing 3 together with its Python Mode.
The actual fractal is colored with a pseudo-randomly chosen color. All its smaller cubes then get a slight color shift. The cube rotates slowly, with a different speed on each of the three axes.

Microcounter

2016-09-24, post № 142

MicroPython, programming, Python 3, #micro, #microcontroller, #pyboard

Being a big fan of Python^[1], I recently got a MicroPython Board.
MicroPython is a simple to use micro controller which runs Python 3. To put code onto it, you simple mount it as you would do with a USB flash drive, copy your main.py to it and restart your MicroPython.
As a simple “Hello world.”-program, I wrote this counting script. Every time you press the built-in^[2] button, it counts up by one. Using the four built-in LEDs and binary number representation, this counter can count from 𝟢 to 𝟣𝟧 and then wraps back.

J-Trix

2016-09-10, post № 141

curses, programming, Python, #animation, #bit, #bits, #falling bits, #hacker, #hacking, #Matrix, #screensaver

Recreating the famous falling bit effect from Matrix using python and curses.The individual bit strips are separate entities, falling to the bottom and then being moved up again with a different 𝑥 value. They also get a random speed between one and five deciseconds.

Collatz Conjecture

2016-09-03, post № 140

mathematics, programming, Pygame, Python, #3n+1, #three n plus one

The Collatz conjecture states that every positive integer 𝑘 > 𝟢 will — if you iteratively set 𝑘 to 𝑓 (𝑘) — result in 𝟣 (function shown beneath).
The graph beneath shows the path length of numbers from 𝟣 to 𝟣𝟢 𝟢𝟢𝟢. In this range, 𝟨 𝟣𝟩𝟢 is the number with the most steps, 𝟤𝟨𝟣.