So, I just found this and have no clue what's going on. Could you maybe make, like, a simple guide to programming ~ATH? I understand how your python works, but not how to program ~ATH.
Hi!That is sort of what this blog was meant to be.I was trying to explain how to write programs in it, starting with “how do I represent numbers in it?” but then I started prioritizing other projects.I do want to get back to this one though.Perhaps I can give a brief summary in this ask response, and you can tell me what parts you would like clarification on? I will attempt that. I would appreciate it if you tell me what parts of this explanation you are unclear on, or say more about what you don’t understand about how to use drocta ~ATH.
(drocta ~ATH, as a reminder, is my interpretation of how ~ATH could work, which attempts to stay as true to the comic as it can, while still being turing complete, and also possible to implement in reality)In drocta ~ATH there are things called objects. Every object (except for possibly one depending on the specific version of the interpreter, but that isn’t an important detail.) is initially alive. Once an object dies, it cannot be made alive again.Every object has a left half, and a right half, which are both objects. Just because an object is dead does not mean that its left or right halves are dead. Similarly, just because both an object’s left and right halves are dead does not mean that the object is dead.
Also, for any two objects (possibly the same object), there is an object such that the left half of it is the first object, and the right half of it is the second object.
(skippable sidenote : Yes, this would mean that there are infinitely many objects, but they are only /really/ created by the interpreter when they become relevant, so really there are only ever finitely many that the computer is keeping track of)
A variable, in drocta ~ATH, refers to an object. However, it often does not always refer to the same object at different points during the program.
For example, suppose you want some variable to refer to a number which changes during the program. The way that the number which the variable refers to changes is by changing what object the variable refers to.
There are two ways to change what object a variable refers to.
1:Suppose you have three variables names VAR1, VAR2, VAR3.BIFURCATE VAR1[VAR2,VAR3];will take the left half of the object that VAR1 points to, and make VAR2 point to it, instead of whatever it was pointing to before, if anything, and it takes the right half, and makes VAR3 point to it instead of whatever it was pointing to before, if anything.
2:Again, with three variables VAR1, VAR2, VAR3:BIFURCATE [VAR1,VAR2]VAR3;will take the object pointed to by VAR1, and the object pointed to by VAR2, and finds the object such that the left half is the first one, and the right half is the second one, and makes VAR3 point to this object.
Also, when you initially declare an variable it makes a new object for it.
Now, in order to make an object dead, you take a variable (named, say, examplevariable) which currently points to it, and put examplevariable.DIE();and then the object will be dead. Note that this does not make examplevariable point to a different object, which is the same as the one it pointed to before except for being dead. This actually changes the object.In fact, this is the only operation that actually changes an object.
loops:How do you do control flow with this?Well, you use ~ATH loops.
A ~ATH loop looks like this:
~ATH(SOMEVARIABLENAME){//SOME CODE GOES HERE}
What this will do, is it will check if the object currently pointed to by SOMEVARIABLENAME is dead, and if it is not, it runs the code which is {between the curly brackets}. Then, it checks again if the object currently pointed to by SOMEVARIABLENAME is dead, and if not, runs the code inside again. This keeps on repeating until a time that it checks if SOMEVARIABLENAME currently points to an object which is dead, and it is, at which point the program keeps running after the curly brackets.
Note that which object the variable name points to may be changed by the code inside the curly brackets, and probably will be. Changing which object the variable is pointing to is the main way to make the loop exit.
speaking of, let’s get to numbers:
drocta ~ATH doesn’t have numbers as a built in thing. You have to make up your own numbers. But there is a sort of standard way to do so. Where by “standard” I mean, “it is the way that makes the most sense / is the most obvious, and is the way I usually do it”
if some object is the positive integer n, then an object x which has n as the right half, and some object which is alive as the left half, then that object x is n+1 .1 is an object where the left half is a dead object, and the right half is anything.
The reason for this is because this way you can make loops which do things n times, for n>0.
say the object representing n is pointed to by VAR1 , and VAR2 doesn’t point to anything you care about, but it does point to something which is alive, and VAR3 points to an object which represents 1, but you aren’t using it for anything else. You can make a loop like this:
~ATH(VAR2){BIFURCATE VAR1[VAR2,VAR1]; //decrease VAR1 by 1BIFURCATE [VAR2,VAR3]VAR3; /* increase VAR3 by 1, except if this is the last time through the loop, in which case this makes a small error, but one which will be fixed later *///put the stuff you want in the loop here.//Don’t do things to VAR1, VAR2, or VAR3 that you don’t undo though.
}BIFURCATE VAR3[JUNK,VAR3]; //removes the extra thing that was added to VAR3.
The result of this is that it will do the code you put in the middle n times, and that VAR3 will still store the number n afterwards.
Following processes like these, it is possible to do basically anything you could with a “counter machine / minsky machine” .
Fortunately, there are also things which make things a bit more convenient than using a minsky machine.
In much the same way that you can create numbers, you can also make lists.Just put the successive entries in the list as left halfs of objects, and have the right halves be the list as made so far. (so, basically, the left half is the first element, and the right half is the rest).A caveat here is to make sure that the left half is never a dead object, because that can make it so that the end of the list is detected pre-maturely. However, you might at some point (if you write a lot of drocta ~ATH, which, I am not certain why you would, haha) find that useful to cut the remaining part of a list off.
Of course, when I say to put something as the left half or right half of an object, feel free to switch that in each case. It doesn’t matter as long as you are consistent.
oh, I left out the parts about how to do input and output .
there are some example files on the github for you to check out which have that?
Please let me know if you have any further questions. I’m not sure which parts of this need clarification, so if part of it is unclear, you would be doing me and any other readers of my blog a favor by asking me to clarify them, so please do not hesitate to ask me to clarify any specific part, or to ask me any other question about ~ATH.
Thank you for your interest,
