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Programming and Electronics
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File: 1581460038602.png (503.48 KB, 934x1000, daily_programming.png)

 No.211

What are you working on, /g/?

 No.216

I'm really sorry about textboard.org but Bitdiddle said the stress tests were badly needed and kept encouraging me. I hope it's back up soon.

 No.217

File: 1582269064422.jpg (160.42 KB, 800x998, marika_kato__bodacious_spa….jpg)

>>216
It seems to have returned from death.



Why are you testing in production?

 No.218

File: 1582283674971.jpeg (168.42 KB, 1000x1358, 4798701.jpeg)

>>217
>Why are you testing in production?
Setting up a local copy is such a hassle and Bitdiddle said:

>Don't worry about that. I'm sincerely grateful you found that severe bug, took the time to read the code and offered a way to fix the issue


>We badly need those. Now is the time.


>Thank you again for discovering that awful bug. I believe your stress tests will hit the nginx cache, so they should be safe.

 No.230

File: 1583269287742.png (1.42 MB, 900x1200, 1567550669432.png)

I am trying to change a pretty fundamental type in a functional program, as the current one turned out to be inadequate… Hopefully I won't end up having to rewrite the whole thing. How do functional programmers deal with cases like this? Just get it right before beginning?

 No.232

File: 1583344027901.jpg (38.38 KB, 249x332, capable.jpg)

>>230
Looks like I managed to avoid the situation. Though I am still curious how people deal with situations like that.

 No.257

Currently implementing truth tables for propositional logic in Python. I am aiming to make it general enough so that I can represent every possible table (not just AND, XOR and the usual) with any number of truth-values.

Fun fact: if you have V truth values, then the number of possible truth tables for a binary connective (a truth table with two inputs, basically) is: V ^ (V ^ 2).

This number gets very big very quickly:
V - V ^ (V ^ 2)
1 - 1
2 - 16
3 - 19683
4 - 4294967296 (4.3 billion)
5 - 298023223876953125 (298 quadrillion)

 No.258

>>257
>with any number of truth-values
What are you going to use for not(not(x))?

 No.260

File: 1586901531346.jpg (7.52 KB, 183x275, Curious Miku.jpg)

>>230
What exactly were you trying to do?

 No.261

>>258
Aha. My impression is that NOT(NOT(p)) has the same truth value as p in most many-valued logics, especially those with a finite number of truth values. The Wikipedia article will give some examples:
https://en.wikipedia.org/wiki/Many-valued_logic

The program I'm writing won't be able to handle intuitionistic logic, where NOT(NOT(p)) =/= p, because intuitionistic logic does not use truth tables. At least, it doesn't use finite ones.

 No.262

File: 1586975322394.jpg (733.39 KB, 1000x1300, 7cabe45a4f8164a082f778b9b5….jpg)

>>260
It was an interpreter-like program where certain escape sequences were handled on the parsing side, but I needed to preserve them for later use. I ended up encoding them in the AST using already existing constructs but it's ugly and the proper way would be to change the AST. I know that the whole thing sounds horrible but believe me, it is actually much worse.

 No.286

File: 1589832842137.png (2.01 MB, 620x850, Generaltan.png)

I am giving Coq another go, this time using Programs and Proofs: https://ilyasergey.net/pnp/

I expect to lose track of what is going on somewhere around the middle of the third chapter.

 No.287

>Coq
>Lego
>Isabelle
You forgot to add TypeScript.

 No.291

>>287
What do you mean? If this is a joke, I don't get it.

 No.292

>>291
It is. You'll get it when you're older.

 No.302

File: 1590733791715.jpg (1006.46 KB, 1214x1805, 5389b33aa21c88bc7304f934cc….jpg)

>>286
As expected, it was progressing a bit too fast for me. Before continuing on to chapter 4, I am reading this tutorial: https://mdnahas.github.io/doc/nahas_tutorial

I like that it uses only the most basic parts of Coq and explains them in terms of the Curry-Howard correspondence. It makes me want to write my own proof assistant!

 No.315

File: 1591127549558.jpg (311.75 KB, 2400x3200, 59f557afe19fe20741c3e75c9c….jpg)

Is there a better way to repeatedly destruct a hypothesis so that it can be handled in one go like here?

Goal forall n, n = 0 \/ n = 1 \/ n = 2 \/ n = 3 -> n - 3 = 0.
intros n Cs.
destruct Cs as [C|Cs]; try destruct Cs as [C|Cs]; try destruct Cs as [C|C];
rewrite C;
reflexivity.
Qed.

I guess "repeat" would kind of work, except for the last one where the naming wouldn't match.



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