# Programming Languages I Know and Cherish

# Turing complete:

## Turing machines

Representative project: [A Turing Machine that finds out the nth prime](https://github.com/NunoSempere/Turing_Machine)

Useful for: Elegant & nifty arguments in set theory. The programming language for the mathematician.

Personal experience: Cognitively effortful, interesting to work with. I've programmed a TM that finds the n-th prime.

## C and C++

Representative project: [Calibration](https://github.com/NunoSempere/calibration)

Useful for: Pedal to the metal programming.

Personal experience: One of the first programming languages I learnt, and thus my documentation was in Spanish. I've used it to crunch numbers when a speedup mattered. I've also used it in ways it wasn't meant to: to program a database application, to analyze a lexical corpus, to solve riddles. This has led me to appreciate higher languages more, and to understand them better. For example:

In JavaScript, consider the function:

```
function reverseArrayInPlace(array) {
  for (let i = 0; i < Math.floor(array.length / 2); i++) {
    let old = array[i];
    array[i] = array[array.length - 1 - i];
    array[array.length - 1 - i] = old;
  }
  return array;  
}
```

This function reverses an array, and changes it. However, the scope of the array which the function manipulates is local, and yet the original array is changed. This is because, although JavaScript doesn't work with pointers, it is working with pointers, and the local copy of the pointer is pointing to the same place.

Having had to deal with memory allocation, working in a language which just deals with it is orgasmic.

## Python.

Representative project: Classifying images in machine learning (no link)

Useful for: Mostly everything.

Personal experience: I learnt Python while young, and used it to program Arduino. However, I hadn't used it much, until recently for machine learning. I have no complaints, but I'm also a little rusty.

## R

Representative project: [EA Mental Health](https://forum.effectivealtruism.org/posts/FheKNFgPqEsN8Nxuv/ea-mental-health-survey-results-and-analysis)

Useful for: Statistical analysis; writting programs quickly. Beautiful plots.

Personal experience: I view this language with a lot of affection, and I like it a lot; I have found analyzing datasets to be very cognitively stimulating. The ggplot2 library is amazing. The time required to create a new program is basically 0, in RStudio, because you don't really compile the whole program at once, but instruction by instruction / line by line. Would recommend. Ultimately, when working with huge datasets, what one does is to load a library which has functions written in C.

## Haskell
Representative project: [Newspaper scrapper](https://github.com/NunoSempere/NewspaperScraper)

Useful for: Aesthetics.

Personal experience: Learnt for the novelty, and I appreciate the aesthetic appeal. Otherwise, not much to say.

## PHP 

Representative project: [shapleyvalue.com](http://shapleyvalue.com)

Useful for: Server side programming.

Personal experience: I learnt PHP to program the above webpage. Ultimately, however, I could have just used JavaScript, because I don't really needed a database / everything could have been computed on the user's side. Demistifyies some webpages. 

## JavaScript
Representative project: None, currently learning (Oct 2019).

Useful for: Code which is executed on the client's side. Interactive webpages. Server side with Node.js

Personal experience: Limited, currently learning.

## Others.
Unix shell, Matlab. Honorable mention to JSFuck for its practical uses. Honorable mention to Intercal for the following paragraph, which has stayed with me: 

> Until the new INTERCAL compiler with better RYM[6] access comes out, the old compiler has no way of knowing which language you are familiar with and thus it doesn't know what language to produce its output in[7]. INTERCAL elegantly solves this problem by producing its output in Roman numerals, under the assumption that when Rome was at the height of its strength, half the world was under its dominion, so the comprehension of Roman numerals is part of our racial memory.
> [Source](http://www.catb.org/~esr/intercal/paper.html)


# Not Turing complete

## Latex
Representative project: My CV.

Useful for: Typesetting; producing beautiful pdfs.

Personal experience: There when I've needed it. 

## Markdown
Representative project: This document is written in markdown.

Useful for: GithubPages. Just writting without the need to worry about html.

Personal experience: Easy to pick up. Pity that it doesn't really support math.

## HTML and CSS
Representative project: [easyfirma.es](easyfirma.es)

Useful for: Webpages!

Personal experience: Templates are not evil; they're the difference between [shapleyvalue.com](shapleyvalue.com) and [easyfirma.es](easyfirma.es). Easy to pick up. Also easy to clutter.

##  MySQL / MariaDB
Representative project: None as of yet. 

Useful for: Databases on the server's side.

Personal experience: Pretty straightforward; it's not even Turing complete. I prefer MariaDB on principle, because it's Free (Libre!) Software.