This Week I Learned: 2022W44

Cat

I had always used cat to print the content of a file. I just learned that cat is for conCATenate. It allows to print the content of multiple files and to possibly pipe it to another file / process.

cat file1 file2 file3

will print the content of each file in order, concatenated.

PHP

PHP has endif, endwhile, endfor, endforeach and endswitch statements.

Can be useful if you are mixing PHP and HTML (which you absolutely shouldn’t of course):

<?php if ($a == 5): ?>
A is equal to 5
<?php endif; ?>

And with if:

<?php
if ($a == 5):
    echo "a equals 5";
    echo "...";
elseif ($a == 6):
    echo "a equals 6";
    echo "!!!";
else:
    echo "a is neither 5 nor 6";
endif;
?>

Reminds a bit of ruby with its if ... end. Funny.

Examples taken from official documentation. I worked with PHP for years and had never encountered this syntax. I’s probably a good sign ;).

Git

This git plugin (git-redate) allows to easily change the datetime of some past commits.

Vim - Neovim - Lua

You can have a lua folder in your ~/.config/nvim folder which will make these scripts discoverable.

Then you can have multiple levels of files:

├── init.vim
├── lua
│   ├── einenlum
│   │   ├── init.lua

Everything in lua/einenlum/init.lua will automatically be loaded when requiring einenlum in my init.vim file (VimL script):

lua require('einenlum')

This is kind of equivalent to what Python has with packages and __init__.py files.

You can check a bit more how it works in my dotfiles.

Vim - Neovim

I have used vim for many years now but I didn’t know _ (underscore) leads to the “real” beginning of the line (compared to 0).

Laravel - Mocking time in tests

In Laravel, if you want to change the current time, you can use $this->travelTo. It accepts Carbon and DateTimeInterface objects, closures are strings.

$this->travelTo('2022-11-06');
$this->travelTo(\DateTimeImmutable::createFromFormat('Y-m-d', '2022-11-06'));

Laravel - Blade - Components

Blade, Laravel’s templating engine, allows to natively create components. Every template in resources/views/components (ex: my-card.blade.php) can then be called in another template (ex: <x-my-card></x-mx-card>).

You can pass children components that will be accessible through {{ $slots }} (equivalent to React’s { children }).

Twig also has components.