It took me some time to understand that sugar syntax.
First of : it's & :to_s obviously.
Operator is &.

What does it do ?

it turns

mythings.map(& :upcase)
# is the same as 
mythings.map(&:upcase)

into

mythings.map { |mything| mything.upcase }

Remark : sugar syntax can be a pain in the butt. I hope you do see it.

The map method applies the "block" { |mything| mything.upcase } on each and every elements of mythings and returns an enumerable of class mythings.class containing each result.

The operator is & and the argument in my example is :upcase. :upcase is a Symbol.
Symbols have a smart to_proc method.

Another example :

require 'date'
[1,DateTime.now,3].map(&:to_s)
# => ["1", "2021-09-05T12:06:54+02:00", "3"]

So how does it work ?

• &̀ when a parameter of a method is prepended with & then ruby knows this parameter to be a Proc

• :upcase is a symbol.

So the &:myproc is a smart shortcut implemented to turn the symbol :myproc into a proc.

Let's try it :

def call_my_block ( my_parameter, &myblock)
  myblock.call.myblock
end

The parameter &myblock is known to be a block.

When I use method call_my_block with the argument &:my_symbol :

• The second parameter is known to be a block.
• The argument will be translated into :my_symbol.to_proc
  If the first argument is of class KlassandKlassactually has a my_symbol method, then it will call it.

Example :

call_my_block DateTime.now , &:to_s translates into :

:to_s.to_proc.call DateTime.now 

note that :

a = :to_s.to_proc
#=> #<Proc:0x000055e77c191c98(&:to_s)>
a.call(13)
#=> "13"
a.class
#=> Proc

Hence :

call_my_block DateTime.now , &:to_s
# => "2021-09-05T12:06:00+02:00" 
[1,DateTime.now,3].map { |val| call_my_block(val,&:to_s) }
#=> ["1", "2021-09-05T12:21:54+02:00", "3"]
[1,DateTime.now,3].map(&:to_s)
["1", "2021-09-05T12:23:22+02:00", "3"]

Note ::

• A function/methods has parameters.
• When called the function is given arguments

In other terms, an argument is the value of a parameter.

Impressive monitoring tool.
Raise alerts with complete configuration file to get informed through mail / etc

When they say "about no configuration", it is true.
It's a "tool" you take and use.

Just amazingly simple and pure efficiency.

Bravo.

Note : it will not help you understand what happened two weeks ago. It's not here to help you who did what three years ago, or what has happened last month with this or that. It 's a tool to monitor a platform health.

search engine for cc images.

A must have seen about database indexing.

I just like this video so much.
What a great show and explain demonstration.

L'accessibilité numérique au service de l'inclusion des personnes handicapées. Propose de faire des audits / diagnostic / formation / conseil etc.

building fully self-contained Python zipapps as outlined in PEP 441 but with all their dependencies included!

Shiv’s primary goal is making distributing Python applications fast & easy.

How it works
Shiv includes two major components: a builder and a small bootstrap runtime.

A must have : explains what the regexp is doing
A great tool to learn / design regexp.

Changes my everyday life.

Useful guide.
Marked for soon usage.

kubectl logs -f api-xxxxxxxx | lnav

Excellent log parser, featureful, very readable, very intuitive with great filter features...
A must have.

One can even do some requests on a log :

SELECT c_ip, count(*), sum(sc_bytes) AS total FROM access_log
               GROUP BY c_ip ORDER BY total DESC;

Although I did not try this feature yet

Very interesting application (probably one I really care having).
Particularly interesting to learn / try experiments with kids.

I'm going to try and use it with my kids.