Beg for square brackets!

Question

If you like snakes, beg for square brackets.

If you are a black key, beg from "in".

If you are another black key, beg for curly brackets.

If you are fully functional, beg square brackets in a bar.

If you like coffee, beg parentheses with two dots. Don't forget the filter.

If you have trouble in speaking, beg parentheses in a loop.

If you like jewels, beg parentheses with two dots. Also curly brackets if needed.

If you don't have a direction, beg for parentheses.

What are you actually begging for?

Subtle Hint:

The bold texts are keywords.

Answer 1

Alright, second try:

A loop

Clues I've gotten so far:

"If you like snakes" is Python, where [] is used to create a list that can be looped through.
"If you are fully functional" is Haskell, where [ (operation) | (pattern) <- list] loops through a list and performs an operation on matches
"If you like coffee" is Java, where you use for (starting variable; filter; operation) to create a loop
"If you have trouble speaking" is Stutter, which has no special characters, thus you would just declare loop
And "If you like jewels" is Ruby, where ({:}) can be used to generate an array that you can loop through

Answer 2

Is it iteration?

Clues:

All of these are different programming languages.
Snakes: python
Black keys: F# and C# (keys on a piano)
Fully Functional: Haskell
Coffee: Java
Trouble speaking: Lisp
Jewels: Ruby
Don't have direction: Maybe Scala? As a play on Scalar (as opposed to a vector, which has direction)