Openscad coding: holes in a beam

Openscad coding: holes in a beam

(EN)
Division of a beam to position holes
This is a part of Openscad learning.
For a tutorial, see:
https://www.thingiverse.com/thing:7128248
Variables (parameters for the customizer):
L,W, T: length, width, thickness of the beam
HL, HW: length, width of the holes
HF: distance separating holes

Voluntary using excessive number of functions and modules, to gain in clarity.
Voluntary NOT using parameters in functions and modules, loosing flexibility (I could write a version with parameters later)
It is up to you to define your best way of coding!
Note: small values like 0.1 are sometimes added or subtracted. This is a technical way to make better pictures in the view.

(FR)
Division d'une poutre pour positionner des trous.
Ceci fait partie d'un apprentissage d'Openscad.
Voir le tutoriel:
https://www.thingiverse.com/thing:7128248
Les variables (qui sont des paramètres pour le customizer):
L,W, T: longueur, largeur et épaisseur de la poutre
HL, HW: