my LaTeX custom macros file as of 29.09.2016

perun.sty

\ProvidesPackage{perun}[2016/09/23 v0.1 My own macros]
% http://tex.stackexchange.com/questions/11890/where-to-put-a-custom-macros-file

\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage[gen]{eurosym}
\usepackage{enumitem}
\usepackage{siunitx}
\usepackage{mathtools} % provides dcases* environment in math mode
\usepackage[normalem]{ulem}

\sisetup {
    group-minimum-digits = 4,
    output-decimal-marker = {,}
}

\ProcessOptions\relax

%%% MATHEMATICS: SYMBOLS %%%
\newcommand{\ra}{\rightarrow}
\newcommand{\la}{\leftarrow}
\newcommand{\lra}{\leftrightarrow}
\newcommand{\Ra}{\Rightarrow}
\newcommand{\La}{\Leftarrow}
\newcommand{\Lra}{\Leftrightarrow}
\newcommand{\meet}{\wedge}
\newcommand{\join}{\vee}

%%% MATHEMATICS: LETTERS %%%
\newcommand{\N}{\mathbb{N}}
\newcommand{\R}{\mathbb{R}}
\newcommand{\Q}{\mathbb{Q}}
\newcommand{\Z}{\mathbb{Z}}

\newcommand{\calM}{\mathcal{M}}

%%% MATHEMATICS: NAMES %%%
\newcommand{\Luka}{}
\def\Luka/{Łukasiewicz}

%%% CURRENCY & MONEY %%%
\newcommand{\meuro}{\text{\euro}} % http://tex.stackexchange.com/a/110990/113599

\endinput