mypackage.sty

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{mypackage}[2023/06/26 My package]

%------------------------------------------------------------------------------
% Load packages.
%------------------------------------------------------------------------------

% This includes package `amsfonts'.
% This package MUST be loaded BEFORE the package `mathtools'.
\RequirePackage{amssymb}

% This package includes the package `amsmath' and fixes bugs for `amsmath'.
\RequirePackage{mathtools}

% This package MUST be loaded AFTER the packages `amsmath' and `mathtools'.
\RequirePackage{amsthm}

% This package provides LaTex 3 command customization utilities.
\RequirePackage{xparse}

% This package parses lists inside the command `\newcommand'.
\RequirePackage{listofitems}

% This package provide a nice looking if-then-else structure and comparison functionalities.
\RequirePackage{ifthen}

%------------------------------------------------------------------------------
% Define operators and symbols.
%------------------------------------------------------------------------------

% Absolute value.
\DeclarePairedDelimiter{\absTmp}{\lvert}{\rvert}
\NewDocumentCommand{\abs}{m}{\absTmp*{#1}}
% Ceiling.
\DeclarePairedDelimiter{\ceilTmp}{\lceil}{\rceil}
\NewDocumentCommand{\ceil}{m}{\ceilTmp*{#1}}
% Floor.
\DeclarePairedDelimiter{\floorTmp}{\lfloor}{\rfloor}
\NewDocumentCommand{\floor}{m}{\floorTmp*{#1}}
% Evaluate.
\DeclarePairedDelimiter{\evalTmp}{.}{\rvert}
\NewDocumentCommand{\eval}{m}{\evalTmp*{#1}}
% Parenthese.
\DeclarePairedDelimiter{\paTmp}{\lparen}{\rparen}
\NewDocumentCommand{\pa}{m}{\paTmp*{#1}}
% Bracket.
\DeclarePairedDelimiter{\brTmp}{\lbrack}{\rbrack}
\NewDocumentCommand{\br}{m}{\brTmp*{#1}}
% Brace.
\DeclarePairedDelimiter{\BTmp}{\lbrace}{\rbrace}
\NewDocumentCommand{\B}{m}{\BTmp*{#1}}
% Set.
\NewDocumentCommand{\set}{m}{\B{#1}}
% Norm.
\DeclarePairedDelimiter\norm{\lVert}{\rVert}
% Inner product.
\DeclarePairedDelimiter\inner{\langle}{\rangle}
% -th in superscript.
\NewDocumentCommand{\opTh}{}{\operatorname{th}}

% Define common symbols.
% See `amsmath' section 9.2 for details.

% Fields.
\NewDocumentCommand{\field}{m}{\mathbf{#1}}
% General field.
\NewDocumentCommand{\F}{}{\field{F}}
% Complex number.
\NewDocumentCommand{\C}{}{\mathbb{C}}
% Natural number.
\NewDocumentCommand{\N}{}{\mathbb{N}}
% Rational number.
\NewDocumentCommand{\Q}{}{\mathbb{Q}}
% Real number.
\NewDocumentCommand{\R}{}{\mathbb{R}}
% Integer number.
\NewDocumentCommand{\Z}{}{\mathbb{Z}}

% Plus plus operation.
% Braces are used to make operators style as symbols, in particular no spaces are added before and after.
\NewDocumentCommand{\pp}{}{{+}\!{+}}
% Minus minus operation.
% Braces are used to make operators style as symbols, in particular no spaces are added before and after.
\NewDocumentCommand{\mm}{}{{-}\!{-}}
% LIM operator.
\DeclareMathOperator*{\LIM}{LIM}

% Proof environments reference text.
\NewDocumentCommand{\pf}{m}{%
  Proof of \cref{#1}%
}

% Proof statements reference text.
\NewDocumentCommand{\byOptionalArgumentProcess}{m}{(#1)}
\NewDocumentCommand{\by}{m >{\SplitList{,}} o}{%
  \IfNoValueTF{#2}{%
    \text{(by \cref{#1})}%
  }{%
    \text{(by \cref{#1}\ProcessList{#2}{\byOptionalArgumentProcess})}%
  }%
}

% Proof statements reference the induction hypothesis.
\NewDocumentCommand{\byIH}{}{\text{(by the induction hypothesis)}}