LaTeX: Much ado about the old font commands

bxoldfontcmd.sty

% bxoldfontcmd.sty
%% package declaration
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{bxoldfontcmd}
\def\bxof@pkgname{bxoldfontcmd}

%% code guards
\@onlypreamble\bxof@restore@codes
\edef\bxof@restore@codes{%
  \catcode33=\the\catcode33%
  \catcode39=\the\catcode39%
  \catcode45=\the\catcode45%
  \catcode46=\the\catcode46%
  \catcode47=\the\catcode47%
  \catcode58=\the\catcode58%
  \catcode59=\the\catcode59%
  \catcode60=\the\catcode60%
  \catcode62=\the\catcode62%
  \catcode94=\the\catcode94%
  \endlinechar=\the\endlinechar%
\relax}
\catcode33=12 % <!>
\catcode39=12 % <'>
\catcode45=12 % <->
\catcode46=12 % <.>
\catcode47=12 % </>
\catcode58=12 % <:>
\catcode59=12 % <;>
\catcode60=12 % <<>
\catcode62=12 % <>>
\catcode94=7 % <^>
\endlinechar=13 %
\AtEndOfPackage{\bxof@restore@codes}
\providecommand\bxDebug[1]{}

%--------------------------------------- helpers

%% packages
\RequirePackage{keyval}

%% unique tokens
\def\bxof@end{\bxof@end@}

%% switches
\newif\ifbxof@ok

%% \bxof@set@number\CS{<number>}
\def\bxof@set@number#1#2{%
  #1=#2\relax}

%--------------------------------------- options

%% \ifbxof@aho
\newif\ifbxof@aho
%% \ifbxof@total
\newif\ifbxof@total
%% \ifbxof@stats
\newif\ifbxof@stats
%% \bxof@mode
\chardef\bxof@mode@banned=0
\chardef\bxof@mode@deprecated=1
\chardef\bxof@mode@allowed=2
\chardef\bxof@mode@praised=3
\let\bxof@mode\bxof@mode@deprecated
%% \bxof@freq
\newcount\bxof@freq \bxof@freq=1000000

%% 'noaho'/'aho'
\DeclareOption{noaho}{%
  \bxof@ahofalse}
\DeclareOption{aho}{%
  \bxof@ahotrue}

%% 'nostats'/'stats'
\DeclareOption{nostats}{%
  \bxof@statstfalse}
\DeclareOption{stats}{%
  \bxof@statstrue}

%% 'deprecated' etc.
\DeclareOption{banned}{%
  \let\bxof@mode\bxof@mode@banned}
\DeclareOption{deprecated}{%
  \let\bxof@mode\bxof@mode@deprecated}
\DeclareOption{praised}{%
  \let\bxof@mode\bxof@mode@praised}
\DeclareOption{allowed}{%
  \let\bxof@mode\bxof@mode@allowed}

%% keyval options
\DeclareOption*{%
  \edef\bxof@tmpa{\noexpand\setkeys{bxof}{\CurrentOption}%
  }\bxof@tmpa}
\define@key{bxof}{freq}{%
  \bxof@set@number\bxof@freq{#1}}

%% process
\ProcessOptions\relax
%% postprocess
\ifnum\bxof@freq<\@ne
  \PackageError\bxof@pkgname
   {The 'freq' value must be positive\MessageBreak
    (value=\the\bxof@freq)}
   {That value is changed to 1.\MessageBreak\@ehc}
  \bxof@freq=1
\fi
\ifnum\bxof@mode=\bxof@mode@banned
  \bxof@freq=1
\fi

%--------------------------------------- 

%% variables
\let\bxof@name\relax
\let\bxof@cseq\relax
%\bxof@g@C/<name>
\def\bxof@g@total{0}

%% \bxof@g@name@list
\let\bxof@g@name@list\@empty

%% \bxof@get@name\CS
\def\bxof@get@name#1{%
  \begingroup\escapechar\m@ne
    \xdef\bxof@g@tmpa{\def\noexpand\bxof@name{\string#1}}%
  \endgroup \bxof@g@tmpa
  \edef\bxof@cseq{\@backslashchar\bxof@name}}

%% \bxof@cmd@declared\FCS
\@onlypreamble\bxof@cmd@declared
\def\bxof@cmd@declared#1{%
  \begingroup
  \bxof@get@name#1%
  \bxDebug{DECLARED: \bxof@name}%
  \expandafter\bxof@cmd@declared@a\csname bxof@g@C/\bxof@name\endcsname
  \endgroup}
\@onlypreamble\bxof@cmd@declared@a
\def\bxof@cmd@declared@a#1{%
  \ifx#1\relax
    \let\do\relax
    \xdef\bxof@g@name@list{\bxof@g@name@list\noexpand\do{\bxof@name}}%
    \gdef#1{0}%
  \fi}

%% \bxof@cmd@used\FCS
\def\bxof@cmd@used#1{%
  \begingroup
  \bxof@get@name#1%
  \bxof@countup
  \ifbxof@ok
    \ifnum\bxof@mode=\bxof@mode@banned
      \bxof@issue@error
    \else\ifnum\bxof@mode=\bxof@mode@deprecated
      \bxof@issue@warning
    \else\ifnum\bxof@mode=\bxof@mode@praised
      \bxof@issue@praise
    \fi\fi\fi
  \fi
  \endgroup}

%% \bxof@countup
\def\bxof@countup{%
  \expandafter\bxof@countup@a\csname bxof@g@C/\bxof@name\endcsname}
\def\bxof@countup@a#1{%
  % check the phase
  \bxof@okfalse
  \@tempcnta=\ifbxof@total\bxof@g@total\else#1\fi\relax
  \@tempcntb\@tempcnta \divide\@tempcntb\bxof@freq
  \multiply\@tempcntb-\bxof@freq \advance\@tempcntb\@tempcnta
  \ifnum\@tempcntb=\z@ \bxof@oktrue \fi
  % command count
  \@tempcnta=#1\relax \advance\@tempcnta\@ne
  \xdef#1{\the\@tempcnta}%
  % total count
  \@tempcnta=\bxof@g@total\relax \advance\@tempcnta\@ne
  \xdef\bxof@g@total{\the\@tempcnta}%
  \bxDebug{\bxof@name=#1; total=\bxof@g@total}}

%% end-document hook
\AtEndDocument{%
  \ifnum\bxof@mode=\bxof@mode@deprecated
    \bxof@issue@warning@last
  \fi
  \ifbxof@stats
    \bxof@show@stats
  \fi}

%--------------------------------------- aho font

%% if that one really exists....
\IfFileExists{bxahofont.sty}{%
  \RequirePackage{bxahofont}[]%
}{}

\ifx\textaho\@undefined
%% declare the aho font in private
\def\bxof@aho@fam{bxof-aho}\let\bxof@tmpa\bxof@aho@fam
\DeclareFontFamily{OT1}{\bxof@tmpa}{}
\DeclareFontShape{OT1}{\bxof@tmpa}{m}{n}{<->cmfi10}{}
\def\do#1#2{%
  \DeclareFontShape{OT1}{\bxof@tmpa}{#1}{#2}{<->ssub*\bxof@tmpa/m/n}{}}
\do{m}{it}\do{m}{sl}\do{m}{sc}
\do{bx}{n}\do{bx}{it}\do{bx}{sl}\do{bx}{sc}
\DeclareRobustCommand\ahofont{%
  \not@math@alphabet\ahofont\mathaho
  \usefont{OT1}{\bxof@aho@fam}{m}{it}}
\DeclareTextFontCommand{\textaho}{\ahofont}
\DeclareMathAlphabet{\mathaho}{OT1}{\bxof@aho@fam}{m}{it}
%%
\fi

%--------------------------------------- messages

%% \bxof@issue@error
\def\bxof@issue@error{%
  \PackageError\bxof@pkgname
   {The old font comamnd '\bxof@cseq' is banned}
   {Don't even think of writing the command!\MessageBreak
    And throw away all the obsolete stuffs that depend on it!}}

%% \bxof@issue@warning
\def\bxof@issue@warning{%
  \PackageWarning\bxof@pkgname
   {Alas, the old font comamnd '\bxof@cseq' is used\MessageBreak
    on input line \the\inputlineno.\MessageBreak
    (The later occurrence of similar warnings may\MessageBreak
    be suppressed.)\@gobbletwo}}

%% \bxof@issue@warning@last
\def\bxof@issue@warning@last{%
  \ifnum\bxof@g@total>\z@
    \let\bxof@tmpa\@empty
    \def\do##1{%
      \expandafter\ifnum\csname bxof@g@C/##1\endcsname>\z@
        \edef\bxof@tmpa{\bxof@tmpa\space\@backslashchar##1}\fi}%
    \bxof@g@name@list
    \PackageWarningNoLine\bxof@pkgname
     {Some of the old font comamnds were used:\MessageBreak
      \space\bxof@tmpa\MessageBreak
      All those commands are deprecated, because you\MessageBreak
      have declared so. If that is not what you want,\MessageBreak
      try \string\usepackage[allowed]{\bxof@pkgname}}
  \fi}

%% \bxof@show@stats
\begingroup
\catcode10=12
\gdef\bxof@show@stats{%
  \let\bxof@tmpa\@empty
  \def\do##1{%
    \expandafter\ifnum\csname bxof@g@C/##1\endcsname>\z@
      \edef\bxof@tmpa{\bxof@tmpa\space\@backslashchar##1: %
        \csname bxof@g@C/##1\endcsname^^J}%
    \fi}%
  \bxof@g@name@list
  \typeout
   {Here is how many times old font commands are invoked:^^J%
    \bxof@tmpa\space Total: \bxof@g@total}%
  }
\endgroup

%--------------------------------------- the big praise

%% \bxof@praise@message
\begingroup
\catcode`\^^A=14 \catcode`\#=12
\catcode`\^^\=0 \catcode`\^^[=1 \catcode`\^^]=2 \catcode`\^^X=6
\endlinechar=10 \catcode10=12 \catcode96=7 \let\do\@makeother
\dospecials``\gdef``\bxof@praise@message``X1``X2``[``A
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
! ! ! ! ! ! ! ! ! !   E X C E L L E N T   ! ! ! ! ! ! ! ! ! !
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
       ____
    ___HHHH   _____   You are using the command ``X1
   / .   . \ |NICE!|                on input line ``X2.
   \  ---  / |~~~~~
 V :#######: Y        I'll greatly praise you for your use
  \/   o   \/                     of such old font commands.
  {    o    }
   \_______/                                         HURRAY!!
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%``]``A
``\endgroup%

%% \bxof@issue@praise
\begingroup
\catcode10=12
\gdef\bxof@issue@praise{%
  \typeout{^^J%
    \bxof@praise@message{\bxof@cseq}{\the\inputlineno}}}
\endgroup

%--------------------------------------- define the comamnds

%% \DeclareOldFontCommand redefined
\def\DeclareOldFontCommand#1#2#3{%
  \bxof@cmd@declared#1%
  \let#1\@undefined
  \ifbxof@aho
    \DeclareRobustCommand#1{%
      \bxof@cmd@used#1%
      \@fontswitch{\ahofont}{\mathaho}}
  \else
    \DeclareRobustCommand#1{%
      \bxof@cmd@used#1%
      \@fontswitch{#2}{#3}}
  \fi}

%% redefine the commands
\DeclareOldFontCommand{\rm}{\normalfont\rmfamily}{\mathrm}
\DeclareOldFontCommand{\sf}{\normalfont\sffamily}{\mathsf}
\DeclareOldFontCommand{\tt}{\normalfont\ttfamily}{\mathtt}
\DeclareOldFontCommand{\bf}{\normalfont\bfseries}{\mathbf}
\DeclareOldFontCommand{\it}{\normalfont\itshape}{\mathit}
\DeclareOldFontCommand{\sl}{\normalfont\slshape}{\@nomath\sl}
\DeclareOldFontCommand{\sc}{\normalfont\scshape}{\@nomath\sc}
% pTeX commands
\ifx\mcfamily\@undefined\else
\DeclareOldFontCommand{\mc}{\normalfont\mcfamily}{\mathmc}
\fi
\ifx\gtfamily\@undefined\else
\DeclareOldFontCommand{\gt}{\normalfont\gtfamily}{\mathgt}
\fi

%--------------------------------------- all done
\endinput
%% EOF

sample.tex

\documentclass[a4paper]{article}
\usepackage{bxoldfontcmd}% '\bf' is deprecated
%\usepackage[freq=5]{bxoldfontcmd}% more warnings
%\usepackage[stats]{bxoldfontcmd}% show statistics
%\usepackage[banned]{bxoldfontcmd}% '\bf' is banned
%\usepackage[praised]{bxoldfontcmd}% '\bf' is praised! hurray!
\begin{document}
Once upon a time, there {\it were} some {\bf old} font commands.
\end{document}

Usage

You can laod the package as follows:

\usepackage[<option>,...]{bxoldfontcmd}

The available options are:

• banned/deprecated/allowed/praised: Specifies how the use of old font commands is treated.
• stats: Shows the usage statistics of old commands at the end of the process.
• nostats: Negation of stats.
• freq=<number>: Frequency that specifies how often the (error/warning/praise) message is shown on the terminal.
• aho: Tells that the old font comamnd should ignore its definition and always change to the 'CM Funny Italic' font.
• noaho: Negation of aho.