Guide to LaTeX (4th Edition) (Tools and Techniques

190 Chapter 8. User Customizations
First, a new length parameter \wdth is created, then \defbox is defined
so that \wdth is set equal to the length of its argument (Section 8.2), and
finally \textbox makes a framed box of that same width containing its
argument, centered. (Do not name the length parameter \width, for this
already exists, Section 4.7.5.)
as wide as this text\\
\defbox{as wide as this text}\textbox{}\\
\textbox{text}\\
\textbox{longer text}
as wide as this text
text
longer text
Example 3: A footnote command \myftnote is to be created that behaves
as the normal command \footnote{text} in putting text into a footnote,
but instead of using numbers as the marker, it should take the symbols
∗ † ‡ § ∗∗ †† ‡‡ one after the other, starting again with the symbol ∗
on each new page. First a new counter must be established that will be
reset to zero every time the page counter is incremented. This is done
with (see Section 8.1.2)
\newcounter{myfn}[page]
making a user-defined counter myfn that is set to zero every time the
page counter is incremented. ∗ Next the command
\renewcommand{\thefootnote}{\fnsymbol{footnote}}
redefines the footnote marker to be that symbol in the sequence given
by the counter footnote (Sections 4.10.2 and 8.1.4). Now the actual new
footnote command can be constructed with
\newcommand{\myftnote}[1]{\setcounter{footnote}{\value{myfn}}%
\footnote{#1}\stepcounter{myfn}}
yielding the desired results. The user-defined command \myftnote possesses
one argument, which is passed to the L AT E X \footnote command
after the L AT E X counter footnote has been set equal to the value of the
user counter myfn. Once the command \footnote has been executed,
the counter myfn is then incremented by one with \stepcounter{myfn}.
This counter, however, is reset to zero whenever the page counter is
incremented, that is, whenever a new page begins.
The footnote on the previous page was generated with the command
\myftnote as described. It is now used here † and again here ‡ , demonstrating
how the symbols have been reset on a new page.
Example 4: A command \alpheqn is to be set up so that once it has been
called, the subsequent equations will all have the same number but be
∗ Actually the page counter is not incremented exactly at the end of the page; LAT E X reads
in the whole paragraph before it decides if and where a page break should occur. This can
cause problems with resetting the myfn counter near the top of a page.
† another footnote
‡ and yet another footnote