| | | What good are macros? |
What is the value in defining personal LaTeX macros?
Suppose that you are writing a document in which you are going to
refer to Texas A&M University twenty-five times. To save typing,
you might type "Texas A&M University" once and then copy it
twenty-four times with the mouse.
Unfortunately, you find out when you run the document through
LaTeX that LaTeX wanted you to type "A\&M"
instead of "A&M". Or perhaps you decide later that
you want to say "Texas A&M University System" instead of "Texas A&M University."
By defining a LaTeX macro, you can simultaneously save typing and protect yourself in the event of future revisions. If you type
\newcommand{\tamu}{Texas A\&M University}
Bonfire is a tradition at \tamu.
LaTeX will translate this into
Or you can type
\tamu{} is a land-grant institution.
The point of the empty braces in the preceding example is that
LaTeX interprets white space immediately following a control
sequence as a delimiter terminating the name of the control
sequence. You have to fool LaTeX if you really want a space
to appear in the output. There is a standard LaTeX package
named xspace that handles this annoying
feature automatically. If you have a current LaTeX
installation that includes the
tools bundle,
then you can put \usepackage{xspace} in the preamble of
your source document, change the macro definition to
\newcommand{\tamu}{Texas A\&M University\xspace}
and you should not have to worry about putting empty braces at the end of the control sequence in text.
By using the \tamu macro, you save typing, and you also
make it easy to revise your document. If you decide to change
"Texas A&M University"
to "Texas A&M University System",
you need only make this change once, in the
definition of the macro \tamu.
(Aside to former plain TeX users: LaTeX's
\newcommand command is preferable to TeX's \def
command, because \newcommand prevents you from
accidentally redefining an existing macro. If you really do want
to redefine an existing LaTeX command, and you are sure that
no disaster will ensue, then you can use
LaTeX's \renewcommand command.)
The Math 696 course
pages were last modified April 5, 2005. | | | What good are macros? |