@code
{sample-code}
Use the @code
command to indicate text that is a piece of a
program and which consists of entire syntactic tokens. Enclose the
text in braces.
Thus, you should use @code
for an expression in a program, for
the name of a variable or function used in a program, or for a
keyword. Also, you should use @code
for the name of a
program, such as diff
, that is a name used in the machine. (You
should write the name of a program in the ordinary text font if you
regard it as a new English word, such as `Emacs' or `Bison'.)
Use @code
for environment variables such as TEXINPUTS
,
and other variables.
Use @code
for command names in command languages that
resemble programming languages, such as Texinfo or the shell.
For example, @code
and @samp
are produced by writing
`@code{@@code}' and `@code{@@samp}' in the Texinfo
source, respectively.
Note, however, that you should not use @code
for shell options
such as `-c' when such options stand alone. (Use @samp
.)
Also, an entire shell command often looks better if written using
@samp
rather than @code
. In this case, the rule is to
choose the more pleasing format.
It is incorrect to alter the case of a word inside an @code
command when it appears at the beginning of a sentence. Most computer
languages are case sensitive. In C, for example, Printf
is
different from the identifier printf
, and most likely is a
misspelling of it. Even in languages which are not case sensitive, it
is confusing to a human reader to see identifiers spelled in different
ways. Pick one spelling and always use that. If you do not want to
start a sentence with a command written all in lower case, you should
rearrange the sentence.
Do not use the @code
command for a string of characters shorter
than a syntactic token. If you are writing about `TEXINPU', which
is just a part of the name for the TEXINPUTS
environment
variable, you should use @samp
.
In particular, you should not use the @code
command when writing
about the characters used in a token; do not, for example, use
@code
when you are explaining what letters or printable symbols
can be used in the names of functions. (Use @samp
.) Also, you
should not use @code
to mark text that is considered input to
programs unless the input is written in a language that is like a
programming language. For example, you should not use @code
for
the keystroke commands of GNU Emacs (use @kbd
instead) although
you may use @code
for the names of the Emacs Lisp functions that
the keystroke commands invoke.
In the printed manual, @code
causes TeX to typeset the
argument in a typewriter face. In the Info file, it causes the Info
formatting commands to use single quotation marks around the text.
For example,
Use @code{diff} to compare two files.
produces this in the printed manual:
Use
diff
to compare two files.
and this in the Info file:
Use `diff' to compare two files.
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