The following conventions are used for names of macros, strings,
and registers. External names available to documents that use
the groff ms macros contain only uppercase letters and digits.
Internally the macros are divided into modules; naming
conventions are as follows:
• Names used only within one module are of the form module*name.
• Names used outside the module in which they are defined are of
the form module@name.
• Names associated with a particular environment are of the form
environment:name; these are used only within the par module.
• name does not have a module prefix.
• Constructed names used to implement arrays are of the form
array!index.
Thus the groff ms macros reserve the following names:
• Names containing the characters *, @, and :.
• Names containing only uppercase letters and digits.
