3.1 Macro names =============== A name is any sequence of letters, digits, and the character `_' (underscore), where the first character is not a digit. `m4' will use the longest such sequence found in the input. If a name has a macro definition, it will be subject to macro expansion (Note: Macros). Names are case-sensitive. Examples of legal names are: `foo', `_tmp', and `name01'.