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 (⇒Macros). Names are case-sensitive. Examples of legal names are: 'foo', '_tmp', and 'name01'.