GNU macro processor - Lexical and syntactic conventions Go to the first , previous , next , last section, table of contents . As m4 reads its input, it separates it into tokens . A token is either a name, a quoted string, or any single character, that is not a part of either a name or a string. Input to m4 can also contain comments.
Names are case-sensitive.
The definitions of letters, digits and other input characters can be changed at any time, using the builtin macro changesyntax . See section Changing the lexical structure of the input , for more information. The value of a string token is the text, with one level of quotes stripped off. See section Changing the quote characters , for more information. The commenting effect of the begin comment character can be inhibited by quoting it.