File: m4.info,  Node: Syntax,  Next: Macros,  Prev: Invoking m4,  Up: Top

3 Lexical and syntactic conventions
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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.  GNU ‘m4’ does not yet understand multibyte locales; all
operations are byte-oriented rather than character-oriented (although if
your locale uses a single byte encoding, such as ISO-8859-1, you will
not notice a difference).  However, ‘m4’ is eight-bit clean, so you can
use non-ASCII characters in quoted strings (*note Changequote::),
comments (*note Changecom::), and macro names (*note Indir::), with the
exception of the NUL character (the zero byte ‘'\0'’).

* Menu:

* Names::                       Macro names
* Quoted strings::              Quoting input to ‘m4’
* Comments::                    Comments in ‘m4’ input
* Other tokens::                Other kinds of input tokens
* Input processing::            How ‘m4’ copies input to output