Non-Emacs Syntax Tables
-----------------------

  A "syntax table" is an array indexed by the characters in your
character set.  In the ASCII encoding, therefore, a syntax table has
256 elements.  Regex always uses a `char *' variable `re_syntax_table'
as its syntax table.  In some cases, it initializes this variable and
in others it expects you to initialize it.

   * If Regex is compiled with the preprocessor symbols `emacs' and
     `SYNTAX_TABLE' both undefined, then Regex allocates
     `re_syntax_table' and initializes an element I either to `Sword'
     (which it defines) if I is a letter, number, or `_', or to zero if
     it's not.

   * If Regex is compiled with `emacs' undefined but `SYNTAX_TABLE'
     defined, then Regex expects you to define a `char *' variable
     `re_syntax_table' to be a valid syntax table.

   * See Emacs Syntax Tables, for what happens when Regex is
     compiled with the preprocessor symbol `emacs' defined.