/* REGULAR EXPRESSION CONSTRUCTION MACROS
 *
 * $Id: re.h,v 1.2 2022/02/03 20:19:38 oj14ozun Exp $
 *
 * Inspired by and a weak immiation of Emacs Lisp's rx
 * macro.  */

#define or(re, er) "(?:" re "|" er ")"
#define maybe(re)  "(?:" re ")?"
#define multi(re)  "(?:" re ")+"
#define many(re)  "(?:" re ")*"
#define wmulti(re)  "(?:" re ")+?"
#define wmany(re)  "(?:" re ")*?"
#define repeat(re, n)  "(?:" re "){" #n "}"
#define multiple(re, n, m)  "(?:" re "){" #n "," #m "}"
#define most(re, n)  "(?:" re "){," #n "}"
#define least(re, n)  "(?:" re "){" #n ",}"
#define class(name) "[:" #name ":]"
#define group(re) "(" re ")"
#define any(chars) "[" #chars "]"
#define not(chars) "[^" #chars "]"
#define bol "^"
#define eol "$"
#define anything "."

/* Examples:
 *
 * multi(class(blank)) eol
 *
 * ~>	(?:[:blank:])+$
 * 
 * bol or(many(class(blank)) eol, "a" least("b", 4) multi(anything) eol)
 *
 * ~>	^(?:(?:[:blank:])*$|a(?:b){4,}(?:.)+$)
 */