/*
 * subst.h - Substitution rules
 *
 * Copyright 2012 by Werner Almesberger
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */


#ifndef SUBST_H
#define	SUBST_H

#include <stdio.h>
#include <sys/types.h>
#include <regex.h>

#include "relop.h"


#define	NMATCH	10	/* $0 (not used), $1...$9 */


enum chunk_type {
	ct_string,
	ct_var,
	ct_sub,
};

struct chunk {
	enum chunk_type type;
	union {
		const char *s;
		const char *var;
		int sub; /* 0 if $$ */
	} u;
	struct chunk *next;
};

enum subst_type {
	st_match,	/* try to match a variable */
	st_assign,	/* assign to a variable */
	st_end,		/* end the substitutions, accepting the part */
	st_ignore,	/* ignore the part */
	st_break,	/* jump to an outer block */
	st_continue,	/* repeat an outer block */
};

struct subst {
	enum subst_type type;
	union {
		struct {
			const char *src;
			regex_t re;
			struct subst *block;
			char units[NMATCH-1];
		} match;
		struct {
			const char *dst;
			enum relop op;
			struct chunk *pat;
		} assign;
		const struct subst *jump;
		const char *tmp; /* jump target name; for subst_finalize */
	} u;
	const struct subst *prev; /* for tracking availability of variables */
	struct subst *next;
};


#define	MULT_CHARS	"GMkmunpf"


struct subst *subst_match(const char *src, const char *re);
struct subst *subst_assign(const char *dst, enum relop op, const char *pat);
struct subst *subst_end(void);
struct subst *subst_ignore(void);
struct subst *subst_break(const char *block);
struct subst *subst_continue(const char *block);

void subst_finalize(struct subst *sub);

void subst_dump(FILE *file, const struct subst *sub);

#endif /* !SUBST_H */