#ifndef LEX_H
#define LEX_H

enum lexcode {
	Lok = 1,
	Lerror,
	/* Returned when lexer could not produce any tokens from
	 * current input, but no error was detected either */
	Lmore,
};

struct lexresult {
	enum lexcode res;
	union {
		struct token token;
		char *errmsg;
	};
};

/**
 * lexbuf is a sans-io implementation. The user must provide input
 * bytes and a length.
 */
struct lexstate {
	u8 buf[4096];
	usize pos; /* current position in buffer */
	usize len; /* user-provided length of input */

	/* already lexed tokens that aren't yet consumed */
	struct lexresult results[4096];
	usize nres;
	usize respos;

	/* line and column info */
	usize lineno;
	usize column;
};

struct lexresult lex(struct lexstate *);
void lexreset(struct lexstate *);
void lexfeed(struct lexstate *, usize len, u8 *data);

#endif