lexer-callbacks.h

#ifndef LEXER_CALLBACKS_H
#define LEXER_CALLBACKS_H

struct arena_scope;
struct lexer;

struct lexer_callbacks {
	/*
	 * Read callback with the following semantics:
	 *
	 *     1. In case of encountering an error, NULL must be
	 *        returned.
	 *     2. Signalling the reach of end of file is done by
	 *        returning a token with type LEXER_EOF.
	 *     3. If none of the above occurs, the next consumed token
	 *        is assumed to be returned.
	 */
	struct token	*(*read)(struct lexer *, void *);

	/*
	 * Allocate a new token from the given arena scope.
	 * Expected to be initialized using the given token.
	 */
	struct token	*(*alloc)(struct arena_scope *,
	    const struct token *);

	/*
	 * Serialize routine used to turn the given token into something
	 * human readable.
	 */
	const char	*(*serialize_token)(const struct token *,
	    struct arena_scope *);

	/*
	 * Serialize routine used to turn the given token type into something
	 * human readable.
	 */
	const char	*(*serialize_token_type)(int, struct arena_scope *);

	/*
	 * Serialize routine used to turn the given token prefix into something
	 * human readable.
	 */
	const char	*(*serialize_prefix)(const struct token *,
	    struct arena_scope *);

	/*
	 * Returns the end of the branch associated with the given token.
	 */
	struct token	*(*end_of_branch)(struct lexer *, struct token *, void *);

	/*
	 * Move all prefixes from one token to another.
	 */
	void		 (*move_prefixes)(struct token *, struct token *);

	/*
	 * Informative callback invoked once all tokens are read.
	 * May be omitted.
	 */
	void		 (*after_read)(struct lexer *, void *);

	/*
	 * Informative callback invoked before freeing the lexer.
	 * May be omitted.
	 */
	void		 (*before_free)(struct lexer *, void *);

	/* Opaque argument passed to callbacks. */
	void		*arg;
};

#endif /* !LEXER_CALLBACKS_H */