Subject: Re: [PATCH v2 2/4] stripspace: Use parse-options for command-line parsing

From: Junio C Hamano <[email-masked]>
Date: Fri, 16 Oct 2015 10:07:34 -0700

Tobias Klauser <[email-masked]> writes:

> Use parse-options to parse command-line options instead of a
> hand-crafted implementation.
>
> This is a preparatory patch to simplify the introduction of the
> --count-lines option in a follow-up patch.

The second paragraph is probably of much lessor importance than one
thing you forgot to mention: the users can now use a unique prefix
of the option and say "stripspace --comment".

> +enum stripspace_mode {
> +	STRIP_DEFAULT = 0,
> +	STRIP_COMMENTS,
> +	COMMENT_LINES
> +};
>  
>  int cmd_stripspace(int argc, const char **argv, const char *prefix)
>  {
>  	struct strbuf buf = STRBUF_INIT;
> -	int strip_comments = 0;
> -	enum { INVAL = 0, STRIP_SPACE = 1, COMMENT_LINES = 2 } mode = STRIP_SPACE;
> -
> -	if (argc == 2) {
> -		if (!strcmp(argv[1], "-s") ||
> -		    !strcmp(argv[1], "--strip-comments")) {
> -			strip_comments = 1;
> -		} else if (!strcmp(argv[1], "-c") ||
> -			   !strcmp(argv[1], "--comment-lines")) {
> -			mode = COMMENT_LINES;
> -		} else {
> -			mode = INVAL;
> -		}
> -	} else if (argc > 1) {
> -		mode = INVAL;
> -	}
> -
> -	if (mode == INVAL)
> -		usage(usage_msg);

When given "git stripspace -s blorg", we used to set mode to INVAL
and then showed the correct usage.  But we no longer have a check
that corresponds to the old INVAL thing, do we?  Perhaps check argc
to detect presence of an otherwise ignored non-option argument
immediately after parse_options() returns?

> -	if (strip_comments || mode == COMMENT_LINES)
> +	enum stripspace_mode mode = STRIP_DEFAULT;
> +
> +	const struct option options[] = {
> +		OPT_CMDMODE('s', "strip-comments", &mode,
> +			    N_("skip and remove all lines starting with comment character"),
> +			    STRIP_COMMENTS),
> +		OPT_CMDMODE('c', "comment-lines", &mode,
> +			    N_("prepend comment character and blank to each line"),
> +			    COMMENT_LINES),
> +		OPT_END()
> +	};
> +
> +	argc = parse_options(argc, argv, prefix, options, stripspace_usage,
> +			     PARSE_OPT_KEEP_DASHDASH);

What is the point of keep-dashdash here?