Eric Blake <e...@byu.net> wrote: > According to Jim Meyering on 1/10/2009 10:48 AM: >> "[" feels like it should be the exception. >> I see treating --v like --version as a feature. a typing saver. >> But with "[", it's good to minimize the number of strings that >> make it act differently. >> >> Besides, why make everyone type it all out if there's no need? > > Then maybe the better approach would be adding a parameter to > parse_long_options (or rather, creating a new function with an extra > parameter, and making parse_long_options default to calling it with the > parameter at 0, but make echo and [ call it with the parameter set to 1), > where having the parameter set controls whether --h is ignored (the > exception, for echo) or treated as an abbreviation (the rule, for things > like basename). > > Or, for echo and [, we could skip parse_long_options altogether, and > hardcode this instead: > > argc == 2 && (STREQ (argv[1], "--help") || STREQ (argv[1], "--version"))
One of those approaches would be good. Whichever you prefer. >> Then you don't have to "know" that a program accepts only >> --help and --version, and hence accepts no abbreviations, >> versus those that accept at least one more long option, which >> do provide the feature. >> >> Also, it'd mean adding a third option would have >> the side effect of enabling --h and --v recognition. > > That's kind of what happened with expr vs. factor. Since > parse_long_options only recognizes exactly one argument as a long option, > adding another option already has a side effect: > > $ src/factor --help | head -n1 > Usage: src/factor [NUMBER]... > $ src/factor --help --version | head -n1 > Usage: src/factor [NUMBER]... > $ src/expr --help | head -n1 > Usage: src/expr EXPRESSION > $ src/expr --help --version | head -n1 > src/expr: syntax error > > expr currently uses parse_long_options, while factor does not; therefore > factor is able to handle --help --version while expr is not. I see it the other way ;-) factor mistakenly accepts the combination of --help --version. Actually, I see a small problem: factor doesn't document in --help output the relatively new --verbose option. And expr is similar to test and "[" in accepting arbitrary strings, so it minimizes the impact of accepting --help and --version. > Maybe parse_long_options should be taught to recognize multiple options > that all match an abbreviation of --help/--version, rather than expecting > exactly one option? I think of --help and --version are exclusive, since by definition each prints something and exits. So it doesn't make sense to use them together.
