From: Vladimir Prus (ghost_at_[hidden])
Date: 2004-09-18 04:12:32
Jonathan Graehl wrote:
> Actually, I was suggesting that a value for an option that doesn't
> accept one, would be a parse error. Otherwise you have possible
> confusion with user thinking it's a value<bool> and by saying foo=false,
> you mean the same thing as not specifying the "foo" switch.
> What's the use of an option with an OPTIONAL value? :) Wouldn't you
> just omit the option and use the default value if you didn't want to
> provide one? It should be possible to specify options, at command line
> or in config file, that have no value; their presence or absence (often,
> commented or uncommented in standard practice) would determine the value.
It's possible for the absense of option and presense of option with no
explicit value to mean different things.
- no '--compression' means no compression
- ' just '--compression' means default compression level
- '--compression=4' means the specified compression level
But one has to try hard to achieve this behaviour. I though about removing
optional values at some time, but never got to this. What do the users
think? Does anybody need optional values?
> I mean, a config file could have:
> (not bool_switch_opt=something)
Yea, that's a possibility.
> It would be perfectly pleasing to me though, to allow bool_switch to
> have a true or false value in a config file, and not at the command
> line. However, that would violate the existing design, wouldn't it?
Right, that's why I'm not sure what to do. There's a related issue. It's no
possible to specify a list of things in config file. For example, you can't
(or some other separator). You need:
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