Hi Jonathan,
here's another possibility:
value<type>(&variable, "filename")->......
something like that was in the pre-review version, with the difference that the value name was also used to specify flags, e.g "filename?" would mean the value is optional.
Yes ... I like this best.
Ok, noted.
Also, I'm not sure why 0-argument items couldn't appear in a config file. I declare the number of arguments used by options before I parse the config file, after all.
Because the current config parser, systantically, requires that everything specified there has a value. If you specify that an option accepts no explicit value, it can't be present in config file.
OK, your statement was with reference to the current config parser ;)
Sure.
A newer parser could recognize the end of an option name first, then interrogate the option to see if it takes an argument, then if it does, expect to parse a "= value".
Hmm... that would mean that you can specify a value in config file for an option which does not allow a value? E.g. ("foo", bool_switch().... and then in config file: foo=false then "false" will be just ignored? OTOH, it might be reasonable to decide that the desired number of tokens applies only to command line, since other sources don't have any parsing ambiguities. - Volodya