Re: [Qi] Phrase parsed but iterator did not reach end

On Fri, Nov 24, 2017 at 6:42 PM, Michael Powell <[email protected]> wrote:
> Hello,
>
> Or the iterator backtracked?
>
> Is it possible for a phrase to parse (returns true), but the iterator
> does not reach the end, or was backtracked?
>
> Depending on the rule, of course. For which I currently have:
>
> boost::spirit::qi::rule<Iterator> _port_rule;
>
> _port_rule = digit
>     | (char_('1', '5') >> repeat(1, 4)[digit])
>     | (char_('7', '9') >> repeat(1, 3)[digit])
>     | (char_('6')
>         >> ((char_('0', '4') >> repeat(0, 3)[digit])
>             | (char_('6', '9') >> repeat(0, 2)[digit])
>             | (char_('5')
>                 >> ((char_('0', '4') >> repeat(0, 2)[digit])
>                     | (char_('6', '9') >> -digit)
>                     | (char_('5')
>                         >> ((char_('0', '2') >> -digit)
>                             | char_('4', '9')
>                             | (char_('3') >> char_('0', '5'))
>                             )
>                         )
>                     )
>                 )
>             )
>         )
>     ;

I'm not sure why repeat doesn't work quite right, or perhaps the user
is failing to grasp its effects. There aren't a ton of cases, and I
was able to separate them adequately.

So instead of:

(char_('1', '5') >> repeat(1, 4)[digit])

I was able to do this type of thing:

(char_('1', '5') >> -(digit >> -(digit >> -(digit >> -digit))))

Did that throughout, and fleshed out the tree in a little better depth.

Now it works, and the iterator reports to the end as expected, whereas
before the iterator would not.

> Where Iterator is a Struct Template argument.
>
> Basically to validate all the patterns from 0-65535 (valid port range).
>
> Cheers,
>
> Michael Powell

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