On Fri, Dec 25, 2015 at 2:07 PM Masakatsu ITO(伊藤) <itoh.masakatsu@jaxa.jp> wrote:

Actually I tried to adapt my DiffereneceOperator type to Proto
as Proto Users Guide explains in "Adapting Existing Types to Proto".


I think this didn't work because the macro doesn't overload the function call operator.

And I wondered when it is necessary to write a code such like

calculator< proto::terminal< placeholder<0> >::type > const _1;

in "The extends< > Expression Wrapper".


This is needed to make sure the terminal is part of the calculator domain, if you leave out the calculator<> part you just get an expression in the default domain.

Wishing you a merry Christmas,

Merry Christmas to you too!