id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
8187,Bug in phoenix docs and example code,Eric Niebler,Kohei Takahashi,"The example [http://www.boost.org/libs/phoenix/doc/html/phoenix/examples/transforming_the_expression_tree.html here] is leading people astray. It is not recursively applying the transformation for node types other than plus, minus, multiplies and divides. If the top-most node is not one of those, no transformation happens.

The default case shown is:

{{{
struct invert_actions
{
    template <typename Rule>
    struct when
        : proto::_ // the default is proto::_
    {};
};
}}}

I think it should be:

{{{
struct invert_actions
{
    template <typename Rule>
    struct when
      : proto::nary_expr<
            proto::_,
            proto::vararg<
                proto::when<proto::_, evaluator(proto::_, _context)>
            >
        >
    {};
};
}}}

I'm actually not quite sure how this works, but it seems to. Note that the problem would also need to be fixed [http://www.boost.org/libs/phoenix/example/invert.cpp here].

See [http://stackoverflow.com/questions/15077637/transforming-a-boost-c-phoenix-expression-tree] for a discussion.
",Bugs,closed,Boost 1.67.0,phoenix,Boost 1.52.0,Cosmetic,fixed,,