AMDG On 04/05/2011 04:52 PM, Lorenzo Caminiti wrote:
On Sun, Apr 3, 2011 at 2:22 PM, Steven Watanabe<watanabesj@gmail.com> wrote:
On 04/03/2011 11:13 AM, Lorenzo Caminiti wrote:
Boost.Local uses a special name `this_` to access the object `this` bound from the enclosing scope. Shall this name be `this_` or `_this` according to Boost practices?
struct c { void g(int x) { ... } void f() { void BOOST_LOCAL_FUNCTION_PARAMS( (int x) (bind this) ) { this_->g(x); //<<<<<<<<< Shall this be `_this->g(x);` instead? ... } BOOST_LOCAL_FUNCTIO_NAME(l) ... } ... };
In particular, some library uses _ postfix for statements like mpl::if_ (not mpl::_if) while other uses _ prefix for variables like phoenix::local_names::_f (not local_names::f_).
The convention is that _xxx is used for placeholders. xxx_ is used when xxx is a keyword.
1) What is the exact definition of a "placeholder"?
A placeholder is an object or type which is intended to be replaced by another object or type. Some Examples of placeholder objects are _1, _2, etc, used in bind, lambda, and phoenix. Examples of placeholder types are mpl::_1, and boost::recursive_variant_. I would not consider this_ a placeholder here.
2) What is the convention for an xxx that is both a keyword and a placeholder?
The situation hasn't come up. In Christ, Steven Watanabe