Re: [Boost-users] [BGL] Bundled properties and property maps

Subject: Re: [Boost-users] [BGL] Bundled properties and property maps
From: Geoff Hilton (geoff.hilton_at_[hidden])
Date: 2009-01-14 19:47:19

Andrew Sutton wrote:
> 
> On Tue, Jan 13, 2009 at 9:56 AM, Andrew Sutton 
> <andrew.n.sutton_at_[hidden] <mailto:andrew.n.sutton_at_[hidden]>> wrote:
> 
>         Hi Andrew, apologies for writing directly to you, I just thought
>         I'd try to get your attention this way since you hadn't yet
>         replied to my last post on the above topic in the mailing list.
> 
>      
>     Sorry about that, I've been swamped since new years. I'm going to
>     bounce this back to the list
> 
>     I would avoid declaring property maps as const. Somewhere in your
>     posted code you have:
> 
>     const property_map<...>::const_type map; // or something similar.
> 
>     For all property maps, map = get(...) is a valid expression,
>     regardless of whether your map is a ::type or ::const_type. By
>     declaring it const, and then instantiating a template with the const
>     pmap, you're going to run into problems - probably the problem you
>     reported earlier.
> 
>     Andrew Sutton
>     andrew.n.sutton_at_[hidden]

Okay, so if I understand correctly I shouldn't use const prop maps with 
const_type at all?

It seems to me like a line such as the above should still theoretically 
compile. At least from the perspective of a concept check for 
Readability; this is by definition what const is meant to restrict 
objects to so in theory in should be allowable no? If I'm right it would 
be a compilation error caused by the underlying implementation. Either 
that or a debatable foible that should be documented? *shrug*.

Thanks,
Geoff