Re: Boost.URL -- some notes

From: Gavin Lambert (boost_at_[hidden])
Date: 2022-06-08 00:07:00

On 7/06/2022 23:21, Дмитрий Архипов wrote:
> There's no such thing as "URL protocol". 

I was using an abbreviation.  A more correct phrasing might be "an URI 
scheme that denotes a protocol that uses the URL format" but that's much 
more of a mouthful.

The parsing-level distinction between the two is generically obvious and 
does not require recognition of the specific scheme; if the scheme colon 
is immediately followed by one or more slashes then it's an URL, 
otherwise it is not.  But this is off-topic.

(Well, ok, *technically* the distinction is even more vague than this, 
and it's possible to have an 'URL' that doesn't lead with slashes -- it 
just needs to semantically represent a 'location' rather than a 
'name/id'.  But for practical purposes the above rule suffices, 
especially in the context of an URI parser, since it must treat the 
content as opaque if it does not have leading slashes.)

> And on the other hand, http scheme is usually associated with the
> idea of URL. But e.g. XML namespaces are identified by URIs, often
> those are http URIs, and there's absolutely no guarantee that the URI
> can be used to retrieve some document from the Internet.

They're still URLs, regardless of whether they resolve to a valid web 
resource or not.  (They're also URIs, of course.)