Re: Parser interface design

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Tue, 12 Apr 2011 16:13:30 +0000 (UTC), Natasha Kerensikova wrote:

> On 2011-04-08, Simon Wright <simon@pushface.org> wrote:

>> In other words, HTML.Emphasize ("bar") would return "<b>bar</b>", but
>> No_Op ("bar") would just return "bar".
> 
> And that's exactly why disabling emphasis should be done on the parser
> level: the callback only has the semantic information ("render bar
> emphasized") without any knowledge of how it was obtained (the source
> could have been "foo *bar* baz" or "foo _bar_ baz"). Therefore no
> callback can reconstruct the intact input.

That looks wrong to me. I think that obvious design is to move it to the
renderer:

   HTML.Emphasize ("bar")  -> "<b>bar</b>"
   ASCII.Emphasize ("bar")  -> "*bar*"
   Plain_Text.Emphasize ("bar")  -> "bar"
   Gtk_Text_Buffer.Emphasize ("bar")  -> sets tags around the text slice
   ...

Parser just calls On_Emphasize, the implementation of routes it to the
renderer's Emphasize, which figures out what to do.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de