Re: Interaction of encoded-character extension with variables extension

[Kjetil Torgrim Homme <[e-mail]>]

On Fri, 2007-12-21 at 11:56 +0100, Stephan Bosch wrote:
> I am building a Sieve implementation and, while reading the new 3028bis 
> specification, I noticed the new encoded-character extension. Its 
> substitution syntax is somewhat similar to what the variables extension 
> defined ( i.e. ${....} ). I am currently working with 
> draft-ietf-sieve-3028bis-13 and draft-ietf-sieve-variables-08. Now I am 
> wondering how these extensions are supposed to work if both are active. 
> Niether specification mentions this possibility (variables-08 seems to 
> be pretty old already though).

you're right, this is my mistake, I forgot to add text to variables.

> One could define encoded-character substituion to be performed before 
> any variables substitution, making the variables substitution act upon 
> the result of the encoded character substitution.

this was the WG consensus when it was discussed in November 2006.  see
the thread "Invalid syntax to cause runtime error in encoded-character"

> Although this is (to my opinion) intuitively the most logical 
> implementation, I can imagine other options in which encoded character 
> and variables substituion is performed in parallel, making use of the 
> fact that both extensions use the same delimiters for marking a 
> substitution. This could make things more efficient, as only one pass is 
> needed to identify substitutions in the string. This makes the above 
> situation result in just "${foobar}" without further substitution.

if you are worried about performance, you byte-compile the script during
upload, and remove the encoded-characters then.

> Note that I am not trying to revive any old discussion on this topic. I 
> would just like to know what your opion is on this issue and I am hoping 
> that you could make this more explicit in the specification.

unfortunately, the variables draft is due to be published.  I guess
we'll have to leave it for the next version when/if it is progressed to
Draft Standard.

-- 
best wishes,
Kjetil T.