Interaction of encoded-character extension with variables extension

[Stephan Bosch <[e-mail]>]

Hello,

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).

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 would make the 
following possible:

"${hex: 24 7B}foobar}"  ==> "${foobar}" ==> "Whatever the foobar 
variable holds."

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. 
Although the above example is pretty useless and very unlikely to occur 
in reality, I think it is appropriate for a specification to explicitly 
note what is to be done in this situation.

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.

Regards,

--
Stephan Bosch
[e-mail]