[sv-ac] question on subroutines on empty sequences

I have a question. If there is a "sequence_match_item" associated with a
potentially empty sequence, does it get executed when the sequence is
empty?  Given the example in the std, there could be a
sequence_match_item associated with the potentially empty seq
(potentially empty meaning  a repetition range like [*0:3])  and also a
sequence_match_item associated with the "seq".  Are both executed
simultaneously?

 

Starting on page 293 of the document, page 259 of the pdf,  it states:

 

" Using 0 as the repetition number, an empty sequence results, as
follows:

a [*0]

 

An empty sequence is one that does not match over any positive number of
clock ticks. The following rules

apply for concatenating sequences with empty sequences. An empty
sequence is denoted as empty, and a

sequence is denoted as seq.

- (empty ##0 seq) does not result in a match.

- (seq ##0 empty) does not result in a match.

- (empty ##n seq), where n is greater than 0, is equivalent to (##(n-1)
seq).

- (seq ##n empty), where n is greater than 0, is equivalent to (seq
##(n-1) 'true).

 

For example:

b ##1 ( a[*0] ##0 c)

produces no match of the sequence.

 

b ##1 a[*0:1] ##2 c

is equivalent to

(b ##2 c) or (b ##1 a ##2 c)

 

Lisa

 


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