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• Parse-expressions

Vl-parse-any-sort-of-concatenation

Match single, multiple, or streaming concatenations, or empty queues.

Signature

(vl-parse-any-sort-of-concatenation &key (tokstream 'tokstream) 
                                    (config 'config)) 
 
  → 
(mv errmsg? value new-tokstream)

Arguments

config — Guard (vl-loadconfig-p config).

Both Verilog-2005 and SystemVerilog-2012 agree on the syntax for concatenations and multiple concatenations:

concatenation ::= '{' expression { ',' expression } '}'

multiple_concatenation ::= '{' expression concatenation '}'

By itself this is slightly tricky to parse: we don't know which production we're matching until we have read the initial '{' expression . If we then find a comma, or a closing brace, we know it is a single concatenation. Otherwise, if we find an opening brace, we know it is a multiple concatenation.

SystemVerilog-2012 complicates this by adding streaming concatenations:

streaming_concatenation ::=
  '{' stream_operator [slice_size] stream_concatenation '}'

stream_operator ::= '>>' | '<<'

Fortunately, streaming concatenations are easy to identify because they always start with one of these stream_operators.

SystemVerilog also adds empty queues which are easy to identify:

empty_queue ::= '{' '}'