====== Group declaration ======
===== group_declaration =====
<code vhdl>group identifier : group_ template _name ( group_constituent_list ) ;</code>

===== Parents =====
  * entity_declarative_part
  * architecture_declarative_part
  * configuration_declarative_part
  * package
  * package_body
  * block_declarative_part
  * function_declarative_part
  * procedure_declarative_part
  * process_declarative_part

===== Further definitions =====
==== group_constituent_list ====
  group_constituent { , group_constituent }

==== group_constituent ====
  * [[.:bnf#name]]
  * [[.:bnf#character_literal]]

===== Examples =====
Groups of type //pin2pin// are declared.
<code vhdl>GROUP pinpair1 : pin2pin (clk, q1) ;</code>
<code vhdl>GROUP pinpair2 : pin2pin (clk, q2) ;</code>

----

A group of the former declared groups.
<code vhdl>GROUP clocked : gog (pinpair1, pinpair2);</code>

----

  * The group template //path// is declared.
  * The group //a_to_s// is declared.
  * The attribute //propagation_delay// is declared.
  * The attribute //propagation_delay// is assigned to //a_to_s// and is given the value of 250 ns.
<code vhdl>
GROUP path IS ( SIGNAL , SIGNAL ) ;
GROUP a_to_s : path (a,s) ;

ATTRIBUTE propagation_delay : time ;
ATTRIBUTE propagation_delay OF a_to_s :
               GROUP IS 250 ns ;
</code>

----

  * The group template //pin_set// is declared.
  * The gourp template //paths// is declared.
  * The group of signals //sources// and //targets// are declared.
  * The group of groups //ins_to_outs// is declared.
  * The attribute //propagation_delay// is declared.
  * The attribute //propagation_delay// is assigned to //ins_to_outs// and is given the value of //delay// .

<code vhdl>
GROUP pin_set IS ( SIGNAL <>) ;
GROUP paths IS ( GROUPS <>) ;

GROUP sources : pin_set (inp1, inp2) ;
GROUP targets : pin_set (outp1, outp2) ;
GROUP ins_to_outs : paths (sources,
                           targets) ;

ATTRIBUTE propagation_delay : time ;
ATTRIBUTE propagation_delay OF
          ins_to_outs : GROUP IS delay ;
</code>