LOOPIF <word-param-list> VALID ...
LOOPIF [<$-word>=] <group-param-list> VALID ...
For a word parameter list, <statements1> are executed for each word in the list which is present in the event.
For a group parameter list, <statements1> are executed for each group in the list which is present in the event. If the optional "<$-word>=" is specified in the command then the group identifier is assigned to the <$-word> variable for each iteration of the loop.