That's not what he wants to do. He wants to preserve all of the pipes, and
insert a space between any two consecutive pipes with no other data between them.
Presumably the position of his toks must be maintained.
I am still struggling with regex, but this seems to work:
alias TR {
var -s %test = |a|b|c||||d|||e|||
var %testReg = /\|(?=\|)/Sig
noop $regsub(Blah,%test,%testReg,$+($chr(124),$chr(32)),%TestOutput)
/echo -ag %Testoutput
}