[Help-bash] Anomalies with ${*}

[Bill Gradwohl]

Sorry for building on my last email, but I found some other anomalous behavior with ${*}.

abc='  '
echo "->${abc}<-"
echo "->${abc// /}<-"

set -- '' '' ''
echo "->${*}<-"
echo "->${*// /}<-"

IFS='' set -- '' '' ''
echo "->${*}<-"

IFS= set -- '' '' ''
echo "->${*}<-"

IFS=''
set -- '' '' ''
echo "->${*}<-"

IFS=
set -- '' '' ''
echo "->${*}<-"

Every one of the echo's referencing * should be a null string as far as I can tell, but some aren't. 

Why does nulling out IFS work as a separate statement, but not on the same line? 

It works when IFS='' precedes read on the same line, so why not before set?

The reason I'm doing this is to see if all the passed parameters are null strings.

I'm sure there's a man bash exception I missed somewhere, but where?

Thank You

-- 
Bill Gradwohl