Author: Stan Eisenstat
Subject: Re: [Cs323] Assignment when is defined
Date: Tuesday, 13 Oct 2020, 07:59:18

    > Message Posted By: Unknown
    >
    > When i execute the command sequences
    >
    > % /c/cs323/Hwk3/mcBash
    > (1)$ ${ONE=1}
    > >> 1
    > (2)$ ${TWO=${ONE=${ZERO=0}}}
    > >> 1
    > (3)$ $TWO
    > >> 1
    >
    > It seems TWO is still being assigned the value of ONE, even though ONE was
    > previously defined. However the spec says "However, if NAME exists, then
    > during the expansion mcBash must suppress any assignments to environment
    > variables...", so I was expecting TWO to have no value, since the
    > assignment to ONE will cause assignments to be suppressed. Can you please
    > explain this?

Since ONE is undefined, "${ONE=1}" sets ONE to "1" and
is replaced by "1".

Since TWO is undefined, "${TWO=${ONE=${ZERO=0}}}" sets
TWO to the value of "${ONE=${ZERO=0}}" and is replaced
by it.

Since ONE is defined as "1", "${ONE=${ZERO=0}}" does
not change the value of ONE and its value is also "1".
Moreover, it does not assign a value to ZERO.

--Stan-