print ("adf","ff","f"); # Gladly prints the list
print ("adf","ff","f")[1]; #Gives a syntax error
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Think to print() as a subroutine: you can write myfunc(...); but myfunc(...)[1]; is wrong.

With a "gift package ( )", perl will be happy: myfunc( (...][1] );

perl -e 'sub myfunc { return @_;}; my @res = myfunc('a','b','c')[1];print @res;' WRONG