[sv-bc] Issues on Queue Operators

Hi,
I have certain queries regarding queue operator ( IEEE standard 
1800-2005 LRM , section 5.14 ) .
1. Here it has been stated
    "The empty array literal {} is used to denote an empty queue."
my query :: Should this empty  array literal syntax not be treated as an 
assignment pattern and
          be preceded by an apostrophe( ' ) ?
2.
Further , for the example given in section 5.14.1 to explain Queue 
Operators ( which are not applicable to normal arrays )
    q ={q,6} ;
    q = {e,q};
    q = { q[0:pos-1], e, q[pos,$] };
    q = { q[0:pos], e, q[pos+1,$] };

Now, we can't have a unsized constant as a member of concat expression .
should the RHS be treated as concatenation or  assignment pattern  ?

3.Is the following case valid ?

module T; 
     int b[4:0];
    int c;
    int a[4:0] = '{b[3:0],c} ;
endmodule
   

Thanks,
Sharmistha