up previous next
perform commands in non-active ring
Using R Do Cmds EndUsing
where R is the identifier for a ring and Cmds is a sequence of commands.
|
Suppose S is the current ring and R is another ring, then
Using R Do
Command1;
Command2;
EndUsing;
is equivalent to
Use R;
Command1;
Command2;
Use S;
Use S ::= QQ[x,y]; -- the current ring is S
R ::= QQ[a,b,c]; -- another ring
Using R Do PrintLn Indets(); EndUsing;
[a, b, c]
-------------------------------
|
Note that you cannot create a new ring with this command:
for instance
Using QQ[a,b] Do ... EndUsing; will produce an error.
Instead you need to name the ring first, like this:
MyRing ::= QQ[a,b]; Using MyRing Do ... EndUsing;