I want to build a long command line.

This works OK:

TEXT TO dothis
cmsg = 'A' + 'B'+ 'C'
ENDTEXT

&dothis
?cmsg

Now trying to build a multi-line command:

TEXT TO dothis
cmsg = 'A' + ;
'B'+ 'C'
ENDTEXT

&dothis
?cmsg

This gives an error (with or without the semi-colon). Is there a way to build up a command over more than one line?
Cyril