%v:EXPR% (is|is not) set
Checks if a value is null or not null.
if myVar is set:
if myVar is not set:
Every distinct way you can write this pattern, with optional groups and choice groups expanded. Placeholders are shown as <name>.
<v> is set
<v> is not set
%a:EXPR% %op:OP% %b:EXPR% for %scope:EXPR%
%a:EXPR% (is|equals) %b:QSTRING% for %scope:EXPR%
%a:EXPR% (is not|does not equal) %b:QSTRING% for %scope:EXPR%
%a:EXPR% is set for %scope:EXPR%
%a:EXPR% is not set for %scope:EXPR%