Let's say I get value from a prompt?

\prompt 'Write [Yes] or [No]

' store

Which does this,

Write [Yes] or [No] Yes

I can verify I have that works,

\echo :store Yes

But, I can't get it to work with \if

\if :store='Yes' unrecognized value "Yes=Yes" for "\if expression": Boolean expected

\prompt 's doc don't say much on this