Problem by using String Var in embedded SQL where criteria

Hallo, I am new on programming Object Script.

My problem: How can I use a String variable in embedded SQL?

The below example does not work by using: namevar with ' ' 

set namevar = 'Ali'

&sql(DECLARE C2 CURSOR FOR SELECT name INTO :name FROM person where name = 'namevar')

Only below will work: person where name = 'Ali' 

Thanks in advance