IF statement based on string contents of a scalar

[Saeed Sardar]

I am trying to write a program, that has option flist(string), where flist can take words such ri rm etc. Now suppose the user specifies flist(ri). How can I supply this flist macro to mata function and see there whether the user has specified ri or rm. I tried the following inside the mata function, but it returned the following error.

flist="ri"
if(flist="ri") "option is ri" ; ;
 <istmt>:  3250  type mismatch

my question is how to evaluate a string scalar through if statement.

[Joseph Coveney]

In Stata, generally, and in Mata, generally, a single equals sign means assignment. You'll want two equals signs when testing a condition. So,

if (flist == "ri") . . .