st: Adding variables with common prefix

["R.E. De Hoyos" <redeho@hotmail.com>]

I have a large list of variables with a common prefix, say -var- (var1, 
var2, var3...). I want to generate a scalar with the sum of these variable's 
first observation. I tried the following loop, but for some reason that I 
can't see it is not working, it returns an invalid syntax error message:

local sum = 0
foreach v of var* {
   local sum = `sum' + `v'[1]
}
scalar answer = `sum'

What is wrong with this code? Is there an alternative way of adding up 
variables with a common prefix?

Rafa
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