Creating a new Symbol from two strings with a point

General Usage
4

Please see PSA: how to quote code with backticks.

That eval operates on global scope. From what you have shown so far there is no need for any of this parse + eval stuff, just do something like:

mutable struct MyType
    a::Int
    b::Int
end

function foo!(B::MyType)
   var1 = "b = 10" # from data file
   sym, val = strip.(split(var1, "="))
   setproperty!(B, Symbol(sym), parse(Int, val))
end

with the result

julia> B = MyType(1, 2)
MyType(1, 2)

julia> foo!(B)
10

julia> B # B.b has been changed
MyType(1, 10)