Are Jsonnet variables, the ones that end with a semicolon (as opposed to the ones that end with a comma), the same as functions with no parameters?

In the following Jsonnet program

{
    c: local a = function() self.b; {x: a(), b: 'inner'},
    b: 'outer'
}

this is indeed the case, since it manifests the same as the program

{
    c: local a = self.b; {x: a, b: 'inner'},
    b: 'outer'
}

namely

{
   "b": "outer",
   "c": {
      "b": "inner",
      "x": "outer"
   }
}

But is this generally the case? Can I make a rule out of it?