Lexical scope

Dart is a lexically scoped language, which means that the scope ofvariables is determined statically, simply by the layout of the code.You can “follow the curly braces outwards” to see if a variable is inscope.

Here is an example of nested functions with variables at each scopelevel:

bool topLevel = true;
void main() {
  var insideMain = true;
  void myFunction() {
    var insideFunction = true;
    void nestedFunction() {
      var insideNestedFunction = true;
      assert(topLevel);
      assert(insideMain);
      assert(insideFunction);
      assert(insideNestedFunction);
    }
  }
}

Notice how nestedFunction() can use variables from every level, allthe way up to the top level.