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:

  1. bool topLevel = true;
  3. void main() {
  4.   var insideMain = true;
  6.   void myFunction() {
  7.     var insideFunction = true;
  9.     void nestedFunction() {
  10.       var insideNestedFunction = true;
  12.       assert(topLevel);
  13.       assert(insideMain);
  14.       assert(insideFunction);
  15.       assert(insideNestedFunction);
  16.     }
  17.   }
  18. }

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