Nested scopes

Scopes can be nested, don't confuse this statement with "libraries can be nested", in fact, you cannot even place a library inside an scope definition. You can however, have scope inside either library or scope definitions.

An scope inside another scope is considered a child scope. A child scope is considered to be a public member of the parent scope (?).

A child scope cannot declare members that were previously declared as private or global by a parent scope.

A child scope behaves in relation to its parent in the same way as a normal scope behaves in relation to the whole map script.

Since child scopes are always public members, you can access a child scope' public members froum outside the parent scope, but it needs a prefix for the parent and a prefix for the child.

An example :

library nestedtest
    scope A
      globals
        private integer N=4
      endglobals

      public function display takes nothing returns nothing
        call BJDebugMsg(I2S(N))
      endfunction
    endscope

    scope B
        globals
            public integer N=5
        endglobals

        public function display takes nothing returns nothing
            call BJDebugMsg(I2S(N))
        endfunction
    endscope

    function nestedDoTest takes nothing returns nothing
        call B_display()
        call A_display()
    endfunction

endlibrary

public function outside takes nothing returns nothing
    set nestedtest_B_N= -4
    call nestedDoTest()
    call nestedtest_A_display()
endfunction

The next example will cause a syntax error:

library nestedtest
    globals
        private integer N=3
    endglobals

    scope A
      globals
        private integer N=4 //Error: 'N' redeclared
      endglobals
    endscope

endlibrary

It is actually caused by a limitation in the parser, there is a conflict caused by using N for the parent and then declaring it for the child. However this version does not cause syntax errors:

library nestedtest
    scope A
      globals
        private integer N=4
      endglobals
    endscope

    globals
        private integer N=3
    endglobals

endlibrary

It does kind of the same thing, but since the child's N was declared before the parent's the parser no longer gets in a confusion.

Another thing to keep in mind is that unlike normal global variables, private/public global variables cannot be used before declared, otherwise JassHelper will think they are just normal variables.

Scopes cannot be redeclared, there cannot be 2 scopes with the same name. But 2 child scopes might have the same name if they are children of different scopes, the reason is that they actually don't have the same name, they have different names given by their public child scope situation.

library nestedtest
  scope A
    function kkk takes nothing returns nothing
        set N=N+5  // By the time JassHelper gets to this line, it did not see the private integer N
                   // declaration yet, so it assumes N is an attempt to use a global variable and does not
                   // do any replacement
    endfunction
  endscope
endlibrary

scope X
   scope A
      //Declaring scope A again does not cause any problem, it is because the scope is actually X_A , the
      // previous declaration of A was actually nestedtest_A
      function DoSomething takes nothing returns nothing
      endfunction
   endscope
endscope

There is no nesting limit, but notice that resulting variable and function names of private/public members get big and bigger depending of the depth of the scope nesting. Bigger variable names may affect performance. Not a lot but they do, and this efficiency issue is to be prevented by an obfuscator/finalizer that renames every identifier in the map script a.k.a the map optimizer's shortest names possible method.

Last modified: 16 October 2024