anchor.diff:  	goto MACRO_ERROR
   )
   
  -call ok.bat
  +call  %~dp0%ok.bat
   %ifError% (
   
   	goto MACRO_ERROR
  
positive.code: )
  
  echo execute %~n0...
  
  
  @rem --------------------------------------------------------------------------------
  @rem ---
  @rem ---   Load prerequisites
  @rem ---
  
  call define-constants.bat
  if "%ERRORLEVEL%"=="0" (
  
  	@rem OK
  
  ) else (
  
  	goto MISSING_CONSTANTS_ERROR
  )
  
  
  @rem ================================================================================
  
negative.code: @rem ---
  @rem ---   A macro to check the error level.
  @rem ---
  
  set macroName=ifError
  echo %TAB%define %macroName%
  set "%macroName%=set foundErr=1&(if errorlevel 0 if not errorlevel 1 set foundErr=)&if defined foundErr"
  
  call  %~dp0%error.bat
  %ifError% (
  
  	@rem OK, the macro works
  