Custom MQL4 Aroon Indicator and a separate script calling this indicator

Hi ,

I would like to have custom aroon indicator in mql4 that should be easily called in the code as well like other standard indicators.

for example  M_0 = iStochastic(NULL,0,5,3,3,MODE_SMA,0,MODE_MAIN, 0);// 0 bar

similarly i want  Aroon_Up=iAroon(Null,0,....) and Aroon_Down=iAroon(NULL,0,......); 

For the script I need boolean functions. 

the booleans should  detect aroon up crossing over aroon down  and their levels of crossing which all should be able to be user modifiable with externs.