Applying one indicator to another

[Dave Hughes]

I am trying to use a custom indicator HMA to smooth the line of another indicator. I have found a couple of different implementations of HMA in Codebase: one is based on SmoothAlgorithms.mqh

(the code is at https://www.mql5.com/en/code/549), and the other uses a function iLWMA (on buffer), which is in the same file as the hma indicator (https://www.mql5.com/en/code/135). Both HMA's work on the chart. However, if I use the HMA based on SmoothAlgorithms.mqh to smooth , for example, RSI, it works.

Here is the code I use to create the handles: 

 RSIHandle=iCustom(_Symbol,PERIOD_CURRENT,"RSI",RSI_Period);

 HmaHandle = iCustom(NULL, 0, "hma", MA_Period, RSIHandle);

The other hma based on iLWMA still outputs an HTML line instead of a smoothed RSI line.

I would appreciate it if someone, who is more experienced with mql5 could take a look at the code of those indicators using the links I provided and would explain why the hma based on the iLWMA on buffer function fails to smooth another indicator provided as the last argument to iCustom.