This sounds like a question I was asking myself a few weeks ago. Now that I've found
iCustom, I think it answers this sort of question. If you have the indicator, you can let
the EA use that indicator (any indicator) to trade with by accessing it with the
iCustom(). Then, you can see it without having the EA do indicator stuff.
Unless I misunderstood the question?
I haven't used it yet, so I'm strictly going on the MT4 documentation and the iCustom article here. It's my understanding that if you know the design of the indicator being referenced,
and the order of the values declared within it, then the iCustom can call those
values in real time for an EA's decisions. So far, though, I've re-built the indicator
my own way and used it within the EA, I haven't yet used iCustom, but I expect
I will as it seems it would save time.
One thing you might do is just write a test EA. Just have it call iCustom's various
values for a particular custom indicator of interest , and have it dump those values
out to the Journal with a print command, or have it call the object functions to
draw an arrow and text on the chart with the values so you can verify what value
is getting returned for what call, and it should line up with the graphic indicator
on the chart live. I might end up doing that to build confidence it's returning
what I expect it to. That would also be a way to figure out a custom indicator
if you don't have access to the .mq4 to read the design.
Good luck! --Matt