Create a function that "physically" touches a key of the keyboard

Objective: I want to use the signals of my expert advisor on another platform whose programming language does not allow a conversion because the onbook event does not exist. (no equivalent).

So I want to proceed as follows: 

Put the  trading platform i want to use in the foreground with two maccros, one for buy, one for sell.

In the mql5 expert advisor, where my buy and sell signals used to be, there will be the "press buy key" and "press sell key" functions. 

As the New plateform is in foreground , anytime the expert advisor will generate a buy signal for example , it will "physically" press the buy button , like a click or a key , so the signal is transmitted.

Another example just to be clear : if i open google chrome with the search bar on , and the expert advisor generates a buy signal , it will write in the search bar the key that has been set up for "buy signal".

It seems as i saw in the internet it should be something like using the "SendKey" function or something , but the programmer is free in his choice of the way he succeed the work.

One more thing : the programmer has to be careful that his function does not cost too much in execution time so that the operations are carried out in the best possible way, the expert advisor in which I want to integrate his functions generates his signals from OnBook events , so there can be 2 or  3  signal every 5  seconds without any problem.