Groups vs Functions (zooming)

I'm trying to implement the cinematic zoom defined in this tutorial within functions rather than groups:

scirra.com/tutorials/254/cinematic-zoom

The reason for this is that I plan to pass in parameters to speed up/slow down the zoom based on the values of certain instance variables.

The problem is on turning this into a function, the code executes only once so zooms in/out partially on a key press rather than fully. Tried placing a the zoom value check in a while condition but it still only seems to execute once.

Any suggestions or alternative approaches appreciated.

Put the function call in a loop, or call it while a variable has a certain value. For example, if X=5 Call function. As long as X=5 then your function gets called every tick...