objective c - DDMathParser - Using a string as an argument in a custom function -

i make function allow me pass string in argument - what's best way this?

eg.. moles("ca(oh)2")

any extremely gratefully received.

i ended putting in parsing strings variables. ddmathparser:

somefunction("hello") 

... equivalent to:

somefunction($hello) 

however, means can have variables more complex stuff:

somefunction("hello world") moles("ca(oh)2") 

... etc