Writing custom functions

Writing custom functions is like writing procedures and functions in BASIC or a similar language. The following description of Fireworkz custom functions assumes that you have programmed in BASIC or a similar language. You will find it difficult to write working custom functions without this type of experience.

See the following:

The FUNCTION function

Custom function control statements

Naming custom functions

Parameters to FUNCTION

Declaring the result

Processing ranges of data

Recalculation and custom function sheets

Before you start to create your custom function, you should decide some important things about it:

Deciding all these matters in advance will make the process of creating the custom function much simpler. If you have thought it through in advance you are much more likely to write a function which works and produces the kind of results you anticipated.

A custom function sheet is not an ordinary worksheet. Formulae that you enter into custom function sheets are displayed on the sheet. They are displayed in different colour to the text to enable you to distinguish between formulae that have been entered correctly and formulae which have been entered as text because Fireworkz could not understand them.