FileMaker® 12 Developers Reference: Functions, Scripts, Commands, and Grammars

Chapter 11. Custom Function Primer

Custom functions are, without a doubt, one of the most powerful features in FileMaker; we cannot advocate their use strongly enough. If you use FileMaker Pro Advanced, you can author or edit custom functions. After you add a function to a file, however, it becomes available to any user or developer who has access to a calculation dialog, be it in the service of tasks such as defining fields, writing scripts, or even performing calculated replaces.

After custom functions are added to a file, they become available for use in the calculation dialog alongside the built-in functions. They are snippets of code that accept parameters and produce output just as FileMaker’s built-in functions do. One example might be ...