Is there a way (without making a plugin), to have a separate file with your custom functions in it?

When I develop, I usually make lots of little handy custom functions, and rather than copy/pasting and possible errors popping up (that and not knowing if a solution has that custom function in it) around everywhere, is there a way to have a file which filemaker points to for custom functions?

I always start off with shell copies for my solutions, but when you have quite a few on the go, and you rework a function or create a new one, it would be very nice and handy to have it available everywhere with little work ....

I like the way Clip Manager works for this. It's not that expensive, check it out here

I second the recommendation for ClipManager. Not what you were looking for, I know.

Another close-but-not-quite option is ScriptMaster by 360Works. It gives you a library of external functions written in Groovy. It's easy to add your own functions as well.

This might sound like an advertisement, but it really is amazing what you can accomplish. It's also free and doesn't require you to install any plug-ins. All you have to do is include the ScriptMaster FileMaker file in your directory and register your desired functions with an external function call when you open your solution (from what I recall). This could give you a library of functions, albeit written in Groovy, that you can access from multiple files.