Formula names can contain any characters you want, including numbers, symbols and spaces. But I just found a reason not to use a space as the first character of a formula name.
A customer recently tried to modify a formula in an old report, and was prompted to log into the repository. She sent me a screen shot of the messages, which said:
enter the name of your system (Central Management Server)
Repository services are not available.
I figured that there was probably an old repository function in the formula. So I asked to see the report and went through all the formulas. There were no repository functions in any of the formulas. And yet, when I right clicked on the first formula and tried to edit it – up popped the same message. I was stumped until I noticed that the first formula name started with a space. So I switched to one of my own reports and renamed one formula so that it started with a space. When I right clicked on that formula and tried to edit it, voila! I got the same messages. I ran the same test it in versions 10, 11 and 12 and got the same result.
Apparently this is a bug in the field tree. When it takes you into the formula editor it should highlight the field that you right-clicked in the field explorer. But if the field name starts with a space it somehow tries to go to the next higher category in the list, which is the repository functions. This triggers the message.
If you get any strange behaviors in your reports that you want to share, please drop me a line.(For examples of my most popular formulas, please visit the FORMULAS page on my website.)