Add an EVALUATE() function to interpret a string as a formula. E.g. EVALUATE("2+2") would return 4.
This function already exists in VBA and allows for building formulas using text operations.
Kenneth Barber commented
I could have used that a few days ago. I was setting up references to multiple daily files. The daily files had a pattern to their names, so I used a formula to derive the full path name. For example, ="=[C:\Data"&TEXT(A1,"yyyymmdd")&".xls]Sheet1!B1" would evaluate to =[C:\Data20160706.xls]Sheet1!B1. However, this is only the value returned by the formula. I still need that value to actually evaluate as a formula.
Also, I'm well aware that daily files are bad practice, but it wasn't me that generated them.