Hi,
what do you mean by "boolean function"?
For boolean operations you can use
1. Case structure. It is located in Functions->Structures
2. Boolean functions (such as AND, OR, NOT, etc.). They are located in Functions->Boolean
3. Comparison functions (such as equal?, greater?, less?, etc.). They are located in Functions->Comparison
You have to give more info about your problem.
Good luck.
Oleg Chutko.