On grammatical class:

boi'au
immediately convert symbolic string to number (explicit)
fa'ei
Unary mekso operator: reverse finite ordered sequence, tuple, list, string, etc.
gei'i'e
mekso unary operator: converts a string of digits which includes {pi} to the same string of digits without {pi}; if {pi} is not present in the original/input string, the output is identical