I was reading Crafting Interpreters about a month ago and thought of writing a fizzbuzz in the language taught in the book. The language doesn't have a mod oper

I was reading Crafting Interpreters about a month ago and thought of writing a fizzbuzz in the language taught in the book. The language doesn't have a mod operator so I wrote function for that. I tried testing it against python's mod, but it didn't match where different signs were involved. I thought operands should be treated as absolute values and the resulted be negated when two different signs are involved. Then I found that python did it differently from something like C.