Well, to summarize:

- You make indices and values and for-loops over them, instead of doing the c-version of foreach, NEW_MAPPING_LOOP.

- You iterate over all characters in each string once to check for illegal characters and once more to replace them. The idea is that the check is more lightwieght than calling f_replace...

- You push_text (instead of push_constant_text or pushing premade pike_string:s) and then aggregate them (instead of ref_pushing premade arrays)

- You call f_replace with constant replace arrays instead of calling a premade replace object.