The latter is already available as digit-value in R7RS, but would be required for parser than format combinators.  The former is not; it requires either two arguments (as specified) or a single argument with a format variable.  So it's really just one procedure taking two arguments or else two arguments .  The question is whether it can already be implemented in the default SRFI 166 framework.  Not being a SRFI 166 extension programmer, I don't know the answer.

John Cowan          http://vrici.lojban.org/~cowan        xxxxxx@ccil.org
"After all, would you consider a man without honor wealthy, even if his
Dinar laid end to end would reach from here to the Temple of Toplat?"
"No, I wouldn't", the beggar replied.  "Why is that?" the Master asked.
"A Dinar doesn't go very far these days, Master.        --Kehlog Albran
Besides, the Temple of Toplat is across the street."      The Profit