On 2018-02-16, at 18:45:04, Robin Vowels wrote: > From: "Paul Gilmartin" > Sent: Saturday, February 17, 2018 6:18 AM > >> On 2018-02-16, at 11:33:05, Bernd Oppolzer wrote: > >>> IMO, Niklaus Wirth ... came to this decision, >>> to allow numbers as labels only, and to force them to be declared before >>> using >>> them. > >> The prior declaration is (almost) necessary for single-pass compilation. > > No it isn't. > > XPL is a single-pass compiler, and declaration of identifiers > is not required. > I said "almost". You can keep a lookback list of addresses to be plugged when they can be resolved. At some point this becomes tantamount to a second pass, over internal text.
Does XPL have nested procedure declarations, which complicate the chore? C function prototypes, not required by K&R, embody some of the prior declaration facility. -- gil
