[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

*To*: <srfi-43@xxxxxxxxxxxxxxxxx>*Subject*: VECTOR-UNFOLD and VECTOR-TABULATE*From*: <campbell@xxxxxxxxxxxxxxxxxx>*Date*: Thu, 19 Feb 2004 16:05:11 -0800 (PST)*Delivered-to*: srfi-43@xxxxxxxxxxxxxxxxx*Importance*: Normal

It occurred to me earlier today that VECTOR-UNFOLD is _not_ an inherently silly operation; it's just a VECTOR-UNFOLD that does not produce a fixed-size vector that's silly. Indeed, if the size of the resulting vector is fixed at the time VECTOR-UNFOLD is applied, it is VECTOR-TABULATE that is a silly operation, as it is trivially written in terms of VECTOR-UNFOLD, but VECTOR-UNFOLD is much more general. So I'd like to flush VECTOR-TABULATE in favour of VECTOR-UNFOLD: (VECTOR-UNFOLD <f> <length> <initial-seed> ...) -> [seed ...] (F <integer> <seed> ...) -> [new-seed ...] The fundamental vector constructor. Create a vector whose length is LENGTH and iterate across each index I between 0 and LENGTH, applying F to I and the current seeds, initializing the Ith slot in the new vector to the first value that F returned and continuing on with the seeds becoming the other values that F returned. VECTOR-TABULATE is just VECTOR-UNFOLD but with no seeds. While I'm at it, I'd like to add VECTOR-UNFOLD-RIGHT again. Objections?

**Follow-Ups**:**Re: VECTOR-UNFOLD and VECTOR-TABULATE***From:*campbell

- Prev by Date:
**Updates to near finalization (finally!)** - Next by Date:
**re: Updates to near finalization (finally!)** - Previous by thread:
**re: Updates to near finalization (finally!)** - Next by thread:
**Re: VECTOR-UNFOLD and VECTOR-TABULATE** - Index(es):