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Source for wiki CompleteSequenceCowan version 2

author

cowan

comment

Cleaned up and clarified

ipnr

198.185.18.207

name

CompleteSequenceCowan

readonly

text

The WG1 charter says "Self consistency is an important objective, which may require adding new features."  Scheme has three sequence types: lists, strings, and vectors, but the support for them is not consistent.  Lists have the most support, strings and vectors have much less, and inconsistently so.  I propose providing the following procedures, some of which are R5RS, some R6RS, some in various SRFIs, and some new:

||Type of procedure||Lists||Strings||Vectors||
||Basic constructor||`make-list` (SRFI 1)||`make-string`||`make-vector`||
||Variadic constructor||`list`||`string`||`vector`||
||Copy constructor||`copy-list` (SRFI 1)||`copy-string`||`copy-vector` (SRFI 43)||
||Basic predicate||`list?`||`string?`||`vector?`||
||Sequence length||`length`||`string-length`||`vector-length`||
||Element access?||`list-ref`||`string-ref`||`vector-ref`||
||Element mutator||`list-set!` (proposed)||`string-set!`||`vector-set!`||
||Map function||`map`||`string-map` (SRFI 13 extended)||`vector-map` (R6RS)||
||Map side effects||`for-each`||`string-for-each` (proposed)||`vector-for-each` (R6RS)||
||Convert to list||---||`string->list`||`vector->list`||
||Convert to string||`list->string`||---||`vector->string` (proposed)||
||Convert to vector||`list->vector`||`string->vector` (proposed)||---||

In summary: 33 procedures, 23 in R5RS, 2 in R6RS, 2 in SRFI 1, 1 in SRFI 43, 1 in SRFI-13 but extended to take multiple strings, 4 novel but obvious.

I further propose that the map and for-each groups should be specified to implicitly truncate all sequence arguments to the length of the shortest sequence.

time

2010-08-18 22:40:49