Notes about results:
As per the charter, we need a module system proposal which allows sharing of code between implementations.
This is one issue where we can't default to the R5RS, since it has no module system. If we can't come to consensus, we will have to take the R6RS module system as-is.
Note the r6rs-- option is just the R6RS module system without versioning or phasing.
Student programs often want a small amount of randomness, not necessarily of very high quality. Shall we provide a simple interface to a random variables in WG1 Scheme?
RandomCowan does not allow control over the seed, so it is of such limited usefulness as to not be worth including. The API defined by SRFI 27 does allow control of the seed, and makes random sources first class, both of which are good ideas. However, the API is awkward, especially random-source-state-ref and random-source-state-set!. I'd like to see WG2 do a survey of existing implementations and find something better than both of these proposals.
R6RS provided a detailed exception system with support for raising and catching exceptions, using a hierarchy of exception types.
Do we use this, or parts of it, or a new exception system?
While the R6RS exception system is not perfect, I'm happy with it. In WG1, it belongs in a module, not in the core.
If we don't agree to use the R6RS system, then I'd rather see WG2 refine it instead of including ExceptionHandlingCowan in WG1, since the ExceptionHandlingCowan proposal doesn't explain the rationale for its deviations from R6RS. I've studied the mailing list archive and can't find a convincing argument for ExceptionHandlingCowan, either, so I'm sticking with R6RS or, as a fallback position, WG2.
The largest flaw I see with the R6RS condition system is that its condition taxonomy is too coarse and focused on operating-system issues. Compare it with the taxonomy of Gambit or MIT Scheme, for example. (See ExceptionTaxonomies for details of the condition taxonomies of many Scheme implementations.)
Some people have proposed taking the R6RS exception system but not its condition taxonomy. If we do, I hope we'll still standardize on some taxonomy rather than none. Without a common taxonomy, it's hard to share code.
SRFI-38 standardizes the #0=(1 . #0#) shared structure notation for read/write. In the case of write, this can be expensive to compute, but otherwise the common case of the repl printing a cyclic structure results in an infinite loop.
Do we want to add support for this, as an option or separate set of procedures?
srfi-38 for separate procedures or native to require read and write to handle cyclic notation.
SRFI 38 supports this notation, but doesn't require that read and write support it, so writing doesn't have to become more expensive. Since many programs won't need this feature, it belongs in a module.
As an alternative to #7, SRFI-46 proposed allowing an optional ellipse specified as an identifier before the literals list in syntax-rules:
(syntax-rules ::: () <ellipse now represented as ::: instead of ...>)
Do we allow this?
SRFI-46 and R6RS both allow a fixed number of tail patterns following an ellipsis in a syntax-rules pattern:
(P1 ... Pk Pe <ellipsis> Pm+1 ... Pn)
R6RS further allows dotted tail patterns
(P1 ... Pk Pe <ellipsis> Pm+1 ... Pn . Px)
where Px only matches a dotted list.
Do we allow either or both of these extensions?
I don't feel strongly about this issue, but the extensions seem harmless.
R6RS introduced the concept of mantissa widths as an alternative to the R5RS #s in numbers. Do we want either or both of these?
Does the reader fold case by default, and if so how?
Yes to fold-case (R5RS) no to preserve case (R6RS), additional votes to come later from specific proposals.
R6RS provides support for #; nested sexp comments, and #| ... |# nested block comments. Do we include either or both of these?
R6RS provides procedures to explicitly convert strings back and forth between the four Unicode normalization forms.
The previous phrasing of this option was overly vague, referring to "any form of normalization." I've had to treat yes votes as undecided for lack of a better default. If you voted yes before please choose one of the following options or write in your own proposal.
Note UnicodeCowan currently provides specific normalization procedures.