Alex Shinn is the only active member of WG1 who is also an implementer. Here is a preliminary list of things he has to implement as part of R7RS-compliance in Chibi Scheme that he voted against. However, he has said that he sometimes votes for R5RS choices in order to provide a conservative voice.
- the call-cc alias
- _ in syntax-rules
- SRFI 46
- dotted-tail patterns in syntax rules
- block comments
- char folding
- case-lambda
- => in case
- case-folding dircctives
- string-set! in (scheme base)
- begin rather than body as a library declaration
- requiring equal? to return #t if eqv? does
- possibly something about #48, but I don't understand what
- new integer division operators
- procedures not having locations
- let-values and let*-values
- allowing cond-expand, include, and include-ci at top level
- error-object?, error-object-message, and error-object-irritants
- everything to do with multiple values
- more than two arguments for char and string comparisons
- making it an error for a procedure mapped by map and friends to return more than once
- #u8 syntax for bytevectors rather than #vu8
- vertical bars around symbols
- close-port
- make-promise
- (scheme ...) instead of (r7rs ...)
- UAX 29 based string case conversion
- fundamental I/O in (scheme base)
- interaction-environment in (scheme repl)
- record types in (scheme base)
- semicolon-based rather than brace-based escape sequences
- R6RS rather than dotted-ratio syntax for non-rational reals
- -nan.0
- make-promise
- start and end arguments in various procedures
- string-copy! and vector-copy!
- numeric syntax in programs must agree with string->number and read
- support for undesirable characters and arbitrary numbers in library names
- same-bits explanation of eqv? on IEEE inexacts
- location-free procedures
- complex numbers with +nan.0 portions
- predicates for R5RS signaled conditions
- emergency-exit
- type-check rule for auto-forcing
- support for bare CR as newline
- digit-value
- singular library names
- multiple imports in program files