scheme1 R7RS TODO

Lists the R7RS items we intend to add, the items we explicitly aren't adding, and rough implementation notes.

Interpreter changes

Reader

• #(...) vector literals. Required by full vector support.

Runtime types

• Vector type. New heap header (HDR.VEC?), inline length + slot array. Tag stays HEAP.
• Multiple-values protocol. Internal MV vector (or stack convention) returned from values. Single-value contexts that receive ≠1 values are an error.

Special forms / form fixes

• let-values, let*-values, define-values. Depend on the MV protocol.
• Flat (one-level) quasiquote. (quasiquote ...), (unquote x), (unquote-splicing xs) evaluated at the single template depth. Nested quasiquote is unsupported. Works on lists today; extend to vectors when those land.

New primitives

These can't be expressed in Scheme; they need new entries in prim_table (or new syscall wrappers).

• Vector core: vector?, make-vector, vector-length, vector-ref, vector-set!.
• Multi-values: values, call-with-values.

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Prelude additions (prelude.scm)

These are blocked on the new primitives above; once those land the prelude wrappers are straightforward.

Vectors (§6.8) — over the new vector primitives

• Constructor: vector (variadic).
• List/string conversion: vector->list, list->vector, vector->string, string->vector.
• Bulk: vector-copy, vector-copy!, vector-append, vector-fill!.
• Higher-order: vector-map, vector-for-each.

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Permanent deviations (won't add)

These are deliberate omissions — document them in user-facing notes rather than tracking them as TODOs.

Out of scope:

• §6.2 numerics — keep fixnum.
• §4.3 macros / define-syntax / syntax-rules / let-syntax / letrec-syntax.
• §5.6 libraries / define-library / import / export / cond-expand.

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Types

• Distinct char type (chars are fixnum bytes).
• Distinct R7RS port type (we have a prelude port record over fds).
• promise, parameter, continuation, error-object, environment.

Forms

• Internal define — interpreter raises an explicit error; users must use letrec.
• delay, delay-force, force, make-promise, promise?.
• make-parameter, parameterize.
• guard as an exception form (the guard keyword is reserved for pmatch sub-clauses only).
• dynamic-wind.
• include, include-ci. (Source concatenation is shell-side.)
• Nested quasiquote.
• Block comments #| ... |# and datum comments #;.

Procedures

• utf8->string, string->utf8.
• All exception procs: raise, raise-continuable, with-exception-handler, error-object?, error-object-message, error-object-irritants, read-error?, file-error?. (error itself stays as scheme1's flush-and-exit.)
• call-with-current-continuation, call/cc.
• eval, environment, scheme-report-environment, null-environment, interaction-environment.
• The entire R7RS port surface (§6.13): call-with-port, current-input-port, current-output-port, current-error-port, input-port? / output-port? / textual-port? / binary-port? / port? / input-port-open? / output-port-open?, with-input-from-file, with-output-to-file, open-input-file / -binary- / open-output-file / -binary-, close-port / close-input-port / close-output-port, string ports (open-input-string, open-output-string, get-output-string, open-input-bytevector, open-output-bytevector, get-output-bytevector), reader/writer procs (read, read-char, peek-char, read-line, read-string, read-u8, peek-u8, u8-ready?, char-ready?, read-bytevector, read-bytevector!, write, write-shared, write-simple, write-char, write-string, write-u8, write-bytevector, flush-output-port, newline).
• load.
• current-second, current-jiffy, jiffies-per-second.
• features, emergency-exit.
• char-ci=? / char-ci<? / char-ci>? / char-ci<=? / char-ci>=? (derive from char-foldcase if needed).