Phase 1 engine step 4 — R7RS compatibility primitives for the CEK evaluator.
call/cc: undelimited continuation capture with separate CallccContinuation
type (distinct from delimited shift/reset continuations). Escape semantics —
invoking k replaces the current continuation entirely.
raise/raise-continuable: proper CEK arg evaluation via raise-eval frame.
Non-continuable raise uses raise-guard frame that errors on handler return.
host-error primitive for safe unhandled exception fallback.
Multi-arity map: (map fn list1 list2 ...) zips multiple lists. Single-list
path unchanged for performance. New multi-map frame type.
cond =>: arrow clause syntax (cond (test => fn)) calls fn with test value.
New cond-arrow frame type.
R7RS do: shape-detecting dispatch — (do ((var init step) ...) (test result) body)
desugars to named let. Existing (do expr1 expr2) sequential form preserved.
integer? primitive, host-error alias. Transpiler fixes: match/case routing,
wildcard _ support, nested match arm handling.
2522/2524 OCaml tests pass (2 pre-existing scope failures from transpiler
match codegen, not related to these changes).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
giles
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