(timeout budget node) bounds a node deterministically: nodes opt in via (tick),
budget ticks are allowed, the next raises flow-timeout. No scheduler/clock in pure
SX so the budget is a step count, not wall-clock. Budgets nest and are per-run.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
(retry n node) re-runs up to n attempts on a raised exception; the last attempt's
exception propagates. Explicit (fail ...) values are NOT retried — they pass through.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
(try-catch node handler) runs node; on a raised exception calls (handler error)
with the reified error via Scheme guard, returns the handler value.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Explicit (fail reason) values flow downstream as data and are inspected with
failed?/fail-reason — distinct from raised exceptions (retry/try-catch territory).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Phase 2 control flow. (branch pred then else) selects then/else node by running
pred on the threaded input; named 'branch' since 'cond' is a Scheme special form.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
