diff options
Diffstat (limited to 'lib/rites/rite_ef')
| -rw-r--r-- | lib/rites/rite_ef/lectionary_ef.ml | 25 | ||||
| -rw-r--r-- | lib/rites/rite_ef/lectionary_ef.mli | 7 |
2 files changed, 23 insertions, 9 deletions
diff --git a/lib/rites/rite_ef/lectionary_ef.ml b/lib/rites/rite_ef/lectionary_ef.ml index 02c3c64..37ec1d8 100644 --- a/lib/rites/rite_ef/lectionary_ef.ml +++ b/lib/rites/rite_ef/lectionary_ef.ml @@ -49,12 +49,25 @@ let readings ~lectionary ~observed ~temporal ~date ~temporal_at = records the ferial-Mass selection rule itself as unconfirmed against the primary source. - Termination: guarded on weekday. A Sunday reaching this branch - would compute [days_since_sunday Sun = 0] and look up ITSELF, - looping forever -- every other step in the chain consults data - (a lectionary lookup), this is the only one that consults - another date, so this guard is the whole chain's termination - argument, not merely a special case. + Guarded on weekday, but NOT because a Sunday reaching this + branch would loop (fix round 1, coordinator review: the + original comment here claimed exactly that, and it was wrong). + [readings] is not recursive -- step 3's fallback is one flat + [Lectionary.find], never a re-entrant call into [readings] -- + so without the guard, [days_since_sunday Sun = 0] would just + repeat the SAME [Lectionary.find] step 2 already ran and + already got [None] from (same pure inputs, same date), and + return [] once, normally. The chain as a whole terminates + because every step either consults data (a lookup) or, here, + a strictly EARLIER date via [temporal_at] -- no step ever calls + back into [readings] itself, so there is no recursion anywhere + in this function for a cycle to form in the first place. The + real reason for the guard is simpler: a Sunday has no + PRECEDING Sunday to resume -- consulting itself would be + meaningless (it would re-ask the question step 2 just + answered), not dangerous, so the guard exists to make that + intent explicit rather than to prevent a runaway loop that was + never actually possible. The preceding Sunday's TEMPORAL slug, never its observed one: the rubric is the preceding Sunday's Mass even in a year when a diff --git a/lib/rites/rite_ef/lectionary_ef.mli b/lib/rites/rite_ef/lectionary_ef.mli index 159fd57..e54a0b1 100644 --- a/lib/rites/rite_ef/lectionary_ef.mli +++ b/lib/rites/rite_ef/lectionary_ef.mli @@ -23,9 +23,10 @@ open Colitur_kernel Steps 1-3 (Tasks 4-5): the observed celebration's own proper, else the day's own temporal slug in the lectionary, else -- for a weekday whose own slug has no entry -- the preceding Sunday's temporal slug (never its - observed one; a Sunday guards against consulting itself and looping, - see [readings]'s own implementation comment). A day matching none of the - three gets [] for now -- the Commons (Task 6) are not built here. *) + observed one; a Sunday is guarded out because it has no PRECEDING Sunday + to resume, not because consulting itself would loop -- [readings] is not + recursive, see its own implementation comment). A day matching none of + the three gets [] for now -- the Commons (Task 6) are not built here. *) val readings : lectionary:Lectionary.t -> observed:Vocab_ef.rank Celebration.t -> |