Easter and its Easter-relative movable feasts for a year: $ colitur easter 2026 easter 2026-04-05 ash-wednesday 2026-02-18 palm-sunday 2026-03-29 ascension 2026-05-14 pentecost 2026-05-24 corpus-christi 2026-06-04 A year outside the supported domain is rejected (exit 2): $ colitur easter 1000 colitur: year 1000 out of range 1583..9999 [2] No/garbage arguments give a usage error (exit 2): $ colitur colitur: usage: colitur easter | colitur temporal | colitur day | colitur readings (try: colitur --help) [2] The EF temporal cycle for a year, one line per day: $ colitur temporal 2026 | head -3 2026-01-01 thursday christmastide - ef-circumcision class-1 white 2026-01-02 friday christmastide - ef-christmas-1-friday class-4 white 2026-01-03 saturday christmastide - ef-christmas-1-saturday class-4 white $ colitur temporal 2026 | wc -l 365 $ colitur temporal 2026 | grep -c '^2026-04-05 ' 1 $ colitur temporal 2026 | grep '^2026-04-05 ' 2026-04-05 sunday paschaltide 1 ef-easter-sunday class-1 white A year outside the supported domain is rejected (exit 2): $ colitur temporal 1000 colitur: year 1000 out of range 1583..9999 [2] The resolved EF calendar for a year (Task 11) -- temporal AND sanctoral, occurrence and transfers applied: one line per civil-year day, "YYYY-MM-DD weekday season week slug rank colour [+commemoration-slug]...". $ colitur day 2026 | wc -l 365 Easter is the observed day exactly once, and carries no commemoration (an impeded I class day admits at most one PRIVILEGED commemoration, RG 111, and nothing outranks Easter to be impeded by it in the first place): $ colitur day 2026 | grep -c '^2026-04-05 ' 1 $ colitur day 2026 | grep '^2026-04-05 ' 2026-04-05 sunday paschaltide 1 ef-easter-sunday class-1 white Ash Wednesday: I class (RG 91 entry 7), violet, no numbered week (it falls 4 days before Lent I's own origin -- rite_ef/temporal_ef.ml's [week]): $ colitur day 2026 | grep '^2026-02-18 ' 2026-02-18 wednesday lent - ef-ash-wednesday class-1 violet Christmas: I class, white (RG 91 entry 1): $ colitur day 2026 | grep '^2026-12-25 ' 2026-12-25 friday christmastide - ef-nativity class-1 white All Souls (2 Nov, RG 91 entry 8) end to end: 2 Nov 2025 is a Sunday (verified independently -- 1 Jan 2025 is a Wednesday, day-of-year 306, (3+305) mod 7 = 0 = Sunday), so entry 8 yields to it (still an ordinary II-class Sunday, "sunday" in season time-after-pentecost, colour green -- the week number itself is not re-asserted here, already covered by test_temporal_ef.ml); RG 95 then transfers All Souls (I class, not a Sunday, not a vigil) and RG 96 places it on 3 Nov, the next day that is not I or II class: $ colitur day 2025 | grep -c 'commemoration-of-all-souls' 1 $ colitur day 2025 | grep '^2025-11-02 ' | sed -E 's/ [0-9]+ ef-time-after-pentecost-sunday-[0-9]+ / ef-time-after-pentecost-sunday- /' 2025-11-02 sunday time-after-pentecost ef-time-after-pentecost-sunday- class-2 green $ colitur day 2025 | grep '^2025-11-03 ' 2025-11-03 monday time-after-pentecost 21 commemoration-of-all-souls class-1 black (week 21: Pentecost 2025 is 8 June (colitur easter 2025); 8 Jun - 3 Nov is 148 days, floor_div(148, 7) = 21 -- rite_ef/temporal_ef.ml's own [week] formula, hand-verified before promoting this line, not merely printed and trusted.) All Souls observed directly on 2 Nov in a year where it does not fall on a Sunday: 2 Nov 2026 is a Monday (1 Jan 2026 is a Thursday, same day-of-year 306 offset, (4+305) mod 7 = 1 = Monday): $ colitur day 2026 | grep -c 'commemoration-of-all-souls' 1 $ colitur day 2026 | grep '^2026-11-02 ' 2026-11-02 monday time-after-pentecost 23 commemoration-of-all-souls class-1 black (week 23: Pentecost 2026 is 24 May (colitur easter 2026); 24 May - 2 Nov is 162 days, floor_div(162, 7) = 23 -- same formula, same independent check.) RG 96's Annunciation exception (25 March) is CONDITIONAL, not unconditional -- fix round 1, coordinator review, register corrected 2026-08-12. In 2057, 25 March is Lent III Sunday (I class, impedes it); 26 March is an ordinary Lent feria (III class, well before Easter, 22 April 2057), so the GENERAL RG 96 target -- not the Monday after Low Sunday -- is what governs, since the general walk never crosses Easter. Before this fix the unconditional reading sent it to 30 April (Easter + 8) instead: $ colitur day 2057 | grep '^2057-03-26 ' 2057-03-26 monday lent 3 annunciation-of-the-blessed-virgin-mary class-1 white +ef-lent-3-monday $ colitur day 2057 | grep -c 'annunciation-of-the-blessed-virgin-mary' 1 A year outside the supported domain is rejected (exit 2): $ colitur day 1000 colitur: year 1000 out of range 1583..9999 [2] The reading citations for a year, one line per day: date, the observed day's slug, then the Epistle and the Gospel, " | "-delimited. A SEPARATE command rather than extra columns on `colitur day`, for a mechanical reason: a citation contains spaces and commas ("Ezech 34:11-16", "Ecclus 51:1-8, 12"), while a `day` row is space-separated with a variable-length "+slug" commemoration tail, so appending them there would leave the row unsplittable by field number. `day`'s own format is therefore byte-identical to what it was before readings existed -- asserted directly, below. $ colitur readings 2026 | head -3 2026-01-01 ef-circumcision | Titus 2:11-15 | Luke 2:21 2026-01-02 ef-christmas-1-friday | Titus 2:11-15 | Luke 2:21 2026-01-03 ef-christmas-1-saturday | Gal 4:1-7 | Luke 2:33-40 $ colitur readings 2026 | wc -l 365 2 January reads the Circumcision's own Mass, not its own: the Missal's Mass-propers rubric printed under the Sanctissimi Nominis Iesu heading -- "Diebus ferialibus a 2 ad 5 ianuarii Missa dicitur ut die 1 ianuarii, cum Gloria et praefatione de Nativitate, sine Credo et Communicantes proprio" (docs/research/scan1.txt:6523-6526, corroborated scan2.txt:7216). Note this is NOT RG 17(a), which fixes only WHEN the Holy Name is kept; the two are different rules sharing a date window. Hence the identical citation on the 1st and the 2nd above, which is correct and not a duplicated row. One line per step of the reading-resolution chain, the same four cases test_golden.ml pins against the photographic scans (each literal there was read out of the Missal before being compared with colitur -- these assert that the CLI path agrees with the library path, nothing more): $ colitur readings 2038 | grep '^2038-03-08 ' 2038-03-08 john-of-god | Ecclus 31:8-11 | Matt 22:34-46 $ colitur readings 2026 | grep '^2026-02-23 ' 2026-02-23 ef-lent-1-monday | Ezech 34:11-16 | Matt 25:31-46 $ colitur readings 2025 | grep '^2025-12-01 ' 2025-12-01 ef-advent-1-monday | Rom 13:11-14 | Luke 21:25-33 $ colitur readings 2038 | grep '^2038-03-06 ' 2038-03-06 sts-felicitas-perpetua | Ecclus 51:1-8, 12 | Matt 13:44-52 The Advent line above is the ferial resumption (chain step 3) and is the one worth reading twice: 1 December 2025 is the Monday after Advent I, and Advent's ferias -- unlike Lent's -- have no Mass of their own, so the citation shown IS Advent I Sunday's ("ad Romanos. Rom. 13, 11-14" / "dum Lucam. Luc. 21, 25-33", scan1.txt:4878 + 4912). A regression that stopped walking back would change this line and nothing else. Every day of the year carries both parts -- no "-" anywhere. This is the CLI view of the invariant Validate asserts over the whole 1583..9999 domain ("citations" / "citations-unresolved"), so it is a spot-check of one year rather than the guarantee itself: $ colitur readings 2026 | grep -c ' | - \| | -$' 0 [1] `colitur day`'s own format is unaffected by any of the above: $ colitur day 2026 | head -1 2026-01-01 thursday christmastide - ef-circumcision class-1 white A year outside the supported domain is rejected (exit 2): $ colitur readings 1000 colitur: year 1000 out of range 1583..9999 [2] An explicit COLITUR_DATA_DIR that does not hold the data is an error (exit 2), never a silent fall-back to some other copy. A packager or operator who names a directory has stated an intent; quietly calendaring off a different one because theirs was wrong is the silent substitution this project refuses everywhere else. The first version of this resolution DID fall through, and a deliberately bogus value produced a full, plausible, entirely un-flagged year: $ COLITUR_DATA_DIR=/nonexistent/xyz colitur readings 2026 colitur: COLITUR_DATA_DIR is set to /nonexistent/xyz, which contains no sanctoral.sexp colitur: refusing to fall back to another data directory -- unset it, or point it at one [2] An empty or half-populated installed directory is a different case and DOES fall through to the build tree: nobody stated an intent there, and a failed or partially removed install must not shadow a working tree and then fail later with a confusing per-file error. (Exercised directly in the task, by creating _build/default/share/colitur/ef and confirming the year still resolves; not reproduced here because the cram sandbox's own exe path makes the layout awkward to stage without asserting on dune internals.) Help and usage are different things, and the difference is the Unix convention rather than a preference. Asking for help is a request that SUCCEEDED: it goes to standard output and exits 0, so it can be piped into a pager or grepped. Being invoked wrongly is an error: a one-liner to standard error, exit 2, leaving stdout clean for whatever the caller was really trying to capture. $ colitur --help | head -1 colitur -- deterministic liturgical calendar engine (Roman rite, 1962) $ colitur -h | head -1 colitur -- deterministic liturgical calendar engine (Roman rite, 1962) $ colitur --help > /dev/null $ colitur -h > /dev/null Nothing on stderr, and exit 0 (an exit other than 0 would print a [N] line): $ colitur --help 2>&1 >/dev/null The error path is the mirror image -- nothing on stdout, exit 2: $ colitur bogus 2>/dev/null [2] Every command the help lists is a command the binary actually accepts. This is the check that catches help text drifting away from the dispatch: $ for c in easter temporal day readings; do colitur $c 2026 > /dev/null || echo "$c FAILED"; done --version prints the version alone, to standard output, exit 0. Deliberately not embedded in the help text above: this pin would then have to be edited every release, for no gain. The Makefile's release target asserts the built binary reports the version it just wrote, so the two cannot drift. $ colitur --version 0.1.0 $ colitur -V 0.1.0 Agreement with the package metadata (dune-project's own (version ...), which generates colitur.opam) is NOT asserted here: the cram sandbox has no source tree to read dune-project from. It is asserted in the Makefile's release target instead, which rewrites both and then requires the freshly built binary to report the version it just wrote -- the point in time where a drift between the two could actually be introduced.