deterministic OCaml engine to compute and validate liturgical calendars for multiple rites, template-driven output to year 9999 https://git.labunix.xyz/colitur.git/atom?h=main 2026-08-17T15:46:31Z 2026-08-17T15:46:31Z Lukasz Kasprzak lukas@labunix.xyz 2026-08-17T15:46:31Z urn:sha1:0a4bb4e6c3cbcafb302962d9d1e70b5a0bb554b8 The Overlay algebra has been built and tested since Plan 2, and Date_spec grew movable variants last commit, but there was still no way to hand colitur a file: bin/main.ml applied exactly one overlay, the shipped data/ef/adjustments.sexp, with the path hardcoded. This is the plumbing. --overlay is repeatable and ordered, and applies ON TOP of the shipped adjustments rather than instead of them. That ordering is the whole point: adjustments.sexp carries RG 110's own 30 June companion, the Major Litanies, St Barbara and Rogation Wednesday, and a user file that replaced it would silently drop all four while appearing merely to add a local feast. Overlay.merge is last-writer-wins, so a local calendar can still override a universal entry deliberately, by naming its slug. The dispatch needed real argument parsing. It matched Sys.argv as an exact array, which does not survive a repeatable flag -- two --overlay arguments are a different array shape from one, and each further flag would multiply the patterns again. Flags are now stripped first and the remaining words matched as command plus year. Hand-rolled, because the dependency list is frozen and this is fifteen lines. One defect found by the cram suite on the first run: the unknown-option guard rejected --help and --version, having excluded only their short forms. Refused, not ignored, on easter and temporal. Neither reads sanctoral data -- temporal deliberately runs the cycle before any layer exists -- so accepting the flag there and silently doing nothing is the failure mode this project refuses everywhere else. A file that fails to load is fatal, exactly as the shipped overlay is; a directive naming a slug that does not exist warns on stderr and the run continues. The second matters more for a user file than for ours: a typo in a diocesan calendar should say so rather than quietly do nothing. test/fixtures/overlay-example-diocesan.sexp is a worked example and is labelled as invented, not calendar data. It carries both shapes a real local calendar needs: a fixed-date patron, and a dedication on "the first Sunday of October" -- which is the case the Date_spec work existed to unlock and which lands on 4 October in 2026, 3 October in 2027, 1 October in 2028. The dedication is I class because a church's own dedication anniversary is I class in that church; at III class it lost to the II-class Sunday every year, which a first draft demonstrated correctly and uselessly. The man page gains an OVERLAYS section saying plainly that an overlay is applied, NOT validated: the five test layers assert things about the shipped calendar and none of them can vouch for a file the user supplies. This is the first feature that lets someone change what colitur computes, and that distinction should not have to be inferred.