feat: output, rendering and publishing

Gives colitur a publishable exit. Until now its only output was terminal
rows; it can now print an ordo booklet and a wall calendar, publish an
iCalendar feed people subscribe to, and serve a static JSON/XML API.

  lib/render   escaping (six flavours + RFC 5545 folding), a deliberately
               logic-less template engine, the view model, and five
               emitters (CSV, JSON, XML, iCalendar, S-expression)
  CLI          emit, table, render, publish -- all accepting --overlay
  templates    ordo booklet in six flavours, wall grid in three
  schema       day-v1.json and colitur-v1.xsd, the published contract
  man          colitur-templates.5, plus colitur.1 updates

The view model is why the engine can stay logic-less: a month grid needs
leading blank cells, week bucketing and an in-month test, and a
logic-less template can compute none of it. Shaping the data in OCaml
keeps the engine safe for untrusted templates and makes the grid
trivial.

Formats split by whether correctness is mechanical. Presentation goes
through templates; iCalendar and XML get dedicated emitters, because
folding, exclusive DTEND, stable UIDs and schema fidelity are rules a
template cannot enforce and each fails silently in a subscriber's
client rather than loudly at generation.

publish is deterministic and non-destructive: two runs produce a
byte-identical tree, and --prune removes only files a previous run
created, refusing any manifest entry that escapes the output directory.

No new dependencies. The kernel and rite modules are untouched, and
colitur day and colitur readings remain byte-identical.

1 files changed, 788 insertions, 0 deletions

diff --git a/man/colitur-templates.5 b/man/colitur-templates.5
new file mode 100644
index 0000000..2f42d68
--- /dev/null
+++ b/man/colitur-templates.5
@@ -0,0 +1,788 @@
+.TH COLITUR\-TEMPLATES 5 "2026" "colitur" "File Formats"
+.SH NAME
+colitur\-templates \- template format for colitur(1)'s table, render and publish
+.SH SYNOPSIS
+.I booklet.tex
+.br
+.I calendar.html
+.br
+.I feed.ics
+.SH DESCRIPTION
+A
+.B colitur
+template is the file named by
+.BR "colitur table" 's
+and
+.BR "colitur render" 's
+.B \-\-template
+flag (and used internally by
+.BR "colitur publish" ).
+It is a deliberately logic\-less, Mustache\-family format: the file is
+.I data,
+never a program. There are exactly four constructs \(em variable
+interpolation, a section, an inverted section, and a comment \(em and nothing
+else.
+.PP
+.B There are no partials, no lambdas, no arithmetic, no expression
+.B evaluation, and no "raw" or triple\-brace form that could opt out of
+.B escaping.
+A template cannot include another file, cannot compute anything, and cannot
+choose to skip the escaping its own flavour applies. Everything a rendered
+document needs \(em conditionals on emptiness, iteration over days or weeks,
+formatting \(em is expressed with the four constructs below over the fields
+.B VIEW MODEL
+describes; nothing else is available, and nothing else will be added by
+supplying cleverer template syntax \(em that is what the escaping and
+scope rules exist to prevent.
+.SH SYNTAX
+.TP
+.BI "{{" name "}}"
+Interpolates the value at
+.I name,
+a dot\-separated path resolved against the current scope (see
+.B SCOPE AND LOOKUP
+below). A string value is escaped per the active flavour and inserted; a
+boolean
+.B true
+renders as the literal text
+.RB \(lq true \(rq,
+.B false
+renders as nothing; a list or an object value used as a plain variable also
+renders as nothing \(em only a section can iterate one. A path that resolves
+to nothing renders as nothing, silently: this is the one deliberate silence
+in the engine, so a template survives a day that does not carry every
+optional field (an empty
+.I week
+on a day the rite does not number, an empty
+.I first
+or
+.I gospel
+citation, and so on).
+.TP
+.BI "{{#" name "}}...{{/" name "}}"
+A section. If
+.I name
+resolves to a
+.B list,
+the body is rendered once per item, with each item pushed onto the scope
+stack (see below). If it resolves to a truthy non\-list value (a non\-empty
+string, or an object), the body is rendered once, with that value pushed onto
+the stack. If it resolves to nothing, or to a falsy value (an empty string,
+.BR false ,
+or an empty list), the body is skipped entirely.
+.TP
+.BI "{{^" name "}}...{{/" name "}}"
+An inverted section: the mirror image of
+.BR # .
+The body renders \(em exactly once, without pushing anything new onto the
+scope \(em only when
+.I name
+resolves to nothing, or to a falsy value. This is how a template supplies a
+fallback for an optional or absent field.
+.TP
+.BI "{{!" " text " "}}"
+A comment. Everything between
+.B {{!
+and the closing
+.B }}
+is discarded; nothing is written to the rendered output. See
+.B HOST\-LANGUAGE COMMENTS
+below before relying on this for documentation inside a template that also
+has its own comment syntax.
+.PP
+A section and its inverted counterpart, and a section and its close tag, must
+name the identical path \(em
+.BR {{#days}} " ... " {{/months}}
+is a parse error, not a silently mismatched close. An empty path
+(
+.BR {{.}} ", " {{#}} ", " {{^}} ", " {{/}}
+) is also a parse error: there is no "current context" concept for a bare dot
+to mean, so nothing is guessed on a template's behalf.
+.PP
+A malformed template \(em an unterminated
+.BR {{ ,
+a section left unclosed, a close tag with no matching open \(em is reported
+with the parser's own reason and exits 2. A template is user input, exactly
+like an
+.BR colitur\-overlay (5)
+file, and is never allowed to crash the program that reads it.
+.SH SCOPE AND LOOKUP
+.B This section documents a real hazard, not a theoretical one \(em it has
+.B produced wrong output during this program's own development.
+.PP
+Scope is a stack. Rendering starts with the whole view (the year) as the one
+entry on the stack; each
+.B {{#section}}
+pushes the value it iterates or opens onto the stack for the duration of its
+body, and pops it again at
+.BR {{/section}} .
+A lookup for
+.I name
+is tried against the
+.I innermost
+(most recently pushed) entry first. If
+.I name
+is not found there, the lookup falls back to the
+.I next
+entry outward, and so on to the outermost (the year itself). This fallback is
+deliberate and necessary \(em without it, a cell deep inside
+.B {{#months}}{{#weeks}}{{#days}}
+could never reach
+.BR {{year}} ,
+which lives only on the outermost object.
+.PP
+.B The hazard: a DOTTED PATH that resolves only PART WAY inward falls back
+.B WHOLESALE to an outer scope of the SAME NAME.
+A bare key inside the immediately enclosing section is not at risk this way
+\(em it either resolves right there or fails outright (see
+.B num
+below); it is specifically a dotted path, one step of which is missing from
+the inner object, that abandons the whole path and restarts the lookup one
+level out. Falling back outward means a name that exists at
+.I both
+levels never fails and never warns \(em it just silently resolves to the
+.I outer
+one, because the inner object's own absence of that key is indistinguishable
+from "look further out" and "this key does not apply here". Two collisions
+are known to exist in the shipped view model:
+.TP
+.B name
+Both a
+.B month
+and a
+.B day
+carry a
+.I name
+field (each an object keyed by language, e.g.
+.BR la " and " en ).
+Written naively, when
+.B {{#days}}
+is nested inside
+.BR {{#months}} ,
+a bare
+.B {{name.la}}
+does
+.I not
+resolve to the day's own Latin name. It resolves to the
+.I enclosing month's
+Latin name, because the day's own
+.I name
+object either has no
+.B la
+key (an unnamed day) or the dotted path fails partway and the WHOLE path
+falls back to the outer scope, which does have one. This is not a corner
+case: on an ordinary month, most days carry no Latin name at all (only named
+sanctoral days do), so the naive form renders the
+.I month's
+name on nearly every day \(em in a per\-month booklet, dozens of wrong
+lines; in a month grid (whose
+.B {{#weeks}}
+is itself only ever reachable through
+.BR {{#months}} ,
+since
+.I weeks
+is a field of
+.IR month ,
+never a top\-level list) EVERY cell reads the month's own name.
+.PP
+.B The collision needs a month actually on the scope stack to fire.
+Iterating the TOP\-LEVEL, flat
+.B days
+list directly (
+.B {{#days}}...{{/days}}
+at the outermost level, never passing through
+.B {{#months}}
+first) puts no month object anywhere on the stack, so the naive form does
+.I not
+silently substitute the wrong answer there \(em it silently resolves to
+nothing, exactly as any other absent key would, because there is no
+outer scope left to climb to. This is precisely what makes the hazard easy
+to miss: an author who tries the naive form against the flat list first
+sees the unnamed days come out empty, reasonably concludes the form is
+safe, and then hits the real collision the moment the identical fields are
+read from inside
+.BR {{#months}} ,
+which is what every shipped template that produces a grid or a per\-month
+booklet actually does.
+.TP
+.B num
+Both a
+.B month
+and a
+.B week
+carry a
+.I num
+field. Inside
+.BR {{#weeks}} ,
+a bare
+.B {{num}}
+is the week's own number, correctly \(em but only because nothing between
+the week and the day currently redefines it. A template that reaches
+.I num
+from any scope where the immediately enclosing section does not itself
+carry it will silently climb to whichever ancestor does, and that may not be
+the one the author meant.
+.PP
+.B The safe idiom.
+Push the object you actually want onto the scope stack yourself, with a
+.B {{#name}}
+section, before reading its fields \(em then a bare field inside that
+section can only resolve against the object you just pushed, or fail
+outright and fall through to an inverted fallback you write explicitly:
+.RS
+.nf
+
+{{#name}}{{la}}{{^la}}{{slug}}{{/la}}{{/name}}
+.fi
+.RE
+This opens the day's own
+.I name
+object (never the month's \(em a
+.B {{#section}}
+always resolves its OWN path from the point it appears, which for
+.B {{#name}}
+written inside
+.B {{#days}}
+is the day's
+.IR name ,
+shadowing the month's identically\-named field exactly as intended), reads
+.B la
+from it, and falls back to the day's own
+.B slug
+only when
+.B la
+is genuinely absent from
+.I that
+object \(em never when it is merely absent from an ancestor. Every shipped
+template that prints a day's name uses exactly this idiom; none uses the
+bare dotted form.
+.SH HOST\-LANGUAGE COMMENTS
+.B The engine has no awareness of the target language's own comment syntax.
+A
+.B {{...}}
+tag inside a LaTeX
+.BR % ,
+a groff
+.BR .\e" ,
+or an HTML
+.B <!\-\- \-\->
+comment is still lexed and rendered exactly as if it were live template
+markup \(em the engine sees only its own
+.B {{
+/
+.B }}
+delimiters, never the host format's comment sigils, because a template is
+rendered as one flat character stream, not parsed as LaTeX, groff or HTML
+first. This broke a shipped template during development: an explanatory
+.B {{example}}
+written inside a LaTeX
+.B %
+comment, meant purely as documentation for a future reader, was parsed as a
+real variable reference.
+.PP
+Write in\-template documentation without any
+.B {{
+or
+.B }}
+characters in it, in whatever host\-comment syntax the target format uses.
+Use
+.B {{!comment}}
+only where the surrounding host format has no comment syntax of its own that
+would otherwise be preferable (its own body is safe \(em text between
+.B {{!
+and
+.B }}
+is discarded unparsed, so a stray
+.B {{
+inside a
+.B {{!...}}
+comment is not itself a hazard \(em but the comment's own delimiters are
+still ordinary
+.B {{
+/
+.B }}
+tokens, so they compete with the host format's own comment syntax for the
+same file exactly as any other tag would).
+.SH FLAVOURS
+.B \-\-flavour
+selects how an interpolated
+.I value
+is escaped before being written. It never touches the template's own literal
+markup (the LaTeX, groff, HTML, XML or ICS surrounding a
+.BR {{tag}} ),
+which is the template author's and is trusted exactly as written. One of six:
+.TP
+.B latex
+.BR \e " \(-> " \etextbackslash{} ,
+.BR { " \(-> " \e{ ,
+.BR } " \(-> " \e} ,
+.BR $ " \(-> " \e$ ,
+.BR & " \(-> " \e& ,
+.BR # " \(-> " \e# ,
+.BR _ " \(-> " \e_ ,
+.BR % " \(-> " \e% ,
+.BR ^ " \(-> " \etextasciicircum{} ,
+.BR ~ " \(-> " \etextasciitilde{} .
+Every LaTeX special character is covered; nothing else is touched.
+.TP
+.B groff
+A backslash is escaped to
+.BR \ee ,
+because a bare backslash starts a groff escape. If the ESCAPED string then
+begins with
+.B .
+or
+.BR ' ,
+the zero\-width non\-printing character
+.B \e&
+is prefixed \(em a
+.B .
+or
+.B '
+in column one would otherwise start a request rather than print literally.
+.TP
+.B html
+(also used for the
+.B xml
+flavour, identically)
+.BR & " \(-> " &amp; ,
+.BR < " \(-> " &lt; ,
+.BR > " \(-> " &gt; ,
+.BR \(dq " \(-> " &quot; ,
+.BR ' " \(-> " &#39; .
+.TP
+.B xml
+Identical to
+.B html
+above.
+.TP
+.B ics
+Per RFC 5545: a backslash doubles, a semicolon and a comma are each
+backslash\-escaped, a newline becomes the two\-character sequence
+.BR \en ,
+and a carriage return is dropped outright (never doubled or passed through).
+Line folding at 75 octets, on a UTF\-8 character boundary, is applied
+separately to the whole rendered line \(em it is not part of value escaping
+and is not something a template can see or control.
+.TP
+.B none
+Escapes nothing at all: the value is inserted byte\-for\-byte. See
+.B LIMITATIONS
+below \(em this is not an oversight, and it is not safe to treat as one.
+.PP
+.B \-\-flavour
+is inferred from
+.BR \-\-template 's
+own file extension when the flag is omitted:
+.RS
+.nf
+
+.I .tex              \(-> latex
+.I .ms .mom .me      \(-> groff
+.I .html .htm        \(-> html
+.I .xml              \(-> xml
+.I .ics              \(-> ics
+.I .md .adoc .txt    \(-> none
+.fi
+.RE
+.PP
+An extension
+.B colitur
+does not recognise is a hard
+.B ERROR
+naming the six flavours above; it is
+.I never
+a silent fallback to
+.BR none .
+Guessing the flavour wrong would produce output that looks fine right up
+until the metacharacters it silently failed to escape appear in a rendered
+document.
+.SH LIMITATIONS
+.B AsciiDoc and Markdown are NOT escaped.
+The
+.B none
+flavour (selected for
+.IR .md " and " .adoc ,
+as well as
+.IR .txt )
+passes every interpolated value through unchanged. This is a deliberate
+choice, not a gap: unlike LaTeX, groff, HTML, XML or ICS, AsciiDoc and
+Markdown have no fixed, small metacharacter set that could be escaped
+mechanically \(em their own metacharacters are context\-dependent (a
+.B *
+means something different at the start of a line than in the middle of a
+word), and escaping them here, generically, would produce
+.I worse
+output than leaving values alone in the ordinary case.
+.PP
+The consequence is real and is stated here plainly rather than left for a
+reader to discover: a feast name, or any other interpolated field, containing
+.B *
+or
+.B _
+renders as Markdown/AsciiDoc emphasis in the rendered document, not as a
+literal asterisk or underscore. No shipped sanctoral name currently contains
+either character, but a
+.BR colitur\-overlay (5)
+file supplying a local celebration's own name is not validated against this
+constraint, and its author is responsible for avoiding both characters, or
+accepting the emphasis, in any name rendered through a
+.I .md
+or
+.I .adoc
+template.
+.PP
+Only the Extraordinary Form (1962) view model is documented below; see
+.BR colitur (1)
+for the rite's own scope and limitations (readings cover only the Epistle
+and Gospel; the votive Office of the Blessed Virgin Mary on Saturday does not
+yet select among its five seasonal Masses).
+.SH VIEW MODEL
+The value a template renders against is built once per
+.B colitur table
+/
+.B render
+/
+.B publish
+invocation, from the same resolved calendar
+.B colitur emit
+uses, and is shaped for two artefacts from one model: a flat booklet (the
+.B days
+list, one entry per day of the requested year) and a month grid (the
+.B months
+list, each carrying its own
+.B weeks
+list of Sunday\-started, seven\-cell rows, padded at both ends with blank
+cells so every row has exactly seven). This is the same shape published at
+.IR schema/day\-v1.json ,
+described here in prose; the JSON Schema is the machine\-checked contract and
+this page is its worked explanation.
+.SS Top level
+.TP
+.B rite
+The rite identifier, currently always the string
+.BR ef .
+.TP
+.B year
+The civil year requested, as a four\-digit string.
+.TP
+.B months
+A list of twelve
+.B month
+objects, January through December.
+.TP
+.B days
+A flat list of every day's own
+.B day
+object, in date order, for the whole requested year \(em what a booklet
+template iterates over directly, without going through
+.BR months .
+.SS month
+.TP
+.B num
+The month number, 1 through 12, as a string.
+.TP
+.B name
+An object keyed by language (currently
+.B la
+and
+.BR en ),
+each value the month's own name in that language (e.g.
+.RB \(lq Ianuarius \(rq
+/
+.RB \(lq January \(rq ).
+.TP
+.B days
+This month's own
+.B day
+objects, in date order, only the days that actually fall in this month.
+.TP
+.B weeks
+This month's
+.B day
+objects grouped into Sunday\-started rows of exactly seven, the first and
+last rows padded with blank cells (see
+.B day \(->  in_month
+below) so every row has seven entries regardless of which weekday the month
+starts or ends on.
+.SS week
+.TP
+.B num
+The week's ordinal within its month (1, 2, 3, ...), as a string. This is
+.I not
+a liturgical week number \(em see
+.B day \(-> week
+below for that.
+.TP
+.B days
+Exactly seven
+.B day
+objects, Sunday first.
+.SS day
+Every key below is always present on every day object, including a padding
+cell (see
+.BR in_month ),
+so a template never hits a missing key on a real day OR a blank grid cell \(em
+the one deliberate exception is that a padding cell's own string fields are
+all set to the empty string and its boolean and list fields to
+.B false
+/empty, which read as absent under
+.BR # / ^ / {{var}}
+exactly as a genuinely unset field would.
+.TP
+.B iso
+The date, ISO\-8601 (\c
+.IR YYYY\-MM\-DD ).
+Empty on a grid padding cell.
+.TP
+.B dom
+The day of the month, as a string (no leading zero). Empty on a padding
+cell.
+.TP
+.B dow
+The day of the week as a string digit,
+.B 0
+for Sunday through
+.B 6
+for Saturday. Present, and meaningful, even on a padding cell \(em it is how
+a grid template knows which column a blank cell belongs in.
+.TP
+.B in_month
+Boolean.
+.B false
+on a padding cell (a blank cell added so a month's first or last week has
+seven entries); a template checks this, not
+.BR iso 's
+emptiness, to decide whether to render a cell's contents.
+.TP
+.B season
+The liturgical season's own string name (e.g.
+.BR paschaltide ", " lent ).
+.TP
+.B week
+The liturgical week number within the season, as a string, or the empty
+string on a day the rite does not number (this is
+.I not
+the same field as a
+.B week
+object's own
+.BR num ,
+described above \(em see
+.B SCOPE AND LOOKUP
+for why the two identically\-named fields do not collide here: a plain
+.B day
+object has no
+.B num
+key of its own at all, only
+.BR week ,
+so there is nothing for it to shadow).
+.TP
+.B slug
+The observed celebration's stable identifier (e.g.
+.BR ef\-easter\-sunday ).
+.TP
+.B name
+An object keyed by language, the observed celebration's own name in each
+language colitur's data supplies one for. Frequently has no
+.B la
+or
+.B en
+key at all (most temporal days, most sanctoral entries in the shipped data)
+\(em see
+.B SCOPE AND LOOKUP
+above for the resulting month\-name collision and its safe idiom.
+.TP
+.B rank
+The observed celebration's class, as the kernel's own string (e.g.
+.BR class\-1 ).
+There is deliberately no separate, localized rank label: the kernel carries
+no per\-language rank names to draw one from.
+.TP
+.B colour
+The observed celebration's liturgical colour, lowercase (one of
+.BR white ", " red ", " green ", " violet ", " rose ", " black ,
+or the empty string).
+.TP
+.BR is_white ", " is_red ", " is_green ", " is_violet ", " is_rose ", " is_black
+Six booleans, exactly one true (matching
+.BR colour )
+on a real day, all false on a padding cell. Provided so a template can
+select styling (a cell background colour, a class name) with a plain
+.B {{#is_white}}
+section instead of a string comparison the engine does not offer \(em there
+is no expression evaluation, so this is the only way a template branches on
+colour at all.
+.TP
+.B subject
+Whose feast this is, lowercase (one of
+.BR lord ", " bvm ", " saint ", " temporal ).
+.TP
+.B comms
+A list of commemoration objects admitted on this day, each carrying
+.BR slug ,
+.B name
+(an object keyed by language, same shape as the day's own
+.BR name ),
+and
+.B privileged
+(boolean: true for a privileged commemoration under RG 109, which survives
+even where an ordinary one would be capped out). Empty list on a day with no
+commemorations, and always an empty list \(em never absent \(em on a padding
+cell.
+.TP
+.B transferred_in
+A list of at most one object, present when a feast impeded elsewhere was
+transferred onto THIS day (RG 96\(en98); carries the transferred
+celebration's own
+.BR slug .
+Empty list when nothing transferred in.
+.TP
+.B transferred_out
+A list of objects, one per celebration that would have fallen on this day
+but was displaced and moved to a later date; each carries
+.B slug
+and
+.B to
+(the ISO\-8601 date it was moved to). Empty on the ordinary day.
+.TP
+.B first
+The Epistle/Lesson reading citation (e.g.
+.RB \(lq "Heb 1:1\-12" \(rq ),
+never scripture text \(em a reference only. Empty string when none resolved.
+.TP
+.B gospel
+The Gospel reading citation, same shape as
+.BR first .
+.TP
+.B last
+Boolean, true on the seventh (final) cell of a grid row, false everywhere
+else including every entry of the flat
+.B days
+list. Exists because the engine offers no "unless this is the last item"
+construct, so a template that must print a separator BETWEEN cells but not
+after the last one (a table row's column rule, for instance) reads this flag
+rather than computing it: without it, a seven\-column LaTeX grid would emit
+an eighth, empty column and
+.B pdflatex
+would reject the file outright.
+.SH A WORKED MINIMAL TEMPLATE
+A plain\-text booklet, days nested inside months \(em the shape every
+shipped template actually uses, and the shape the
+.B SCOPE AND LOOKUP
+hazard needs to fire \(em using the safe name idiom from that section:
+.RS
+.nf
+
+{{rite}} {{year}}
+{{#months}}{{#days}}
+{{iso}} {{#name}}{{la}}{{^la}}{{slug}}{{/la}}{{/name}} {{colour}}{{#comms}} +{{slug}}{{/comms}}
+{{/days}}{{/months}}
+.fi
+.RE
+.PP
+Rendered (extension
+.IR .txt ,
+so flavour
+.BR none ,
+no escaping applied; the blank lines are the template's own \(em its section
+body starts and ends with a literal newline, and this engine does not trim
+one):
+.RS
+.nf
+
+.B colitur table \-\-year 2026 \-\-template minimal.txt | head \-7
+ef 2026
+
+2026\-01\-01 ef\-circumcision white
+
+2026\-01\-02 ef\-christmas\-1\-friday white
+
+2026\-01\-03 Officium sanctae Mariae in sabbato white
+.fi
+.RE
+.PP
+The second data line shows the fallback firing: 2 January carries no Latin
+.B name
+in the shipped data, so
+.B {{^la}}
+supplies
+.B {{slug}}
+instead. The third shows the non\-fallback case: 3 January
+.I does
+carry a Latin name (the votive Office of the Blessed Virgin Mary on
+Saturday), and the idiom prints it correctly.
+.PP
+Now swap only the interpolation \(em the safe idiom above becomes the
+naive, unsafe
+.B {{name.la}} ,
+nesting left exactly as it was:
+.RS
+.nf
+
+{{rite}} {{year}}
+{{#months}}{{#days}}
+{{iso}} {{name.la}} {{colour}}
+{{/days}}{{/months}}
+.fi
+.RE
+.PP
+Rendered against the identical year, same extension and flavour:
+.RS
+.nf
+
+.B colitur table \-\-year 2026 \-\-template minimal\-unsafe.txt | head \-7
+ef 2026
+
+2026\-01\-01 Ianuarius white
+
+2026\-01\-02 Ianuarius white
+
+2026\-01\-03 Officium sanctae Mariae in sabbato white
+.fi
+.RE
+.PP
+The collision fires for real on the first two lines: with a month on the
+scope stack, the day's own missing
+.B la
+key falls back all the way out to the ENCLOSING MONTH's own
+.RB \(lq Ianuarius \(rq
+rather than failing. The third line is untouched, because 3 January's own
+.I name
+object genuinely has a
+.B la
+key, so the dotted path resolves without ever needing to fall back.
+.PP
+.B This is specific to nesting, and that is the point.
+The identical naive
+.B {{name.la}}
+written against the TOP\-LEVEL, flat
+.B days
+list (no
+.B {{#months}}
+wrapping it) does
+.I not
+print
+.RB \(lq Ianuarius \(rq
+anywhere \(em there is no month on the stack to fall back to, so it prints
+nothing on an unnamed day instead, silently but not wrongly. See
+.B SCOPE AND LOOKUP
+above for why testing the naive form only against a flat list is exactly
+how this hazard goes unnoticed until a template is later nested under
+.BR {{#months}} .
+.SH SEE ALSO
+.BR colitur (1)
+for
+.BR table ", " render " and " publish ,
+and for the five
+.B emit
+formats that share this same view model.
+.PP
+.BR colitur\-overlay (5)
+for the local\-calendar file format that supplies the celebrations a
+template's
+.B name
+and
+.B slug
+fields can carry.
+.SH LICENSE
+AGPL\-3.0\-or\-later.