Extending attributes
There are two ways to give meaning: a large class hierarchy, or a few interpreted words plus an open vocabulary. koyu takes the second. Extension is adding a word, not revising a schema, and that is where connections to outside classification systems — city data, property identifiers, sensors, network data — can land.
But the openness has a shape. Being open and being trustworthy are compatible provided the boundary is declared. Without that declaration you cannot tell "not looked at" from "looked at and fine". An "all clear" in that state means nothing.
Types are free words
The second positional argument of space is the type. It is optional, and any value passes.
grid X 0 2000
grid Y 0 2000
level L1 0 h:2400 slab:150
space /L1/a wumbo X1..X2 Y1..Y2
space /out outside:1
boundary /L1/a /out✔ Consistent — 1 space / 0 boundaries
Structural consistency only — architectural validity is what koyu validate says, separatelyThe words the bundled examples reach for most are shop, corridor, shaft, room, service, unit, stair and hall, and a good many space lines write no type at all. That is de facto usage, not a ledger and not a contract.
Not one word is closed
The type position is open all the way through. Core never reads it. stair, shaft, ldk and 厨房 are all equally free words to core, and writing none at all is fine.
Two words used to be the exception. exterior and void — being outside, having no floor — were written in the type position and read structurally. And that is what made the claim on this page untrue.
✖ near.muro:line 5: The type exteriorr looks like a misspelling of exterior …That watch was put there after a measurement: one extra character in exteriorr stopped a space being outside and took the gross floor area from 16.20 m2 to 32.40 m2, with check green throughout. But refusing words one edit away is a hunch standing in for a rule, and it could not even be widened to two — two edits from void reaches road and wood, words a person may legitimately write. When the reach of a protection is set by what a heuristic happens to allow, it is not a design.
The two words moved into the declaration
space /out name:南側道路 road:6000 outside:1
space /L2/hole X1..X2 Y1..Y2 name:吹抜け void:1outside and void became keys in the ledger. The same protection now applies as a rule: outsid:1 is an ATT03 error and void:2 is ATT02. The watch is gone — what it guarded left the type position, so there was nothing left to guard.
And the author keeps a way out. acme.outside:1 passes as carrier tier, because that is the author spelling out "this word is mine and the tool does not read it". That is what the three tiers below are for, and it is the exact condition under which being open and being trustworthy hold together.
Attributes come in three tiers
| Tier | Examples | What core does |
|---|---|---|
| structural | path, region, level, the other end of a relation, kind | always read. If it is broken, nothing is read |
| interpreted | h, w, at, edge, daylight, road, site, style … | the ledger defines the value range, and it is read |
| carried | acme.sensor, bems.temp, survey.measured … | not read. Open, with a namespace |
The carried tier takes a dot-separated namespace.
grid X 0 2000
grid Y 0 2000
level L1 0 h:2400 slab:150
space /L1/a room X1..X2 Y1..Y2 name:居間 acme.sensor:23 bems.temp:22.5
space /out outside:1
boundary /L1/a /out✔ Consistent — 1 space / 0 boundaries
Structural consistency only — architectural validity is what koyu validate says, separatelycore gives acme.sensor and bems.temp no meaning whatsoever — it does not check their range and uses them in neither derivation nor judgement. Write anything.
An unknown key without a namespace is an error.
grid X 0 2000
grid Y 0 2000
level L1 0 h:2400 slab:150
space /L1/a room X1..X2 Y1..Y2 nmae:居間
space /out outside:1
boundary /L1/a /out✖ att.muro:line 4: /L1/a carries nmae:, which is not in the ledger (check the spelling, or add a namespace if the value is only carried — e.g. acme.nmae:居間)This used to pass silently. The reasoning was that a word not in the ledger is not wrong, merely uninterpreted, so it went straight into the canonical JSON. The reasoning was consistent and the price was too high — by the same reasoning heigh:2400 silenced the height invariant check, sit:1 silenced site judgement, and stiar:N silenced vertical circulation entirely, all of them staying green.
The namespace is how that boundary is spelled. Carrying without judging is a legitimate state, and saying so explicitly is the condition of the freedom. The attribute ledger is Attributes; the error is detailed in ATT.
The type is the room's purpose
A key called use used to sit beside the type. The two were answering different questions, and only one of them was a question about the room.
The type says what the room is for — office, stair, parking, 厨房. use was for every other division of the building: a tenancy, the lettable-versus-common split, a fire compartment, a department. It held one value per space, so those competed for it and whichever you wrote shut the others out. A room is in a fire compartment and a tenancy and a department at the same time; one key could hold only one of them.
So the other divisions leave the language. Each is a namespaced key of the author's own, and a space carries as many at once as it needs.
grid X 0 6000
grid Y 0 6000
level L1 0 h:2700 slab:200
space /L1/a office X1..X2 Y1..Y2 name:執務室 lease.category:rentable fire.compartment:C1 dept.name:営業
space /out outside:1
boundary /L1/a /out✔ Consistent — 1 space / 0 boundaries
Structural consistency only — architectural validity is what koyu validate says, separatelyTotalling by one of them is koyu stats --by lease.category. The caller names the key and there is no default, because a default would be the one privileged grouping again. use is retired from muro 1.4 (VER07); a file declaring 1.2 or earlier goes on writing it and goes on meaning by it what it always meant.
IFC divides it the same way. IfcSpace has no "use" attribute — a room's purpose is a classification reference (OmniClass table 13, Uniclass SL). Grouping is IfcZone, and one space may be a member of several at once. The building's own occupancy is somewhere else again: Pset_BuildingCommon.OccupancyType, on IfcBuilding rather than on any room.
Where a judgement gets its population
Where free types pay off is in seeing where judgement is entered.
To bring a windowless bathroom into daylight scope, do not change the type — write daylight:1.
grid X 0 2000
grid Y 0 2000
level L1 0 h:2400 slab:150
space /L1/bath wet X1..X2 Y1..Y2 name:浴室 daylight:1
space /out outside:1
boundary /L1/bath /out edge:S t:150
boundary /L1/bath /out edge:E
boundary /L1/bath /out edge:N
boundary /L1/bath /out edge:W /L1/bath 浴室 window 0.00 m2 / floor 4.00 m2 = no window
1 room in daylight scope — these are numbers, not a verdict (koyu validate applies the rule)Change the type from wet to bedroom and nothing about the judgement moves. Daylight scope is not what the room is for, so it is not inferred from the room's name — the author declares it.
This matches practice. Under Japan's Building Standards Act a habitable room is decided by how the room is actually used, not by its label. Note also that the attribute names a behaviour of the tool, not the legal concept — the two are not the same set.
Where a judgement's population really is the room's purpose, the type is where it reads: koyu.schematic.access.parking takes the spaces typed parking or ramp. That is a judgement selecting on a free word — a liberty the face that does not freeze has and the language does not.
The discipline for adding words
An open vocabulary does not mean anything may be added. Five questions settle whether a word or feature is adopted.
- Does it have substance? If so it takes a seat on a relation or on the given. It does not go on a space.
- Is it given? Coordinates that are not given are not written.
- Can several opinions exist at the same seat? If so it goes onto composition's set editing. No bespoke syntax.
- Is it a judgement? Then it belongs to the validation surface, not to the notation.
- Is it form? Then it belongs to the drawing surface, not to the notation.
"Would this let real architecture be written?" is not one of the tests. No decision is recorded with the reservation "we will decide if a real example demands it". A reservation is an entrance for expansion.