name / unit — the building name and the unit

Both are optional; a file with neither still passes check. If you write one, you write it once — a second, different opinion is an error rather than a silent overwrite.

name — the building name

name 街角の複合ビル

name takes the whole rest of the line as its value. The rest is split into neither positionals nor key:value, so a name with spaces in it is written as-is. Write name 3F改修 h:2600 and the h:2600 is part of the building's name — there are no attributes on this line.

The line is read like any other line: everything after # is a comment, quotation marks " are stripped, and runs of whitespace collapse to one space.

name  街角の  複合ビル # 仮称
unit mm
grid X 0 3600
grid Y 0 4000
level L1 0 h:2400 slab:150
space /L1/a room X1..X2 Y1..Y2

The building's name here is 街角の 複合ビル.

$ npx tsx src/cli.ts json nm.muro
{
  "format": "koyu-canonical/1.0",
  "name": "街角の 複合ビル",
  "unit": "mm",

An empty value is an error.

✖ nm.muro:line 1: name takes a value

Once

A model has one building name. Re-declaring the identical string is accepted; a different string is an error — letting the later line win silently would make it unreadable which of the two was the building's name.

name A
name B
grid X 0 3600
grid Y 0 4000

✖ n2.muro:line 2: name is declared once (already "A" — in the base layer when composing)

The discipline is the same when composing: once across all layers. It may sit in the entry or in an imported layer, but if two layers claim different names it is an error, and the provenance of the later one is shown. Keeping the foundation declarations (koyu / name / unit / grid / level) together in the entry is the readable arrangement.

The declaration name is not the attribute name:

The declaration name is the name of the building, and there is one per model. The attribute name: is the display name of a space, a zone, a subdivision, an opening, and so on — one per element. They merely look alike; where they can be written and how many there are both differ.

name 街角の複合ビル                      # the building's name — the whole rest of the line
space /L1/hall hall X1..X2 Y1..Y2 name:エントランスホール   # a space's display name — an attribute

In the canonical JSON the first is the top-level "name" and the second is the element's attrs.name. Neither key is emitted when it was not written.

unit — the unit

unit mm

The only unit is mm. Any other word is an error.

✖ n3.muro:line 1: The only unit in v0 is mm: m

This line is an assertion rather than a declaration: writing it or omitting it leaves the model identical. The canonical JSON emits "unit": "mm" either way.

The whole unit convention is this one table.

Quantity	Unit
Length (coordinates, dimensions, wall thickness, ceiling height, opening width)	mm
A position along a segment	a ratio in 0..1
Reported area	m² (to the wall centerline)
Angle	not writable — direction is carried by the grid and the edge names (N/E/S/W)

A decimal such as 0.1 may appear in a length, but the offset in a grid reference is an integer only (X2+600.5 is rejected as an undefined grid line name).

Where they go

Neither line is indented. name and unit may sit anywhere among the other declarations, but grid and level have to precede their use, which in practice fixes the opening of a file to this order.

koyu 1.0
name 街角の複合ビル
unit mm
grid X 0 6400 12800
grid Y 0 5600
level L1 0 h:3600 slab:600

For the version line, see koyu <version>.