Relational placement

By default a room is positioned with absolute coordinates:

room id=living at (0,0) size 5000x4000 label "Living"

Since v1.0 a room can instead be positioned relative to another room, and the compiler resolves its absolute coordinates for you — by pure arithmetic, in dependency order. This is sugar over absolute coordinates: it is fully deterministic and is not an optimizer (see ADR 0004).

Syntax

room [id=NAME] DIRECTION REF [align EDGE] [gap N] size WxH [label "…"]

• DIRECTION — one of right-of, left-of, below, above.
• REF — the id of another room to place against.
• align EDGE (optional) — which edges line up on the cross axis:
  • horizontal placement (right-of / left-of): top · middle · bottom
  • vertical placement (below / above): left · center · right
  • default: the leading edge (top for horizontal, left for vertical).
• gap N (optional) — spacing in mm along the placement axis (default 0).

Example

plan "Relational 1BR" {
  units mm
  grid 50

  room id=living  at (0,0)                        size 5000x4000 label "Living"
  room id=kitchen right-of living align top gap 0 size 3000x4000 label "Kitchen"
  room id=bed     below living    align left gap 0 size 5000x3500 label "Bedroom"
  room id=bath    right-of bed    align top  gap 0 size 3000x3500 label "Bath"
}

Only living is anchored; every other room derives its position from a neighbour, so moving the anchor or resizing a room reflows the whole plan deterministically.

Placement arithmetic

For reference room R, new room N, and gap g:

Direction	Position
right-of	N.x = R.x + R.w + g; N.y from align (top/middle/bottom)
left-of	N.x = R.x − N.w − g; N.y from align
below	N.y = R.y + R.h + g; N.x from align (left/center/right)
above	N.y = R.y − N.h − g; N.x from align

Computed coordinates are grid-snapped exactly like absolute ones.

Diagnostics

• E_LAYOUT_CYCLE — rooms reference each other in a loop, so no order resolves them. Break the cycle by giving one room absolute at (x,y) coordinates.
• E_LAYOUT_REF — a relational clause names a room id that does not exist. Reference an existing room, or fix the typo.