Native Graph V2

MODEL "Native Graph V2"
DESCRIPTION "Closed kinds, typed views, immutable rewrites, declarative paths, partitions, bounded patterns, and fixed-point propagation."
VERSION "1.0.0"
TAGS "graph", "schema", "kind", "view", "rewrite", "path", "partition", "pattern", "fixpoint"

graph schema Roads {
  node kind City
  edge kind Road: City -> City
  node.kind: string
  edge.kind: string
  edge.minutes: number
  edge.capacity: number
  edge.open: boolean
}

graph roads: Roads = GRAPH(
  [
    ["node_id", "kind"],
    ["A", "City"],
    ["B", "City"],
    ["C", "City"],
    ["D", "City"]
  ] AS nodes,
  "node_id" AS node_id,
  ["kind"] AS node_properties,
  [
    ["edge_id", "from", "to", "kind", "minutes", "capacity", "open"],
    ["ab", "A", "B", "Road", 4, 20, TRUE],
    ["bc", "B", "C", "Road", 7, 8, TRUE],
    ["ac", "A", "C", "Road", 15, 30, FALSE],
    ["cd", "C", "D", "Road", 3, 12, TRUE]
  ] AS edges,
  "edge_id" AS edge_id,
  "from" AS from,
  "to" AS to,
  ["kind", "minutes", "capacity", "open"] AS edge_properties,
  TRUE AS directed
)

# A single selective scalar consumer lets Graph MIR fuse this view.
graph open_roads: Roads = roads {
  edge road where road.open = TRUE
}
R1C1 = GRAPH_EDGE_COUNT(open_roads)

# Rewrites are immutable and publish only after the complete bounded edit set validates.
graph normalized: Roads = rewrite roads limit 100:
  match (origin)-[closed where closed.open = FALSE]->(destination)
  delete closed
R1C2 = GRAPH_EDGE_COUNT(normalized)

# Source expresses the objective. EXPLAIN shows the chosen physical kernel.
path fastest = path in roads from "A" to "D"
  minimize sum(edge.minutes)
  limit 8 AS hops

path resilient = path in roads from "A" to "D"
  maximize min(edge.capacity)
  limit 8 AS hops

R1C3 = fastest.cost
R1C4 = fastest.hops
frame fastest_nodes = fastest.nodes
frame fastest_edges = fastest.edges

partition communities = partition nodes of roads by community(
  leiden AS method,
  modularity(1 AS resolution) AS objective,
  edge.capacity AS weight,
  directed AS direction,
  0 AS seed,
  all AS hierarchy,
  50 AS max_passes,
  16 AS max_levels,
  0.000000001 AS tolerance
)

frame community_membership = communities.members
frame community_summary = communities.summary

# Contraction consumes the resident partition, keeps cross-community edges as
# a deterministic multigraph, and exposes the quotient as another GraphHandle.
graph quotient = contract roads by communities
R1C5 = GRAPH_NODE_COUNT(quotient)

frame open_two_hop_routes = match roads limit 100:
  (origin)-[first where first.open = TRUE]->(middle)-[second where second.open = TRUE]->(destination)
  return origin as origin, middle as middle, destination as destination,
         first.minutes as first_minutes, second.minutes as second_minutes

frame travel_minutes = fixpoint in roads:
  using min_plus(edge.minutes AS weight)
  along AS direction
  1000000000 AS default
  0 AS seed "A"
  until max_delta < 0.000000001
  within 16 iterations

END MODEL