README.md

@@ -1,93 +1,2 @@
 # GraphECS
 this is a prototype demonstrating representing underlying ecs data as a graph with a cypher-like query language
-
-## Syntax
-graphecs uses a modified subset of neo4j's [cypher](https://neo4j.com/docs/cypher-manual/current/introduction/) query language. neo4j is a graph database with a focus on relationships between data. it has many similar features to SQL-like languages but the ergonomics of relating data is significantly better.
-
-### Querying entities
-
-```cypher
-MATCH (e)
-RETURN e
-```
-
-this is a basic query to return every entity in current ecs world. `MATCH` clauses begin any expression that queries for data. `RETURN` defines what data will be returned by the query. an example of the output may look like this
-
-```js
-[
-    { e: 0 },
-    { e: 1 },
-    { e: 2 },
-]
-```
-
-```cypher
-MATCH (e:Entity, :Player)
-RETURN e
-```
-
-this query specifies two components to match for a single node. here, it explicitly identifies the `:Entity` component but this is optional -- binding a variable without any component label will be bound to the entity's id. additionally, it requires the node to also have the `Player` component. it doesn't bind that component to any variable, however. matching against multiple components in a single node acts like an AND operator -- in this case, `Entity AND Player`.
-
-```cypher
-MATCH (:Player)-[:Knows]->(n:NPC)
-RETURN n
-```
-
-this query matches against a relationship: any `Player` which `Knows` an `NPC`. it will return a list of all NPCs which have this relationship with the player. in the prototype, edges are just entities with `from` and `to` properties
-
-```js
-const Item = defineComponent({ damage: Types.ui8 })
-query('MATCH (item:Item) RETURN item.damage', engine)
-```
-
-in this example, we have an `Item` component with a single property: `damage`. it can be useful to only return a single property from a component. the result of this query may look like the following
-
-```js
-[
-    { item: { damage: 10 } },
-    { item: { damage: 15 } },
-    { item: { damage: 20 } },
-]
-```
-
-accessing nested data like this can get a bit unwieldy, but its possible to alias variables
-
-```cypher
-MATCH (item:Item)
-RETURN item.damage AS damage
-```
-
-```js
-[
-    { damage: 10 },
-    { damage: 15 },
-    { damage: 20 },
-]
-```
-
-### Filtering queries
-
-```cypher
-MATCH (h:Health)
-WHERE h.current < 10
-RETURN h
-```
-
-it is also possible to filter results via the `WHERE` clause. the following operators are supported in graphecs: `> >= < <= = AND OR XOR ( )`
-
-```cypher
-MATCH (n)-[d:Damaged]->(e, h:Health)
-WHERE d.damage > h.current AND h.current > 0
-RETURN e
-```
-
-this would return every entity id that has a relationship that deals more damage than its remaining health and isn't already dead
-
-### Selecting worlds
-```cypher
-USE ui
-MATCH (button:Button)
-WHERE button.type = 1
-RETURN button
-```
-it's also possible to select different worlds with the `USE` clause

src/query-parser/types.js

@@ -1,4 +1,4 @@
-import { curry, is, last, mergeRight, mergeRightDeep, path } from '../fn.js'
+import { curry, is, last, mergeRightDeep, path } from '../fn.js'
 import { Stream } from '../stream.js'
 
 class Value {
@@ -99,7 +99,7 @@ export class Function {
     const result = []
     let n = Math.min(this.length, stack.length)
 
-    while (n > 0) {
+    while(n > 0) {
       result.push(stack.pop())
       n--
     }
@@ -220,21 +220,23 @@ export class Filter {
     return output
   }
 
-  passes(node) {
+  passes(nodes) {
-    const values = this.values.map(v => v.from ? v.from(node.values) : v)
+    return nodes.every(node => {
-    const stream = new Stream(values)
+      const values = this.values.map(v => v.from ? v.from(node.values) : v)
-    const stack = []
+      const stream = new Stream(values)
-    while (!stream.done()) {
+      const stack = []
-      const next = stream.next()
+      while (!stream.done()) {
-      if (is(Operator, next)) {
+        const next = stream.next()
-        const result = next.apply(stack)
+        if (is(Operator, next)) {
-        stack.push(result)
+          const result = next.apply(stack)
-      } else {
+          stack.push(result)
-        stack.push(next)
+        } else {
+          stack.push(next)
+        }
       }
-    }
 
-    return stack[0]
+      return stack[0]
+    })
   }
 }
 

src/query.js

@@ -50,16 +50,14 @@ const queryRelationship = (query, world) => {
     return node.relationship ? node.from : node
   })
 
-  const [fc, tc] = [from, to].map(n => n.components.filter(notEntity).map(prop('type')))
+  const matchesFrom = matches(world, from.components.map(prop('type')), from.query(world))
-  const matchesFrom = matches(world, fc, from.query(world))
+  const matchesTo = matches(world, to.components.map(prop('type')))
-  const matchesTo = matches(world, tc)
 
   const Edge = edge.components[0].type
   const edges = edge.query(world)
   const result = []
   for (let i = 0; i < edges.length; i++) {
     const eid = edges[i]
-    // console.log(eid, Edge.from[eid], '->', Edge.to[eid], matchesFrom(Edge.from[eid]), matchesTo(Edge.to[eid]))
 
     if (matchesFrom(Edge.from[eid]) && matchesTo(Edge.to[eid])) {
       result.push(eid)
@@ -144,7 +142,7 @@ const resolveValues = query => {
       }
     })
 
-    return values.flat().reduce(mergeRightDeep)
+    return values.flat()
   })
 }
 
@@ -153,7 +151,7 @@ const filterValues = curry((filters, values) => {
 })
 
 const resolveReturns = curry((returnValues, values) => {
-  return values.map(x => returnValues.from(x.values))
+  return values.map(x => x.map(y => returnValues.from(y.values)))
 })
 
 export const query = curry((input, { world, component }) => {
@@ -165,7 +163,7 @@ export const query = curry((input, { world, component }) => {
     const values = resolveValues(results)
     const filtered = filterValues(filters, values)
     const returns = resolveReturns(returnValues, filtered)
-    return returns
+    return map(reduce(mergeRightDeep, {}), returns)
   })
 })
 

tests/query.test.js

@@ -115,37 +115,31 @@ describe('query', () => {
         const [edge] = relate(world, player, Damaged, enemy)
         update(Damaged, { damage: 10 }, edge)
 
-        // assert.deepEqual(
-        //     query('MATCH (e, h:Health) WHERE h.current < 30 RETURN e, h.max', engine).unwrap(),
-        //     [{ e: 12, h: { max: 50 } }]
-        // )
-
-        // assert.deepEqual(
-        //     query('MATCH (e, h:Health) WHERE e = 13 AND h.max = 50 OR h.current < 25 RETURN e, h.max', engine).unwrap(),
-        //     [{ e: 13, h: { max: 50 } }]
-        // )
-
-        // assert.deepEqual(
-        //     query('MATCH (e, h:Health) WHERE h.max = 50 OR h.current > 45 RETURN e, h.max AS maxHealth', engine).unwrap(),
-        //     [
-        //         { e: 12, maxHealth: 50 },
-        //         { e: 13, maxHealth: 50 }
-        //     ]
-        // )
-        // assert.deepEqual(
-        //     query('MATCH (e, :Player, h:Health) WHERE (h.max = 50 OR h.current > 45) AND e = 12 RETURN e, h.max AS maxHealth', engine).unwrap(),
-        //     [{ e: 12, maxHealth: 50 }]
-        // )
-
-        // assert.deepEqual(
-        //     query('MATCH (:Player)-[d:Damaged]->(h:Health) RETURN h.current AS health, d.damage AS damage', engine).unwrap(),
-        //     [{ damage: 10, health: 35 }]
-        // )
-
-        update(Damaged, { damage: 50 }, edge)
         assert.deepEqual(
-            query('MATCH (n)-[d:Damaged]->(e, h:Health) WHERE d.damage > h.current AND h.current > 0 RETURN e', engine).unwrap(),
+            query('MATCH (e, h:Health) WHERE h.current < 30 RETURN e, h.max', engine).unwrap(),
-            [{ e: 13 }]
+            [{ e: 12, h: { max: 50 } }]
+        )
+
+        assert.deepEqual(
+            query('MATCH (e, h:Health) WHERE e = 13 AND h.max = 50 OR h.current < 25 RETURN e, h.max', engine).unwrap(),
+            [{ e: 13, h: { max: 50 } }]
+        )
+
+        assert.deepEqual(
+            query('MATCH (e, h:Health) WHERE h.max = 50 OR h.current > 45 RETURN e, h.max AS maxHealth', engine).unwrap(),
+            [
+                { e: 12, maxHealth: 50 },
+                { e: 13, maxHealth: 50 }
+            ]
+        )
+        assert.deepEqual(
+            query('MATCH (e, :Player, h:Health) WHERE (h.max = 50 OR h.current > 45) AND e = 12 RETURN e, h.max AS maxHealth', engine).unwrap(),
+            [{ e: 12, maxHealth: 50 }]
+        )
+
+        assert.deepEqual(
+            query('MATCH (:Player)-[d:Damaged]->(h:Health) RETURN h.current AS health, d.damage AS damage', engine).unwrap(),
+            [{ damage: 10, health: 35 }]
         )
     })
 })