From 77676085950bf70f6993c18a6a6d9e7dcc4771f5 Mon Sep 17 00:00:00 2001
From: Steven Hugg <hugg@fasterlight.com>
Date: Sat, 19 Feb 2022 18:20:03 -0600
Subject: [PATCH] ecs: query takes [#entity] list

---
 src/common/ecs/compiler.ts | 20 +++++++++++++++++---
 src/common/ecs/ecs.ts      | 23 +++++++++++++++++------
 2 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/src/common/ecs/compiler.ts b/src/common/ecs/compiler.ts
index 9d743758..db2274ac 100644
--- a/src/common/ecs/compiler.ts
+++ b/src/common/ecs/compiler.ts
@@ -170,12 +170,16 @@ export class ECSCompiler extends Tokenizer {
         if (tok.str == '#') {
             this.consumeToken();
             let reftype = field.dtype == 'ref' ? field as RefType : undefined;
-            let token = this.expectIdent();
-            return { reftype, token };
+            return this.parseEntityForwardRef(reftype);
         }
         this.compileError(`I expected a ${field.dtype} here.`); throw new Error();
     }
 
+    parseEntityForwardRef(reftype?: RefType) : ForwardRef {
+        let token = this.expectIdent();
+        return { reftype, token };
+    }
+
     parseDataArray() {
         this.expectToken('[');
         let arr = this.parseList(this.expectInteger, ',');
@@ -283,12 +287,22 @@ export class ECSCompiler extends Tokenizer {
         if (prefix.type != TokenType.Ident) {
             this.consumeToken();
         }
-        let cref = this.parseComponentRef();
         if (prefix.type == TokenType.Ident) {
+            let cref = this.parseComponentRef();
             q.include.push(cref);
         } else if (prefix.str == '-') {
+            let cref = this.parseComponentRef();
             if (!q.exclude) q.exclude = [];
             q.exclude.push(cref);
+        } else if (prefix.str == '#') {
+            const scope = this.currentScope;
+            if (scope == null) { this.internalError(); throw new Error(); }
+            let eref = this.parseEntityForwardRef();
+            this.deferred.push(() => {
+                let refvalue = this.resolveEntityRef(scope, eref);
+                if (!q.entities) q.entities = [];
+                q.entities.push(scope.entities[refvalue]);
+            });
         } else {
             this.compileError(`Query components may be preceded only by a '-'.`);
         }
diff --git a/src/common/ecs/ecs.ts b/src/common/ecs/ecs.ts
index 563588cc..2a1c9448 100644
--- a/src/common/ecs/ecs.ts
+++ b/src/common/ecs/ecs.ts
@@ -46,6 +46,7 @@ export interface ComponentType extends SourceLocated {
 export interface Query extends SourceLocated {
     include: ComponentType[]; // TODO: make ComponentType
     exclude?: ComponentType[];
+    entities?: Entity[];
     limit?: number;
 }
 
@@ -503,10 +504,18 @@ class EntitySet {
     constructor(scope: EntityScope, query?: Query, a?: EntityArchetype[], e?: Entity[]) {
         this.scope = scope;
         if (query) {
-            this.atypes = scope.em.archetypesMatching(query);
-            this.entities = scope.entitiesMatching(this.atypes);
-            if (query.limit) {
-                this.entities = this.entities.slice(0, query.limit);
+            if (query.entities) {
+                this.entities = query.entities.slice(0);
+                this.atypes = [];
+                for (let e of this.entities)
+                    if (!this.atypes.includes(e.etype))
+                        this.atypes.push(e.etype);
+            } else {
+                this.atypes = scope.em.archetypesMatching(query);
+                this.entities = scope.entitiesMatching(this.atypes);
+                if (query.limit) {
+                    this.entities = this.entities.slice(0, query.limit);
+                }
             }
         } else if (a && e) {
             this.atypes = a;
@@ -751,8 +760,10 @@ class ActionEval {
                 throw new ECSError('unroll is not yet implemented');
             }
             // define properties
-            props['%elo'] = entities[0].id.toString();
-            props['%ehi'] = entities[entities.length - 1].id.toString();
+            if (entities.length) {
+                props['%elo'] = entities[0].id.toString();
+                props['%ehi'] = entities[entities.length - 1].id.toString();
+            }
             props['%ecount'] = entities.length.toString();
             props['%efullcount'] = fullEntityCount.toString();
             // TODO