first drop

src/Action.js

@@ -1,12 +1,13 @@
 class Action {
   constructor({
-    id, name, then, priority, final,
+    id, name, then, priority, final, activationGroup,
   }) {
     this.id = id;
     this.name = name; // for logging only
     this.then = then;
     this.priority = priority;
     this.final = final;
+    this.activationGroup = activationGroup;
     this.premises = [];
   }
 

src/Rools.js

@@ -69,7 +69,10 @@ class Rools {
     // create agenda for actions
     const actionsAgenda = pass === 0 ? memory.actions : premisesAgenda
       .reduce((acc, premise) => [...new Set([...acc, ...premise.actions])], [])
-      .filter(action => !memory.getState(action).fired);
+      .filter((action) => {
+        const { fired, discarded } = memory.getState(action);
+        return !fired && !discarded;
+      });
     this.logger.debug({ message: `actions agenda length ${actionsAgenda.length}` });
     // evaluate actions
     actionsAgenda.forEach((action) => {
@@ -78,8 +81,8 @@ class Rools {
     });
     // create conflict set
     const conflictSet = memory.actions.filter((action) => { // all actions not only actionsAgenda!
-      const { fired, ready } = memory.getState(action);
-      return ready && !fired;
+      const { fired, ready, discarded } = memory.getState(action);
+      return ready && !fired && !discarded;
     });
     this.logger.debug({ message: `conflict set length ${conflictSet.length}` });
     // conflict resolution
@@ -104,11 +107,18 @@ class Rools {
     } finally {
       delegator.unset();
     }
-    // check final rule
+    // final rule
     if (action.final) {
       this.logger.debug({ message: 'evaluation stop after final rule', rule: action.name });
       return false; // done
     }
+    // activation group
+    if (action.activationGroup) {
+      this.rules.actionsByActivationGroup[action.activationGroup].forEach((other) => {
+        const state = memory.getState(other);
+        state.discarded = !state.fired;
+      });
+    }
     // continue with next pass
     return true;
   }

src/Rule.js

@@ -4,14 +4,15 @@ const { arrify } = require('./utils');
 
 class Rule {
   constructor({
-    name, when, then, priority = 0, final = false, extend,
+    name, when, then, priority = 0, final = false, extend, activationGroup,
   }) {
     this.name = name;
     this.when = arrify(when);
     this.then = then;
     this.priority = priority;
     this.final = final;
     this.extend = arrify(extend);
+    this.activationGroup = activationGroup;
     this.assert();
   }
 
@@ -52,6 +53,10 @@ class Rule {
       this.extend.reduce((acc, rule) => acc && (rule instanceof Rule), true),
       '"extend" must be a Rule or an array of Rules',
     );
+    assert(
+      !this.activationGroup || _.isString(this.activationGroup),
+      '"activationGroup" must be a string',
+    );
   }
 }
 

src/RuleSet.js

@@ -12,6 +12,7 @@ class RuleSet {
     this.premisesByHash = {};
     this.nextActionId = uniqueid('a');
     this.nextPremiseId = uniqueid('p');
+    this.actionsByActivationGroup = {}; // hash
   }
 
   register(rule) {
@@ -49,6 +50,16 @@ class RuleSet {
       action.add(premise); // action ->> premises
       premise.add(action); // premise ->> actions
     });
+    // activation group
+    const { activationGroup } = rule;
+    if (activationGroup) {
+      let group = this.actionsByActivationGroup[activationGroup];
+      if (!group) {
+        group = [];
+        this.actionsByActivationGroup[activationGroup] = group;
+      }
+      group.push(action);
+    }
   }
 }
 

src/WorkingMemory.js

@@ -7,7 +7,7 @@ class WorkingMemory {
     this.actionsById = {}; // hash
     this.premisesById = {}; // hash
     this.actions.forEach((action) => {
-      this.actionsById[action.id] = { ready: false, fired: false };
+      this.actionsById[action.id] = { ready: false, fired: false, discarded: false };
     });
     this.premises.forEach((premise) => {
       this.premisesById[premise.id] = { value: undefined };