#94 implement default messaging support (#95)

#94 implement default messaging support

allow JS-son agents to send one or several "private" messages as part of a plan to
one or several agents

README.md

@@ -482,6 +482,30 @@ Finally, we run 50 iterations of the scenario:
 environment.run(50)
 ```
 
+## Messaging
+JS-son agents can send "private" messages to any other JS-son agent, which the environment will then relay to this agent only.
+Agents can send these messages in the same way they register the execution of an action as the result of a plan.
+For example, in the plan below, an agent sends the message ``'Hi!'`` to the agent with the ID ``alice``:
+
+```JavaScript
+const messagePlans = [
+  Plan(_ => true, () => ({ messages: [{ message: 'Hi!', agentId: 'alice' }] }))
+]
+```
+
+Assuming that the sending agent has the ID ``bob``, the agent ``alice`` will receive the following belief update:
+
+```JavaScript
+beliefs = {
+  ...beliefs,
+  messages: {
+    bob: ['Hi!']
+  }
+}
+```
+
+Note that messages do not need to be strings, but can be of any type, for example objects.
+
 ## Further Examples
 
 ### Data Science

spec/integration/beliefPlan.spec.js

@@ -23,6 +23,7 @@ const { updateMAS } = require('../mocks/environment')
 describe('Integration: belief-plan approach', () => {
   const human = new Agent('human', beliefs, desires, plans, preferenceFunctionGen)
   const dog = new Agent('dog', dogBeliefs, dogDesires, dogPlans, dogPreferenceFunctionGen)
+  const emptyMessageObject = { human: {}, dog: {} }
 
   const state = {
     dogNice: true,
@@ -39,12 +40,14 @@ describe('Integration: belief-plan approach', () => {
       dogNice: true,
       dogHungry: true,
       foodAvailable: false,
-      dogRecentlyPraised: false
+      dogRecentlyPraised: false,
+      messages: emptyMessageObject
     }, {
       dogNice: true,
       dogHungry: false,
       foodAvailable: false,
-      dogRecentlyPraised: false
+      dogRecentlyPraised: false,
+      messages: emptyMessageObject
     }]
     expect(history).toEqual(expectedHistory)
   })

spec/integration/full.spec.js

@@ -23,6 +23,7 @@ const { updateMAS } = require('../mocks/environment')
 describe('Environment / run()', () => {
   const human = new Agent('human', beliefs, desires, plans, preferenceFunctionGen)
   const dog = new Agent('dog', dogBeliefs, dogDesires, dogPlans, dogPreferenceFunctionGen)
+  const emptyMessageObject = { human: {}, dog: {} }
 
   const state = {
     dogNice: true,
@@ -39,12 +40,15 @@ describe('Environment / run()', () => {
       dogNice: true,
       dogHungry: true,
       foodAvailable: false,
-      dogRecentlyPraised: false
+      dogRecentlyPraised: false,
+      messages: emptyMessageObject
+
     }, {
       dogNice: true,
       dogHungry: false,
       foodAvailable: false,
-      dogRecentlyPraised: false
+      dogRecentlyPraised: false,
+      messages: emptyMessageObject
     }]
     expect(history).toEqual(expectedHistory)
   })

spec/src/environment/Environment.spec.js

@@ -1,4 +1,5 @@
 const Agent = require('../../../src/agent/Agent')
+const Plan = require('../../../src/agent/Plan')
 const Environment = require('../../../src/environment/Environment')
 
 const {
@@ -17,28 +18,31 @@ const {
 
 console.log = jasmine.createSpy('log')
 
+const emptyMessageObject = { human: {}, dog: {} }
+
 describe('Environment / run()', () => {
   const human = new Agent('human', beliefs, desires, plans, preferenceFunctionGen)
+  const dog = new Agent('dog', dogBeliefs, dogDesires, dogPlans, dogPreferenceFunctionGen)
 
   const state = {
     dogNice: true,
     dogHungry: true
   }
 
   const update = actions => (actions.some(
-    action => action.actions.includes('Here, take some food!')) ? { dogHungry: false } : {}
+    action => action.actions &&
+      action.actions.includes('Here, take some food!')) ? { dogHungry: false } : {}
   )
 
   it('Should process agent actions', () => {
     const environment = new Environment([human], state, update)
     environment.run(1)
-    expect(console.log).toHaveBeenCalledWith({ dogNice: true, dogHungry: false })
+    expect(console.log).toHaveBeenCalledWith(
+      { dogNice: true, dogHungry: false, messages: { human: {} } }
+    )
   })
 
   it('Should allow agent-to-agent interaction', () => {
-    const dog = new Agent('dog', dogBeliefs, dogDesires, dogPlans, dogPreferenceFunctionGen)
-    // console.log(dog)
-    // const dog = createAgent('dog')
     const updateMAS = actions => {
       const stateUpdate = {}
       actions.forEach(action => {
@@ -67,40 +71,42 @@ describe('Environment / run()', () => {
       dogNice: true,
       dogHungry: true,
       foodAvailable: false,
-      dogRecentlyPraised: false
+      dogRecentlyPraised: false,
+      messages: emptyMessageObject
     }, {
       dogNice: true,
       dogHungry: false,
       foodAvailable: false,
-      dogRecentlyPraised: false
+      dogRecentlyPraised: false,
+      messages: emptyMessageObject
     }]
-    expect(JSON.stringify(history)).toEqual(JSON.stringify(expectedHistory))
+    expect(history).toEqual(expectedHistory)
   })
 
   it('Should terminate after the specified number of iterations', () => {
     const environment = new Environment([human], state, update)
     const history = environment.run(2)
     const expectedHistory = [
-      { dogNice: true, dogHungry: true },
-      { dogNice: true, dogHungry: false },
-      { dogNice: true, dogHungry: false }
+      { dogNice: true, dogHungry: true, messages: { human: {} } },
+      { dogNice: true, dogHungry: false, messages: { human: {} } },
+      { dogNice: true, dogHungry: false, messages: { human: {} } }
     ]
     expect(history).toEqual(expectedHistory)
   })
 
   it('Should allow for the specification of a custom runner function', () => {
     const environment = new Environment(
-      [human],
+      [human, dog],
       state,
       update,
       state => console.log(state),
       state => state
     )
     const history = environment.run(2)
     const expectedHistory = [
-      { dogNice: true, dogHungry: true },
-      { dogNice: true, dogHungry: false },
-      { dogNice: true, dogHungry: false }
+      { dogNice: true, dogHungry: true, messages: emptyMessageObject },
+      { dogNice: true, dogHungry: false, messages: emptyMessageObject },
+      { dogNice: true, dogHungry: false, messages: emptyMessageObject }
     ]
     expect(history).toEqual(expectedHistory)
   })
@@ -125,30 +131,58 @@ describe('Environment / run()', () => {
       return state
     }
     const history1 = new Environment(
-      [human],
+      [human, dog],
       state,
       update,
       state => console.log(state),
       stateFilter1
     ).run(2)
     const expectedHistory1 = [
-      { dogNice: true, dogHungry: true },
-      { dogNice: true, dogHungry: true },
-      { dogNice: true, dogHungry: true }
+      { dogNice: true, dogHungry: true, messages: emptyMessageObject },
+      { dogNice: true, dogHungry: true, messages: emptyMessageObject },
+      { dogNice: true, dogHungry: true, messages: emptyMessageObject }
     ]
     expect(history1).toEqual(expectedHistory1)
     const history2 = new Environment(
-      [human],
+      [human, dog],
       state,
       update,
       state => console.log(state),
       stateFilter2
     ).run(2)
     const expectedHistory2 = [
-      { dogNice: true, dogHungry: true },
-      { dogNice: true, dogHungry: false },
-      { dogNice: true, dogHungry: false }
+      { dogNice: true, dogHungry: true, messages: emptyMessageObject },
+      { dogNice: true, dogHungry: false, messages: emptyMessageObject },
+      { dogNice: true, dogHungry: false, messages: emptyMessageObject }
     ]
     expect(history2).toEqual(expectedHistory2)
   })
+
+  it('Should allow for agent-to-agent message passing', () => {
+    const messagePlans = [
+      Plan(_ => true, () => ({ messages: [{ message: 'Hi!', agentId: 'human' }] }))
+    ]
+    const filledMessageObject = {
+      ...emptyMessageObject,
+      human2: {},
+      human: { human2: ['Hi!'] }
+    }
+    const human2 = new Agent('human2', beliefs, desires, messagePlans, preferenceFunctionGen)
+    const env = new Environment(
+      [human, human2, dog],
+      state,
+      update
+    )
+    const history = env.run(2)
+    const expectedHistory = [
+      { dogNice: true, dogHungry: true, messages: filledMessageObject },
+      { dogNice: true, dogHungry: false, messages: filledMessageObject },
+      { dogNice: true, dogHungry: false, messages: filledMessageObject }
+    ]
+    expect(history).toEqual(expectedHistory)
+    expect(env.agents.human.beliefs.messages.human2).toContain('Hi!')
+    expect(env.agents.human.beliefs.messages.human2.length).toEqual(1)
+    expect(env.agents.human2.beliefs.messages.human2.length).toEqual(0)
+    expect(env.agents.dog.beliefs.messages.human2.length).toEqual(0)
+  })
 })

src/environment/Environment.js

@@ -22,9 +22,13 @@ function Environment (
     }
   }
 ) {
-  this.agents = {}
-  agents.forEach(agent => (this.agents[agent.id] = agent))
+  state.messages = {}
   this.state = state
+  this.agents = {}
+  agents.forEach(agent => {
+    this.agents[agent.id] = agent
+    this.state.messages[agent.id] = {}
+  })
   this.update = update
   this.render = render
   this.stateFilter = stateFilter
@@ -35,9 +39,34 @@ function Environment (
     this.history.push(this.state)
     const run = () => {
       Object.keys(this.agents).forEach(agentKey => {
+        const messages = {}
+        Object.keys(this.state.messages).forEach(recipient => {
+          Object.keys(this.state.messages[recipient]).forEach(sender => {
+            if (recipient !== agentKey) {
+              messages[sender] = []
+              return
+            }
+            messages[sender] = this.state.messages[recipient][sender]
+          })
+        })
+        const preFilteredState = { ...this.state, messages }
         const proposedUpdate = this.agents[agentKey].next(
-          this.stateFilter(this.state, agentKey, this.agents[agentKey].beliefs)
-        )
+          this.stateFilter(preFilteredState, agentKey, this.agents[agentKey].beliefs))
+        proposedUpdate.forEach(action => {
+          Object.keys(this.state.messages).forEach(key => {
+            if (this.state.messages[key][agentKey]) this.state.messages[key][agentKey] = []
+          })
+          if (action.messages) {
+            action.messages.forEach(
+              message => {
+                if (!this.state.messages[[message.agentId]][agentKey]) {
+                  this.state.messages[[message.agentId]][agentKey] = []
+                }
+                this.state.messages[message.agentId][agentKey].push(message.message)
+              }
+            )
+          }
+        })
         const stateUpdate = this.update(proposedUpdate, agentKey, this.state)
         this.state = {
           ...this.state,