require-macros:
   earl-mocha ->
      describe, it, before, after, before-each, after-each
      xdescribe, xit
      assert, asserts
      expect-error

require:
   ..src ->
      deprox, read-proxy, write-proxy, Directory, ID
      Patch, Tracks
      reactive-function, System
   ..src/reactive ->
      State, DependentState
      reactive-function2
   .people ->
      static-dir
      alice, bob, clara, donald, emily, francis, gerard, helen
      aid, bid, cid, did, eid, fid, gid, hid


count-calls{f} =
   rval{*args} =
      rval.count += 1
      f.apply{this, args}
   rval.count = 0
   rval

predicate! ArrayProx{p} =
   Array? deprox{p}


describe "Reactive functions":

   before-each:

      count-calls! reactive-function2! @say-name{person} =
         {greeting = 'Hello, my name is {person.name}!'}

      count-calls! reactive-function2! @say-names{people} =
         people each
            ArrayProx? subp -> @say-names{subp}
            person -> 'Hello, my name is {person.name}!'

      count-calls! reactive-function2! @say-parent-names{person} =
         {mother = @say-name{person.mother}
          father = @say-name{person.father}}

      count-calls! reactive-function2! @nameo{match} =
         {=> name, => age, => mother = null, => father = null} ->
            {name = name + "-o", age = age
             mother = mother and @nameo{mother}
             father = father and @nameo{father}}


   it "called through System":
      state = State{clara}
      dstate = DependentState{state, @say-name}
      assert dstate.get{} == {greeting = 'Hello, my name is clara!'}

   it "modify":
      state = State{clara}
      dstate = DependentState{state, @say-name}
      state.transact with {clara} ->
         clara.name = .brigitte
      assert dstate.get{} == {greeting = 'Hello, my name is brigitte!'}

   it "multiple listeners":
      state = State{clara}
      dstate1 = DependentState{state, @say-name}
      dstate2 = DependentState{state, @say-parent-names}
      state.transact with {clara} ->
         clara.name = .brigitte
         clara.mother.name = .flora
      assert dstate1.get{} == {greeting = 'Hello, my name is brigitte!'}
      assert dstate2.get{} == {
         mother = {greeting = 'Hello, my name is flora!'}
         father = {greeting = 'Hello, my name is bob!'}
      }

   it "pipeline":

      state = State{clara}

      dstate1 = DependentState{state, @nameo, clobber-patch = false}
      assert dstate1.get{} == {
         name = "clara-o"
         age = 20
         mother = {name = "alice-o", age = 51, mother = null, father = null}
         father = {name = "bob-o", age = 56, mother = null, father = null}
      }

      dstate2 = DependentState{dstate1, @nameo, clobber-patch = false}
      assert dstate2.get{} == {
         name = "clara-o-o"
         age = 20
         mother = {name = "alice-o-o", age = 51, mother = null, father = null}
         father = {name = "bob-o-o", age = 56, mother = null, father = null}
      }


      ;; Sub-field changes
      state.transact with {clara} ->
         clara.father.name = .roger

      assert dstate1.get{} == {
         name = "clara-o"
         age = 20
         mother = {name = "alice-o", age = 51, mother = null, father = null}
         father = {name = "roger-o", age = 56, mother = null, father = null}
      }

      assert dstate2.get{} == {
         name = "clara-o-o"
         age = 20
         mother = {name = "alice-o-o", age = 51, mother = null, father = null}
         father = {name = "roger-o-o", age = 56, mother = null, father = null}
      }


      ;; Root changes
      state.transact with {clara} ->
         clara.name = .brigitte
         clara.mother.name = .flora

      assert dstate1.get{} == {
         name = "brigitte-o"
         age = 20
         mother = {name = "flora-o", age = 51, mother = null, father = null}
         father = {name = "roger-o", age = 56, mother = null, father = null}
      }

      assert dstate2.get{} == {
         name = "brigitte-o-o"
         age = 20
         mother = {name = "flora-o-o", age = 51, mother = null, father = null}
         father = {name = "roger-o-o", age = 56, mother = null, father = null}
      }