📝 Update examples

Author: jandudulski

examples/decide.md

@@ -18,7 +18,7 @@ decider = Decider.define do
 end
 
 decider.decide Command.new(value: 10), decider.initial_state
-#> [Event.new(value: 15)]
+#> [#<data Event value=15>]
 ```
 
 ## Match by command and state
@@ -138,7 +138,7 @@ decider = Decider.define do
     emit [:started, command.value]
   end
 
-  decide proc { [command, state] in [Stop, [:started, _]] } do
+  decide proc { [command, state] in [Stop, :started] } do
     emit :stopped
   end
 end

examples/evolve.md

@@ -1,25 +1,88 @@
 # Evolve
 
-## Handling unknown events
+## Match by event
 
 ```ruby
+Event = Data.define(:value)
+
 decider = Decider.define do
   initial_state :initial
+
+  evolve Event do
+    event.value
+  end
 end
+
+decider.evolve decider.initial_state, Event.new(value: :changed)
+#> :changed
 ```
 
-Return state (nothing changed) by default:
+## Match by state and event
 
 ```ruby
+decider = Decider.define do
+  initial_state :turned_off
+
+  evolve :turned_on, :turned_off do
+    event
+  end
+
+  evolve :turned_off, :turned_on do
+    event
+  end
+end
+
+decider.evolve decider.initial_state, :turned_on
+#> :turned_on
+decider.evolve :turned_on, :turned_off
+#> :turned_off
+decider.evolve :turned_on, :unknown
+#> :turned_on
+```
+
+## Match by pattern matching
+
+```ruby
+State = Data.define(:value)
+Event = Data.define(:value)
+
+decider = Decider.define do
+  initial_state State.new(value: :turned_off)
+
+  evolve proc { [state, event] in [State(value: :turned_off), Event(value: :turned_on)] } do
+    state.with(value: event.value)
+  end
+end
+
+decider.evolve decider.initial_state, Event.new(value: :turned_on)
+#> #<data State value=:turned_on>
 decider.evolve decider.initial_state, :unknown
+#> #<data State value=:turned_off>
+```
+
+## Handling unknown events
+
+```ruby
+decider = Decider.define do
+  initial_state :initial
+end
+
+decider.decide decider.initial_state, :initial
 #> :initial
 ```
 
-Raise error when using `evolve!`:
+If you want to raise error, define a catch-all as last one:
 
 ```ruby
-decider.evolve! decider.initial_state, :unknown
-#> raise ArgumentError, Unknown event
+decider = Decider.define do
+  initial_state :initial
+
+  evolve proc { true } do
+    raise ArgumentError, "Unknown event #{event}"
+  end
+end
+decider.evolve decider.initial_state, :unknown
+#> Unknown event unknown (ArgumentError)
 ```
 
 ## Events
@@ -30,11 +93,11 @@ Events can be primitives like symbols:
 decider = Decider.define do
   initial_state :initial
 
-  evolve :started do |state, event|
+  evolve :started do
     :started
   end
 
-  evolve :stopped do |state, event|
+  evolve :stopped do
     :stopped
   end
 end
@@ -50,13 +113,38 @@ Stopped = Data.define
 decider = Decider.define do
   initial_state State.new(speed: 0)
 
-  evolve Started do |state, event|
-    State.new(speed: event.speed)
+  evolve State, Started do
+    state.with(speed: event.speed)
   end
 
-  evolve Stopped do |state, event|
+  evolve State, Stopped do
     State.new(speed: 0)
   end
 end
 ```
 
+## Calculate state
+
+In most cases you want to take a collection of events and reduce them with `evolve` to calculate the state, like:
+
+```ruby
+decider = Decider.define do
+  initial_state 0
+
+  evolve :increased do
+    state + 1
+  end
+end
+
+[:increased, :increased].reduce(decider.initial_state) { |state, event| decider.evolve(state, event) }
+#> 2
+```
+
+You can shortcut that with `&`:
+
+```ruby
+[:increased, :increased].reduce(decider.initial_state, &decider.method(:evolve))
+#> 2
+[:increased, :increased].reduce(decider.initial_state, &decider.evolve)
+#> 2
+```

examples/state.md

@@ -8,11 +8,11 @@ State = Data.define(:value)
 decider = Decider.define do
   initial_state State.new(value: 0)
 
-  decide Commands::Command do |command, state|
-    [Events::Event.new(value: command.value)]
+  decide Commands::Command do
+    emit Events::Event.new(value: command.value)
   end
 
-  evolve Events::Event do |state, event|
+  evolve Events::Event do
     state.with(value: state.value + 1)
   end
 end
@@ -24,26 +24,16 @@ end
 decider = Decider.define do
   initial_state :turned_off
 
-  decide Commands::TurnOn do |_command, state|
-    case state
-    in :turned_off
-      [Events::TurnedOn.new]
-    else
-      []
-    end
+  decide Commands::TurnOn, :turned_off do
+    emit Events::TurnedOn.new
   end
 
-  decide Commands::TurnOff do |_command, state|
-    case state
-    in :turned_on
-      [Events::TurnedOn.new]
-    else
-      []
-    end
+  decide Commands::TurnOff, :turned_on do
+    emit Events::TurnedOff.new
   end
 
-  evolve Events::TurnedOn do |_state, _event|
-    :turned_off
+  evolve Events::TurnedOn do
+    :turned_on
   end
 end
 ```
@@ -54,12 +44,12 @@ end
 decider = Decider.define do
   initial_state []
 
-  decide Commands::Command do |command, _state|
-    [Events::Event.new(value: command.value)]
+  decide Commands::Command, [] do
+    emit Events::Event.new(value: command.value)
   end
 
-  evolve Events::Event do |state, event|
-    state = state + [event]
+  evolve Events::Event do
+    state + [event]
   end
 end
 ```