Value -> Value/Event/IO-Stream

Close 12

1 files changed, 48 insertions, 0 deletions

diff --git a/core/stream/io.moon b/core/stream/io.moon
new file mode 100644
index 0000000..fcaeb9f
--- /dev/null
+++ b/core/stream/io.moon
@@ -0,0 +1,48 @@
+----
+-- Stream of external side-effects.
+--
+-- Unlike other `Stream`s, this is not updated/set by an `Op` instace, but is
+-- continuously polled for changes by the runtime and may mark itself as
+-- *dirty* at any point in time. All runtime execution happens due to IOStream
+-- updates, which ripple through the `Result` tree.
+--
+-- @classmod IOStream
+import EventStream from require 'core.stream.event'
+
+class IOStream extends EventStream
+--- IOStream interface.
+--
+-- methods that have to be implemented by `IOStream` implementations.
+-- @section interface
+
+  --- construct a new IOStream.
+  --
+  -- Must prepare the instance for `dirty` to be called.
+  -- The super-constructor should be called to set `Stream.type`.
+  --
+  -- @classmethod
+  -- @tparam string type the typename of this stream.
+  new: (type) => super type
+
+  --- poll for changes.
+  --
+  -- Called every frame by the main event loop to update internal state.
+  tick: =>
+
+  --- check whether this adapter requires processing.
+  --
+  -- Must return a boolean indicating whether `Op`s that refer to this instance
+  -- via `Input.io` should be notified (via `Op:tick`). May be called multiple
+  -- times. May be called before `tick` on the first frame after construction.
+  --
+  -- If this is not overrided, the `EventStream` interface can be used, see
+  -- `EventStream.add`, `EventStream.unwrap`, and `EventStream.dirty`.
+  --
+  -- @function dirty
+  -- @treturn bool whether processing is required
+
+  __inherited: (cls) => cls.__base.__tostring = @__tostring
+
+{
+  :IOStream
+}