remove IOStreams, support optional polling in Ops

4 files changed, 18 insertions, 9 deletions

diff --git a/alv/base/init.moon b/alv/base/init.moon
index 586a6bd..69979a5 100644
--- a/alv/base/init.moon
+++ b/alv/base/init.moon
@@ -16,7 +16,6 @@
 -- @see Constant
 -- @see SigStream
 -- @see EvtStream
--- @see IOStream
 -- @see type.T
 -- @see type.Primitive
 -- @see type.Array
@@ -30,7 +29,7 @@ import Builtin from require 'alv.base.builtin'
 import FnDef from require 'alv.base.fndef'
 import Input from require 'alv.base.input'
 import const, sig, evt from require 'alv.base.match'
-import Constant, SigStream, EvtStream, IOStream from require 'alv.result'
+import Constant, SigStream, EvtStream from require 'alv.result'
 import T, Primitive, Array, Struct from require 'alv.type'
 import RTNode from require 'alv.rtnode'
 import Error from require 'alv.error'
@@ -45,7 +44,7 @@ import Error from require 'alv.error'
   -- redundant exports, to keep anything an extension might need in one import
 
   -- Results
-  :Constant, :SigStream, :EvtStream, :IOStream
+  :Constant, :SigStream, :EvtStream
 
   -- Types
   :T, :Primitive, :Array, :Struct
diff --git a/alv/base/input.moon b/alv/base/input.moon
index f29bd10..87e00de 100644
--- a/alv/base/input.moon
+++ b/alv/base/input.moon
@@ -2,7 +2,7 @@
 -- Update scheduling policy for `Op` arguments.
 --
 -- @classmod Input
-import Constant, SigStream, EvtStream, IOStream from require 'alv.result'
+import Constant, SigStream, EvtStream from require 'alv.result'
 import RTNode from require 'alv.rtnode'
 
 inherits = (klass, frm) ->
@@ -112,9 +112,8 @@ class Input
   -- Behaviour depends on what kind of `Result` `value` is:
   --
   -- - `Constant`: treated like `cold`.
-  -- - `SigStream`: Marked dirty only if old and new `SigStream` differ.
-  -- - `EvtStream` and `IOStream`: Marked dirty only if the current
-  --   `EvtStream` is dirty.
+  -- - `SigStream`: Marked dirty only if old and new `result` differ.
+  -- - `EvtStream`: Marked dirty only if the current `result` is dirty.
   --
   -- This is the most common `Input` strategy.
   --
@@ -152,7 +151,6 @@ mapping = {
   [Constant]: ValueInput
   [SigStream]: ValueInput
   [EvtStream]: Input
-  [IOStream]: IOInput
 }
 
 {
diff --git a/alv/base/match.moon b/alv/base/match.moon
index 4653107..f5fa99c 100644
--- a/alv/base/match.moon
+++ b/alv/base/match.moon
@@ -295,7 +295,7 @@ sig = setmetatable {}, {
   __call: (...) => Type '~', ...
 }
 
---- `Type` shorthands for matching `EvtStream` and `IOStream`s.
+--- `Type` shorthands for matching `EvtStream`s.
 --
 -- Call or index with a string to obtain an `Type` instance.
 -- Call to obtain a wildcard pattern.
diff --git a/alv/base/op.moon b/alv/base/op.moon
index f20518d..bb48b09 100644
--- a/alv/base/op.moon
+++ b/alv/base/op.moon
@@ -112,6 +112,18 @@ class Op
     else
       {}
 
+  --- poll for external changes (optional).
+  --
+  -- If implemented, this method will be called at a high frequency and should
+  -- return `true` whenever processing is required due to an external event or
+  -- condition. After polling all such IO Ops a new tick will be executed if any
+  -- returned true. The implementation of `poll` is responsible for triggering
+  -- the `tick` method by writing to an internally allocated `Result` that has
+  -- been inserted into `inputs`.
+  --
+  -- @function poll
+  -- @treturn ?boolean dirty whether processing is required
+
 --- implementation utilities.
 --
 -- super-methods and utilities for use by implementations.