WIP: stdio stream errors

Author: lann

wit-0.3.0-draft/stdio.wit

@@ -1,17 +1,25 @@
+@since(version = 0.3.0-rc-2025-08-15)
+interface stdio {
+  @since(version = 0.3.0-rc-2025-08-15)
+  enum error-code {
+    // TBD - some subset of wasi:filesystem/types.error-code
+  }
+}
+
 @since(version = 0.3.0-rc-2025-08-15)
 interface stdin {
   @since(version = 0.3.0-rc-2025-08-15)
-  get-stdin: func() -> stream<u8>;
+  read-stdin: async func() -> tuple<stream<u8>, future<result<_, error-code>>>;
 }
 
 @since(version = 0.3.0-rc-2025-08-15)
 interface stdout {
   @since(version = 0.3.0-rc-2025-08-15)
-  set-stdout: func(data: stream<u8>);
+  append-stdout: async func(data: stream<u8>) -> result<_, error-code>;
 }
 
 @since(version = 0.3.0-rc-2025-08-15)
 interface stderr {
   @since(version = 0.3.0-rc-2025-08-15)
-  set-stderr: func(data: stream<u8>);
+  append-stderr: async func(data: stream<u8>) -> result<_, error-code>;
 }