Build typed IPython app execution pipeline

src/ipython_demo/models.py

@@ -0,0 +1,57 @@
+from dataclasses import dataclass
+from typing import Literal
+
+
+CallEventKind = Literal[
+    "stdout",
+    "stderr",
+    "display_data",
+    "execute_result",
+    "clear_output",
+    "update_display_data",
+    "error",
+]
+
+
+@dataclass
+class CallEvent:
+    """One ordered, UI-safe event emitted while a call executes."""
+
+    call_id: str
+    sequence: int
+    kind: CallEventKind
+    text: str | None = None
+    data: dict[str, object] | None = None
+    metadata: dict[str, object] | None = None
+    transient: dict[str, object] | None = None
+
+
+@dataclass
+class CallError:
+    """Serializable error information from one cell execution."""
+
+    ename: str
+    evalue: str
+    traceback: list[str]
+
+
+@dataclass
+class CallResult:
+    """The application-level result of one cell execution."""
+
+    call_id: str
+    execution_count: int | None
+    result: object | None
+    error: CallError | None = None
+
+
+@dataclass
+class CallResponse:
+    """Complete response envelope intended for a UI or graph node."""
+
+    call_id: str
+    shell_name: str
+    code: str
+    collapsed: bool
+    result: CallResult
+    events: list[CallEvent]