Build typed IPython app execution pipeline

src/ipython_demo/events.py

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+import traceback as traceback_module
+
+from IPython.core.history import HistoryOutput
+from IPython.core.interactiveshell import ExecutionResult
+
+from .models import CallError, CallEvent
+
+
+def event_from_history_output(
+    output: HistoryOutput,
+    *,
+    call_id: str,
+    sequence: int,
+) -> CallEvent | None:
+    """Convert one IPython ``HistoryOutput`` into the event model."""
+    if output.output_type == "out_stream":
+        return CallEvent(
+            call_id=call_id,
+            sequence=sequence,
+            kind="stdout",
+            text="".join(output.bundle.get("stream", [])),
+        )
+
+    if output.output_type == "err_stream":
+        return CallEvent(
+            call_id=call_id,
+            sequence=sequence,
+            kind="stderr",
+            text="".join(output.bundle.get("stream", [])),
+        )
+
+    if output.output_type in {"display_data", "execute_result"}:
+        return CallEvent(
+            call_id=call_id,
+            sequence=sequence,
+            kind=output.output_type,
+            data=dict(output.bundle),
+        )
+
+    return None
+
+
+def error_from_execution_result(
+    execution: ExecutionResult,
+) -> CallError | None:
+    """Convert an IPython execution error into the application model."""
+    error = execution.error_before_exec or execution.error_in_exec
+    if error is None:
+        return None
+
+    return CallError(
+        ename=type(error).__name__,
+        evalue=str(error),
+        traceback=traceback_module.format_exception(error),
+    )
+
+
+def event_from_execution_result(
+    execution: ExecutionResult,
+    *,
+    call_id: str,
+    sequence: int,
+) -> CallEvent | None:
+    """Convert an IPython execution error into an ``error`` event."""
+    error = error_from_execution_result(execution)
+    if error is None:
+        return None
+
+    return CallEvent(
+        call_id=call_id,
+        sequence=sequence,
+        kind="error",
+        text=error.evalue,
+        data={
+            "ename": error.ename,
+            "evalue": error.evalue,
+            "traceback": error.traceback,
+        },
+    )