sqlite-utils insert --code option, closes #684

docs/cli.rst

@@ -1561,6 +1561,27 @@ The result looks like this:
     COMMIT;
 
 
+.. _cli_insert_code:
+
+Inserting rows generated by Python code
+=======================================
+
+Instead of providing a ``FILE`` to import, you can use the ``--code`` option to pass a block of Python code that generates the rows to insert. This is the command-line equivalent of calling ``db["creatures"].insert_all(rows())`` from the :ref:`Python API <python_api>`.
+
+Your code should define either a ``rows()`` function that returns or yields dictionaries, or a ``rows`` iterable such as a list of dictionaries:
+
+.. code-block:: bash
+
+    sqlite-utils insert data.db creatures --code '
+    def rows():
+        yield {"id": 1, "name": "Cleo"}
+        yield {"id": 2, "name": "Suna"}
+    ' --pk id
+
+``--code`` can also be given a path to a Python ``.py`` file.
+
+The ``--code`` option works with both ``sqlite-utils insert`` and ``sqlite-utils upsert``, and composes with table options such as ``--pk``, ``--replace``, ``--alter``, ``--not-null`` and ``--default``. It cannot be combined with a ``FILE`` argument or with input format options such as ``--csv`` or ``--convert``.
+
 .. _cli_insert_replace:
 
 Insert-replacing data