Merge pull request #30 from jepler/multiline2

Switch chap tui to a multiline text field

.gitignore

@@ -8,3 +8,4 @@ __pycache__
 /dist
 /src/chap/__version__.py
 /venv
+/keys.log

.pre-commit-config.yaml

@@ -6,12 +6,8 @@ default_language_version:
   python: python3
 
 repos:
-- repo: https://github.com/psf/black
-  rev: 23.1.0
-  hooks:
-  - id: black
 - repo: https://github.com/pre-commit/pre-commit-hooks
-  rev: v4.4.0
+  rev: v4.5.0
   hooks:
   -   id: check-yaml
   -   id: end-of-file-fixer
@@ -19,23 +15,20 @@ repos:
   -   id: trailing-whitespace
       exclude: tests
 -   repo: https://github.com/codespell-project/codespell
-    rev: v2.2.4
+    rev: v2.2.6
     hooks:
     -   id: codespell
         args: [-w]
 - repo: https://github.com/fsfe/reuse-tool
-  rev: v1.1.2
+  rev: v2.1.0
   hooks:
   - id: reuse
-- repo: https://github.com/pycqa/isort
+- repo: https://github.com/astral-sh/ruff-pre-commit
-  rev: 5.12.0
+  # Ruff version.
+  rev: v0.1.6
   hooks:
-    - id: isort
+    # Run the linter.
-      name: isort (python)
+    - id: ruff
-      args: ['--profile', 'black']
+      args: [ --fix, --preview ]
-- repo: https://github.com/pycqa/pylint
+    # Run the formatter.
-  rev: v2.17.0
+    - id: ruff-format
-  hooks:
-  - id: pylint
-    additional_dependencies: [click,httpx,lorem-text,simple-parsing,'textual>=0.18.0',tiktoken,websockets]
-    args: ['--source-roots', 'src']

.pylintrc

@@ -1,12 +0,0 @@
-# SPDX-FileCopyrightText: 2023 Jeff Epler <jepler@gmail.com>
-#
-# SPDX-License-Identifier: MIT
-
-[MESSAGES CONTROL]
-disable=
-    duplicate-code,
-    invalid-name,
-    line-too-long,
-    missing-class-docstring,
-    missing-function-docstring,
-    missing-module-docstring,

README.md

@@ -9,11 +9,11 @@ SPDX-License-Identifier: MIT
 
 # chap - A Python interface to chatgpt and other LLMs, including a terminal user interface (tui)
 
-![Chap screencast](https://github.com/jepler/chap/blob/main/chap.gif)
+![Chap screencast](https://raw.githubusercontent.com/jepler/chap/main/chap.gif)
 
 ## System requirements
 
-Chap is developed on Linux with Python 3.11. Due to use of the `X | Y` style of type hints, it is known to not work on Python 3.9 and older. The target minimum Python version is 3.11 (debian stable).
+Chap is primarily developed on Linux with Python 3.11. Moderate effort will be made to support versions back to Python 3.9 (Debian oldstable).
 
 ## Installation
 
@@ -82,7 +82,28 @@ Put your OpenAI API key in the platform configuration directory for chap, e.g.,
  * `chap grep needle`
 
 ## Interactive terminal usage
- * `chap tui`
+The interactive terminal mode is accessed via `chap tui`.
+
+There are a variety of keyboard shortcuts to be aware of:
+ * tab/shift-tab to move between the entry field and the conversation, or between conversation items
+ * While in the text box, F9 or (if supported by your terminal) alt+enter to submit multiline text
+ * while on a conversation item:
+   * ctrl+x to re-draft the message. This
+     * saves a copy of the session in an auto-named file in the conversations folder
+     * removes the conversation from this message to the end
+     * puts the user's message in the text box to edit
+   * ctrl+x to re-submit the message. This
+     * saves a copy of the session in an auto-named file in the conversations folder
+     * removes the conversation from this message to the end
+     * puts the user's message in the text box
+     * and submits it immediately
+   * ctrl+y to yank the message. This places the response part of the current
+     interaction in the operating system clipboard to be pasted (e..g, with
+     ctrl+v or command+v in other software)
+   * ctrl+q to toggle whether this message may be included in the contextual history for a future query.
+     The exact way history is submitted is determined by the back-end, often by
+     counting messages or tokens, but the ctrl+q toggle ensures this message (both the user
+     and assistant message parts) are not considered.
 
 ## Sessions & Command-line Parameters
 

chap-dev.py

@@ -14,7 +14,6 @@ src_path = project_root / "src"
 sys.path.insert(0, str(src_path))
 
 if __name__ == "__main__":
-    # pylint: disable=import-error,no-name-in-module
     from chap.core import main
 
     main()

pyproject.toml

@@ -20,13 +20,14 @@ name="chap"
 authors = [{name = "Jeff Epler", email = "jepler@gmail.com"}]
 description = "Interact with the OpenAI ChatGPT API (and other text generators)"
 dynamic = ["readme","version","dependencies"]
-requires-python = ">=3.10"
+requires-python = ">=3.9"
 keywords = ["llm", "tui", "chatgpt"]
 classifiers = [
     "Development Status :: 3 - Alpha",
     "License :: OSI Approved :: MIT License",
     "Operating System :: OS Independent",
     "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",

requirements.txt

@@ -6,7 +6,8 @@ click
 httpx
 lorem-text
 platformdirs
+pyperclip
 simple_parsing
-textual>=0.18.0
+textual[syntax]
 tiktoken
 websockets

src/chap/backends/huggingface.py

@@ -89,9 +89,7 @@ A dialog, where USER interacts with AI. AI is helpful, kind, obedient, honest, a
         *,
         max_query_size: int = 5,
         timeout: float = 180,
-    ) -> AsyncGenerator[
+    ) -> AsyncGenerator[str, None]:
-        str, None
-    ]:  # pylint: disable=unused-argument,too-many-locals,too-many-branches
         new_content: list[str] = []
         inputs = self.make_full_query(session + [User(query)], max_query_size)
         try:

src/chap/backends/llama_cpp.py

@@ -55,9 +55,7 @@ A dialog, where USER interacts with AI. AI is helpful, kind, obedient, honest, a
         *,
         max_query_size: int = 5,
         timeout: float = 180,
-    ) -> AsyncGenerator[
+    ) -> AsyncGenerator[str, None]:
-        str, None
-    ]:  # pylint: disable=unused-argument,too-many-locals,too-many-branches
         params = {
             "prompt": self.make_full_query(session + [User(query)], max_query_size),
             "stream": True,

src/chap/backends/lorem.py

@@ -45,7 +45,7 @@ class Lorem:
         session: Session,
         query: str,
     ) -> AsyncGenerator[str, None]:
-        data = self.ask(session, query)[-1]
+        data = self.ask(session, query)
         for word, opt_sep in ipartition(data):
             yield word + opt_sep
             await asyncio.sleep(
@@ -56,7 +56,7 @@ class Lorem:
         self,
         session: Session,
         query: str,
-    ) -> str:  # pylint: disable=unused-argument
+    ) -> str:
         new_content = cast(
             str,
             lorem.paragraphs(

src/chap/backends/openai_chatgpt.py

@@ -101,7 +101,7 @@ class ChatGPT:
             json={
                 "model": self.parameters.model,
                 "messages": session_to_list(full_prompt),
-            },  # pylint: disable=no-member
+            },
             headers={
                 "Authorization": f"Bearer {self.get_key()}",
             },

src/chap/backends/textgen.py

@@ -29,7 +29,7 @@ USER: Hello, AI.
 
 AI: Hello! How can I assist you today?"""
 
-    async def aask(  # pylint: disable=unused-argument,too-many-locals,too-many-branches
+    async def aask(
         self,
         session: Session,
         query: str,
@@ -60,12 +60,11 @@ AI: Hello! How can I assist you today?"""
         }
         full_prompt = session + [User(query)]
         del full_prompt[1:-max_query_size]
-        new_data = old_data = full_query = (
+        new_data = old_data = full_query = "\n".join(
-            "\n".join(f"{role_map.get(q.role,'')}{q.content}\n" for q in full_prompt)
+            f"{role_map.get(q.role,'')}{q.content}\n" for q in full_prompt
-            + f"\n{role_map.get('assistant')}"
+        ) + f"\n{role_map.get('assistant')}"
-        )
         try:
-            async with websockets.connect(  # pylint: disable=no-member
+            async with websockets.connect(
                 f"ws://{self.parameters.server_hostname}:7860/queue/join"
             ) as websocket:
                 while content := json.loads(await websocket.recv()):
@@ -127,7 +126,7 @@ AI: Hello! How can I assist you today?"""
                         #  stop generation by closing the websocket here
                         if content["msg"] == "process_completed":
                             break
-        except Exception as e:  # pylint: disable=broad-exception-caught
+        except Exception as e:
             content = f"\nException: {e!r}"
             new_data += content
             yield content

src/chap/commands/ask.py

@@ -4,7 +4,7 @@
 
 import asyncio
 import sys
-from typing import Iterable, Protocol
+from typing import Iterable, Optional, Protocol
 
 import click
 import rich
@@ -40,7 +40,7 @@ class DumbPrinter:
 
 
 class WrappingPrinter:
-    def __init__(self, width: int | None = None) -> None:
+    def __init__(self, width: Optional[int] = None) -> None:
         self._width = width or rich.get_console().width
         self._column = 0
         self._line = ""
@@ -122,4 +122,4 @@ def main(obj: Obj, prompt: str, print_prompt: bool) -> None:
 
 
 if __name__ == "__main__":
-    main()  # pylint: disable=no-value-for-parameter
+    main()

src/chap/commands/cat.py

@@ -38,4 +38,4 @@ def main(obj: Obj, no_system: bool) -> None:
 
 
 if __name__ == "__main__":
-    main()  # pylint: disable=no-value-for-parameter
+    main()

src/chap/commands/grep.py

@@ -24,8 +24,8 @@ def list_files_matching_rx(
         "*.json"
     ):
         try:
-            session = session_from_file(conversation)  # pylint: disable=no-member
+            session = session_from_file(conversation)
-        except Exception as e:  # pylint: disable=broad-exception-caught
+        except Exception as e:
             print(f"Failed to read {conversation}: {e}", file=sys.stderr)
             continue
 
@@ -67,4 +67,4 @@ def main(
 
 
 if __name__ == "__main__":
-    main()  # pylint: disable=no-value-for-parameter
+    main()

src/chap/commands/import.py

@@ -82,4 +82,4 @@ def main(output_directory: pathlib.Path, files: list[TextIO]) -> None:
 
 
 if __name__ == "__main__":
-    main()  # pylint: disable=no-value-for-parameter
+    main()

src/chap/commands/render.py

@@ -45,4 +45,4 @@ def main(obj: Obj, no_system: bool) -> None:
 
 
 if __name__ == "__main__":
-    main()  # pylint: disable=no-value-for-parameter
+    main()

src/chap/commands/tui.css

@@ -54,3 +54,5 @@ Input {
 Markdown {
     margin: 0 1 0 0;
 }
+
+SubmittableTextArea { height: 3 }

src/chap/commands/tui.py

@@ -3,30 +3,53 @@
 # SPDX-License-Identifier: MIT
 
 import asyncio
-import subprocess
 import sys
-from typing import cast
+from typing import Any, Optional, cast, TYPE_CHECKING
 
+import click
 from markdown_it import MarkdownIt
 from textual import work
+from textual._ansi_sequences import ANSI_SEQUENCES_KEYS
 from textual.app import App, ComposeResult
 from textual.binding import Binding
 from textual.containers import Container, Horizontal, VerticalScroll
-from textual.widgets import Button, Footer, Input, LoadingIndicator, Markdown
+from textual.keys import Keys
+from textual.widgets import Button, Footer, LoadingIndicator, Markdown, TextArea
 
 from ..core import Backend, Obj, command_uses_new_session, get_api, new_session_path
 from ..session import Assistant, Message, Session, User, new_session, session_to_file
 
 
+# workaround for pyperclip being un-typed
+if TYPE_CHECKING:
+
+    def pyperclip_copy(data: str) -> None:
+        ...
+else:
+    from pyperclip import copy as pyperclip_copy
+
+
+# Monkeypatch alt+enter as meaning "F9", WFM
+# ignore typing here because ANSI_SEQUENCES_KEYS is a Mapping[] which is read-only as
+# far as mypy is concerned.
+ANSI_SEQUENCES_KEYS["\x1b\r"] = (Keys.F9,)  # type: ignore
+ANSI_SEQUENCES_KEYS["\x1b\n"] = (Keys.F9,)  # type: ignore
+
+
+class SubmittableTextArea(TextArea):
+    BINDINGS = [
+        Binding("f9", "submit", "Submit", show=True),
+        Binding("tab", "focus_next", show=False, priority=True),  # no inserting tabs
+    ]
+
+
 def parser_factory() -> MarkdownIt:
     parser = MarkdownIt()
     parser.options["html"] = False
     return parser
 
 
-class ChapMarkdown(
+class ChapMarkdown(Markdown, can_focus=True, can_focus_children=False):
-    Markdown, can_focus=True, can_focus_children=False
-):  # pylint: disable=function-redefined
     BINDINGS = [
         Binding("ctrl+y", "yank", "Yank text", show=True),
         Binding("ctrl+r", "resubmit", "resubmit", show=True),
@@ -56,10 +79,10 @@ class Tui(App[None]):
     ]
 
     def __init__(
-        self, api: Backend | None = None, session: Session | None = None
+        self, api: Optional[Backend] = None, session: Optional[Session] = None
     ) -> None:
         super().__init__()
-        self.api = api or get_api("lorem")
+        self.api = api or get_api(click.Context(click.Command("chap tui")), "lorem")
         self.session = (
             new_session(self.api.system_message) if session is None else session
         )
@@ -73,8 +96,8 @@ class Tui(App[None]):
         return cast(VerticalScroll, self.query_one("#wait"))
 
     @property
-    def input(self) -> Input:
+    def input(self) -> SubmittableTextArea:
-        return self.query_one(Input)
+        return self.query_one(SubmittableTextArea)
 
     @property
     def cancel_button(self) -> CancelButton:
@@ -94,7 +117,9 @@ class Tui(App[None]):
             Container(id="pad"),
             id="content",
         )
-        yield Input(placeholder="Prompt")
+        s = SubmittableTextArea(language="markdown")
+        s.show_line_numbers = False
+        yield s
         with Horizontal(id="wait"):
             yield LoadingIndicator()
             yield CancelButton(label="❌ Stop Generation", id="cancel", disabled=True)
@@ -103,8 +128,8 @@ class Tui(App[None]):
         self.container.scroll_end(animate=False)
         self.input.focus()
 
-    async def on_input_submitted(self, event: Input.Submitted) -> None:
+    async def action_submit(self) -> None:
-        self.get_completion(event.value)
+        self.get_completion(self.input.text)
 
     @work(exclusive=True)
     async def get_completion(self, query: str) -> None:
@@ -162,10 +187,10 @@ class Tui(App[None]):
         try:
             await asyncio.gather(render_fun(), get_token_fun())
         finally:
-            self.input.value = ""
+            self.input.clear()
             all_output = self.session[-1].content
             output.update(all_output)
-            output._markdown = all_output  # pylint: disable=protected-access
+            output._markdown = all_output
             self.container.scroll_end()
 
             for markdown in self.container.children:
@@ -183,8 +208,8 @@ class Tui(App[None]):
     def action_yank(self) -> None:
         widget = self.focused
         if isinstance(widget, ChapMarkdown):
-            content = widget._markdown or ""  # pylint: disable=protected-access
+            content = widget._markdown or ""
-            subprocess.run(["xsel", "-ib"], input=content.encode("utf-8"), check=False)
+            pyperclip_copy(content)
 
     def action_toggle_history(self) -> None:
         widget = self.focused
@@ -204,9 +229,7 @@ class Tui(App[None]):
     async def action_stop_generating(self) -> None:
         self.workers.cancel_all()
 
-    async def on_button_pressed(  # pylint: disable=unused-argument
+    async def on_button_pressed(self, event: Button.Pressed) -> None:
-        self, event: Button.Pressed
-    ) -> None:
         self.workers.cancel_all()
 
     async def action_quit(self) -> None:
@@ -235,19 +258,31 @@ class Tui(App[None]):
         session_to_file(self.session, new_session_path())
 
         query = self.session[idx].content
-        self.input.value = query
+        self.input.load_text(query)
 
         del self.session[idx:]
         for child in self.container.children[idx:-1]:
             await child.remove()
 
         self.input.focus()
+        self.on_text_area_changed()
         if resubmit:
-            await self.input.action_submit()
+            await self.action_submit()
+
+    def on_text_area_changed(self, event: Any = None) -> None:
+        height = self.input.document.get_size(self.input.indent_width)[1]
+        max_height = max(3, self.size.height - 6)
+        if height >= max_height:
+            self.input.styles.height = max_height
+        elif height <= 3:
+            self.input.styles.height = 3
+        else:
+            self.input.styles.height = height
 
 
 @command_uses_new_session
-def main(obj: Obj) -> None:
+@click.option("--replace-system-prompt/--no-replace-system-prompt", default=False)
+def main(obj: Obj, replace_system_prompt: bool) -> None:
     """Start interactive terminal user interface session"""
     api = obj.api
     assert api is not None
@@ -256,6 +291,9 @@ def main(obj: Obj) -> None:
     session_filename = obj.session_filename
     assert session_filename is not None
 
+    if replace_system_prompt:
+        session[0].content = obj.system_message or api.system_message
+
     tui = Tui(api, session)
     tui.run()
 
@@ -268,4 +306,4 @@ def main(obj: Obj) -> None:
 
 
 if __name__ == "__main__":
-    main()  # pylint: disable=no-value-for-parameter
+    main()

src/chap/core.py

@@ -1,7 +1,7 @@
 # SPDX-FileCopyrightText: 2023 Jeff Epler <jepler@gmail.com>
 #
 # SPDX-License-Identifier: MIT
-# pylint: disable=import-outside-toplevel
+
 
 import asyncio
 import datetime
@@ -10,23 +10,38 @@ import os
 import pathlib
 import pkgutil
 import subprocess
-from dataclasses import MISSING, dataclass, fields
+from dataclasses import MISSING, Field, dataclass, fields
-from types import UnionType
+from typing import (
-from typing import Any, AsyncGenerator, Callable, cast
+    Any,
+    AsyncGenerator,
+    Callable,
+    Optional,
+    Union,
+    cast,
+    get_origin,
+    get_args,
+)
+import sys
 
 import click
 import platformdirs
 from simple_parsing.docstring import get_attribute_docstring
 from typing_extensions import Protocol
 
-from . import backends, commands  # pylint: disable=no-name-in-module
+from . import backends, commands
 from .session import Message, Session, System, session_from_file
 
+UnionType: type
+if sys.version_info >= (3, 10):
+    from types import UnionType
+else:
+    UnionType = type(Union[int, float])
+
 conversations_path = platformdirs.user_state_path("chap") / "conversations"
 conversations_path.mkdir(parents=True, exist_ok=True)
 
 
-class ABackend(Protocol):  # pylint: disable=too-few-public-methods
+class ABackend(Protocol):
     def aask(self, session: Session, query: str) -> AsyncGenerator[str, None]:
         """Make a query, updating the session with the query and response, returning the query token by token"""
 
@@ -39,7 +54,7 @@ class Backend(ABackend, Protocol):
         """Make a query, updating the session with the query and response, returning the query"""
 
 
-class AutoAskMixin:  # pylint: disable=too-few-public-methods
+class AutoAskMixin:
     """Mixin class for backends implementing aask"""
 
     def ask(self, session: Session, query: str) -> str:
@@ -54,20 +69,50 @@ class AutoAskMixin:  # pylint: disable=too-few-public-methods
         return "".join(tokens)
 
 
-def last_session_path() -> pathlib.Path | None:
+def last_session_path() -> Optional[pathlib.Path]:
     result = max(
         conversations_path.glob("*.json"), key=lambda p: p.stat().st_mtime, default=None
     )
     return result
 
 
-def new_session_path(opt_path: pathlib.Path | None = None) -> pathlib.Path:
+def new_session_path(opt_path: Optional[pathlib.Path] = None) -> pathlib.Path:
     return opt_path or conversations_path / (
         datetime.datetime.now().isoformat().replace(":", "_") + ".json"
     )
 
 
-def configure_api_from_environment(api_name: str, api: Backend) -> None:
+def get_field_type(field: Field[Any]) -> Any:
+    field_type = field.type
+    if isinstance(field_type, str):
+        raise RuntimeError(
+            "parameters dataclass may not use 'from __future__ import annotations"
+        )
+    origin = get_origin(field_type)
+    if origin in (Union, UnionType):
+        for arg in get_args(field_type):
+            if arg is not None:
+                return arg
+    return field_type
+
+
+def convert_str_to_field(ctx: click.Context, field: Field[Any], value: str) -> Any:
+    field_type = get_field_type(field)
+    try:
+        if field_type is bool:
+            tv = click.types.BoolParamType().convert(value, None, ctx)
+        else:
+            tv = field_type(value)
+        return tv
+    except ValueError as e:
+        raise click.BadParameter(
+            f"Invalid value for {field.name} with value {value}: {e}"
+        ) from e
+
+
+def configure_api_from_environment(
+    ctx: click.Context, api_name: str, api: Backend
+) -> None:
     if not hasattr(api, "parameters"):
         return
 
@@ -76,26 +121,21 @@ def configure_api_from_environment(api_name: str, api: Backend) -> None:
         value = os.environ.get(envvar)
         if value is None:
             continue
-        try:
+        tv = convert_str_to_field(ctx, field, value)
-            tv = field.type(value)
-        except ValueError as e:
-            raise click.BadParameter(
-                f"Invalid value for {field.name} with value {value}: {e}"
-            ) from e
         setattr(api.parameters, field.name, tv)
 
 
-def get_api(name: str = "openai_chatgpt") -> Backend:
+def get_api(ctx: click.Context, name: str = "openai_chatgpt") -> Backend:
     name = name.replace("-", "_")
-    result = cast(
+    backend = cast(
         Backend, importlib.import_module(f"{__package__}.backends.{name}").factory()
     )
-    configure_api_from_environment(name, result)
+    configure_api_from_environment(ctx, name, backend)
-    return result
+    return backend
 
 
 def do_session_continue(
-    ctx: click.Context, param: click.Parameter, value: pathlib.Path | None
+    ctx: click.Context, param: click.Parameter, value: Optional[pathlib.Path]
 ) -> None:
     if value is None:
         return
@@ -108,9 +148,7 @@ def do_session_continue(
     ctx.obj.session_filename = value
 
 
-def do_session_last(
+def do_session_last(ctx: click.Context, param: click.Parameter, value: bool) -> None:
-    ctx: click.Context, param: click.Parameter, value: bool
-) -> None:  # pylint: disable=unused-argument
     if not value:
         return
     do_session_continue(ctx, param, last_session_path())
@@ -138,18 +176,14 @@ def colonstr(arg: str) -> tuple[str, str]:
     return cast(tuple[str, str], tuple(arg.split(":", 1)))
 
 
-def set_system_message(  # pylint: disable=unused-argument
+def set_system_message(ctx: click.Context, param: click.Parameter, value: str) -> None:
-    ctx: click.Context, param: click.Parameter, value: str
-) -> None:
     if value and value.startswith("@"):
         with open(value[1:], "r", encoding="utf-8") as f:
             value = f.read().rstrip()
     ctx.obj.system_message = value
 
 
-def set_backend(  # pylint: disable=unused-argument
+def set_backend(ctx: click.Context, param: click.Parameter, value: str) -> None:
-    ctx: click.Context, param: click.Parameter, value: str
-) -> None:
     if value == "list":
         formatter = ctx.make_formatter()
         format_backend_list(formatter)
@@ -157,7 +191,7 @@ def set_backend(  # pylint: disable=unused-argument
         ctx.exit()
 
     try:
-        ctx.obj.api = get_api(value)
+        ctx.obj.api = get_api(ctx, value)
     except ModuleNotFoundError as e:
         raise click.BadParameter(str(e))
 
@@ -172,15 +206,13 @@ def format_backend_help(api: Backend, formatter: click.HelpFormatter) -> None:
             if doc:
                 doc += " "
             doc += f"(Default: {default!r})"
-            f_type = f.type
+            f_type = get_field_type(f)
-            if isinstance(f_type, UnionType):
-                f_type = f_type.__args__[0]
             typename = f_type.__name__
             rows.append((f"-B {name}:{typename.upper()}", doc))
         formatter.write_dl(rows)
 
 
-def set_backend_option(  # pylint: disable=unused-argument
+def set_backend_option(
     ctx: click.Context, param: click.Parameter, opts: list[tuple[str, str]]
 ) -> None:
     api = ctx.obj.api
@@ -195,16 +227,8 @@ def set_backend_option(  # pylint: disable=unused-argument
         field = all_fields.get(name)
         if field is None:
             raise click.BadParameter(f"Invalid parameter {name}")
-        f_type = field.type
+        tv = convert_str_to_field(ctx, field, value)
-        if isinstance(f_type, UnionType):
+        setattr(api.parameters, field.name, tv)
-            f_type = f_type.__args__[0]
-        try:
-            tv = f_type(value)
-        except ValueError as e:
-            raise click.BadParameter(
-                f"Invalid value for {name} with value {value}: {e}"
-            ) from e
-        setattr(api.parameters, name, tv)
 
     for kv in opts:
         set_one_backend_option(kv)
@@ -264,9 +288,7 @@ def command_uses_new_session(f_in: click.decorators.FC) -> click.Command:
     return click.command()(f)
 
 
-def version_callback(  # pylint: disable=unused-argument
+def version_callback(ctx: click.Context, param: click.Parameter, value: None) -> None:
-    ctx: click.Context, param: click.Parameter, value: None
-) -> None:
     if not value or ctx.resilient_parsing:
         return
 
@@ -293,18 +315,18 @@ def version_callback(  # pylint: disable=unused-argument
 
 @dataclass
 class Obj:
-    api: Backend | None = None
+    api: Optional[Backend] = None
-    system_message: str | None = None
+    system_message: Optional[str] = None
-    session: list[Message] | None = None
+    session: Optional[list[Message]] = None
-    session_filename: pathlib.Path | None = None
+    session_filename: Optional[pathlib.Path] = None
 
 
 class MyCLI(click.MultiCommand):
     def make_context(
         self,
-        info_name: str | None,
+        info_name: Optional[str],
         args: list[str],
-        parent: click.Context | None = None,
+        parent: Optional[click.Context] = None,
         **extra: Any,
     ) -> click.Context:
         result = super().make_context(info_name, args, parent, obj=Obj(), **extra)
@@ -332,7 +354,7 @@ class MyCLI(click.MultiCommand):
         self, ctx: click.Context, formatter: click.HelpFormatter
     ) -> None:
         super().format_options(ctx, formatter)
-        api = ctx.obj.api or get_api()
+        api = ctx.obj.api or get_api(ctx)
         if hasattr(api, "parameters"):
             format_backend_help(api, formatter)
 

src/chap/session.py

@@ -7,13 +7,13 @@ from __future__ import annotations
 import json
 import pathlib
 from dataclasses import asdict, dataclass
-from typing import cast
+from typing import Union, cast
 
 from typing_extensions import TypedDict
 
 
 # not an enum.Enum because these objects are not json-serializable, sigh
-class Role:  # pylint: disable=too-few-public-methods
+class Role:
     ASSISTANT = "assistant"
     SYSTEM = "system"
     USER = "user"
@@ -65,11 +65,11 @@ def session_from_json(data: str) -> Session:
     return [Message(**mapping) for mapping in j]
 
 
-def session_from_file(path: pathlib.Path | str) -> Session:
+def session_from_file(path: Union[pathlib.Path, str]) -> Session:
     with open(path, "r", encoding="utf-8") as f:
         return session_from_json(f.read())
 
 
-def session_to_file(session: Session, path: pathlib.Path | str) -> None:
+def session_to_file(session: Session, path: Union[pathlib.Path, str]) -> None:
     with open(path, "w", encoding="utf-8") as f:
         f.write(session_to_json(session))