Commandline improvements

* @FILE arguments
 * -s:filename searches relative to the configuration path

this makes it easier to create whole preset configurations

README.md

@@ -81,6 +81,31 @@ Put your OpenAI API key in the platform configuration directory for chap, e.g.,
 
  * `chap grep needle`
 
+## `@FILE` arguments
+
+It's useful to set a bunch of related arguments together, for instance to fully
+configure a back-end. This functionality is implemented via `@FILE` arguments.
+
+Before any other command-line argument parsing is performed, `@FILE` arguments are expanded:
+
+ * An `@FILE` argument is searched relative to the current directory
+ * An `@:FILE` argument is searched relative to the configuration directory (e.g., $HOME/.config/chap)
+ * If an argument starts with a literal `@`, double it: `@@`
+ * `@.` stops processing any further `@FILE` arguments and leaves them unchanged.
+The contents of an `@FILE` are parsed according to `shlex.split(comments=True)`.
+Comments are not supported.
+A typical content might look like this:
+```
+# gpt-3.5.txt: Use cheaper gpt 3.5 and custom prompt
+--backend openai-chatgpt
+-B model:gpt-3.5-turbo
+-s my-custom-system-message.txt
+```
+and you might use it with
+```
+chap @:gpt-3.5.txt ask what version of gpt is this
+```
+
 ## Interactive terminal usage
 The interactive terminal mode is accessed via `chap tui`.
 

src/chap/core.py

@@ -11,6 +11,7 @@ import os
 import pathlib
 import pkgutil
 import subprocess
+import shlex
 from dataclasses import MISSING, Field, dataclass, fields
 from typing import (
     Any,
@@ -40,6 +41,7 @@ else:
 
 conversations_path = platformdirs.user_state_path("chap") / "conversations"
 conversations_path.mkdir(parents=True, exist_ok=True)
+configuration_path = platformdirs.user_config_path("chap")
 
 
 class ABackend(Protocol):
@@ -333,6 +335,33 @@ class Obj:
     session_filename: Optional[pathlib.Path] = None
 
 
+def expand_splats(args):
+    result = []
+    saw_at_dot = False
+    for a in args:
+        if a == "@.":
+            saw_at_dot = True
+            continue
+        if saw_at_dot:
+            result.append(a)
+            continue
+        if a.startswith("@@"):  ## double @ to escape an argument that starts with @
+            result.append(a[1:])
+            continue
+        if not a.startswith("@"):
+            result.append(a)
+            continue
+        if a.startswith("@:"):
+            fn = configuration_path / a[2:]
+        else:
+            fn = a[1:]
+        with open(fn, "r", encoding="utf-8") as f:
+            content = f.read()
+        parts = shlex.split(content)
+        result.extend(expand_splats(parts))
+    return result
+
+
 class MyCLI(click.Group):
     def make_context(
         self,
@@ -370,6 +399,25 @@ class MyCLI(click.Group):
         if hasattr(api, "parameters"):
             format_backend_help(api, formatter)
 
+    def main(self, args=None, windows_expand_args=True, **kw):
+        if args is None:
+            args = sys.argv[1:]
+            if os.name == "nt" and windows_expand_args:
+                args = click.utils._expand_args(args)
+        else:
+            args = list(args)
+
+        args = expand_splats(args)
+
+        super().main(args, **kw)
+
+
+class ConfigRelativeFile(click.File):
+    def convert(self, value, param, ctx):
+        if isinstance(value, str) and value.startswith(":"):
+            value = configuration_path / value[1:]
+        return super().convert(value, param, ctx)
+
 
 main = MyCLI(
     help="Commandline interface to ChatGPT",
@@ -382,11 +430,12 @@ main = MyCLI(
             callback=version_callback,
         ),
         click.Option(
-            ("--system-message-file", "-@"),
-            type=click.File("r"),
+            ("--system-message-file", "-s"),
+            type=ConfigRelativeFile("r"),
             default=None,
             callback=set_system_message_from_file,
             expose_value=False,
+            help=f"Set the system message from a file. If the filename starts with `:` it is relative to the configuration path {configuration_path}.",
         ),
         click.Option(
             ("--system-message", "-S"),