llm --python-tools CODE option, inspired by sqlite-utils --functions

[simonw]

I'm also going to support a --python-tools option that takes a string of code - similar to how --functions works in sqlite-utils: https://sqlite-utils.datasette.io/en/stable/cli.html#defining-custom-sql-functions

sqlite-utils query sites.db "select url, domain(url) from urls" --functions '
from urllib.parse import urlparse

def domain(url):
    return urlparse(url).netloc
'

Any Python function without a _ prefix will be registered as a tool for that execution of the command.

Later on I'll probably add python_tools: YAML keys to templates.

Originally posted by @simonw in #990

I'll borrow code from https://github.com/simonw/sqlite-utils/blob/094b010fd870e9fe9f020d4df200d4de7f27209b/sqlite_utils/cli.py#L3277

[simonw]

I'm going to add that --python-tools option to the new llm tools command from #994 too as a debugging aid.

[simonw]

Got this working:

llm --python-tools 'def reverse(s): return s[::-1]' 'reverse eantuhontaehu'

Tool call requested: reverse(s='eantuhontaehu')

uheatnohutnae
The reverse of "eantuhontaehu" is "uheatnohutnae".