Add from_file class method to the Prompt object

[rlouf]

We keep coming back to the following pattern: first write the prompt in docstrings, and move it to a text file once it gets too large. It would be nice if Outlines made it easy for users to generate a prompt template from a text file. The file can contain plain text, or be written using the Jinja2 templating syntax.

I propose to add a from_file classmethod, which reads the file, extracts the names of the free variables (if any) in the template, and returns a Prompt instance.

[yvan-sraka]

What does the user code look like currently, and what would it look like after this change? This seems like a pretty standard design.

Would you, at some point, like to have a CLI automation tool that helps users extract docstrings of interest to external files in a given subfolder, to help “standardize” what a project using outlines would look like?

[rlouf]

Currently people would write their prompt in a long block between """ marks in the same file. What we have started doing naturally, and seen others do as well, is to move the prompt to a text file to be able to work on it more easily. And then write logic to import the text. Most of the logic we need to process Jinja templating is already implemented in the Prompt object so it would be a fairly simple addition.

Would you, at some point, like to have a CLI automation tool that helps users extract docstrings of interest to external files in a given subfolder, to help “standardize” what a project using outlines would look like?

Maybe in a distant future, after we've had confirmation from users that transitioning is a pain point