YASnippet for Prompt Templates for Chatgpt-Shell

First, you'll need to install YASnippet.

We can define a new snippet with M-x yas-new-snippet. This will open a new buffer for defining out snippet.

In this example, I'm only going to show how to make templates with text and placeholders. YASnippet is incredibly powerful and supports highly complex templates; read the documentation if you want to explore further. For now, let's just replicate the summarization template.

We'll mostly use tab stop fields and placeholder fields when building our templates. You can read more about them, and about more advanced templating, here.

Here's what a summarization snippet might look like:

# -*- mode: snippet -*-
# name: Concise Summary
# key: gptsum
# contributor: Daniel Liden
# --
<text>$1</text>

Provide a concise summary of the above text within <text> tags.
$0

The $1 and $0 are called tab stop fields. When inserting the snippet with e.g. yas-insert-snippet or by triggering snippet expansion, you can interactively TAB and S-TAB back and forth through the various tab stop fields, filling them in with whatever you want. In this case, you could type/yank a text to summarize in the $1 position.

$0 has a special meaning: it is the exit point, the place the cursor ends up after completing all of the other tab stop fields.

If you want a default value for a given completion field, you can use a placeholder, which is formatted as ${N:default value}. We might modify the above snippet, for example, to say:

# -*- mode: snippet -*-
# name: Concise Summary
# key: gptsum
# contributor: Daniel Liden
# --
<text>${1:The user forgot to include text to summarize. Remind them!}</text>

Provide a concise summary of the above text within <text> tags.
$0

Once you've defined the snippet in the yas-new-snippet buffer, you can save it with C-c C-c. You will then be prompted to choose a "table." This essentially means specifying the emacs mode with which you'd like the snippet to be associated. In this case, for chatgpt-shell, it's chatgpt-shell-mode. Specifying the mode ensures the snippet will be available when you're in chatgpt-shell-mode. You will also be asked whether you want to save the snippet; go ahead and do so if you intend to use it in the future.

To modify a snippet, you can use yas-visit-snippet-file, make changes, and again go through the saving dialogue with C-c C-c.

Note that, in the example snippets above, I've defined a key: this is for snippet expansion (follow the link for more details). With my configuration, in a chatgpt-shell-mode buffer, I can type gptsum followed by TAB to insert this snippet. Alternately, I can select from all available snippets with M-x yas-insert-snippet.

Upon inserting the snippet, my cursor will be at the first tab stop. I can then insert whatever text I want. Upon hitting TAB, the cursor will jump to the next tab stop. In this case, there was only one, so the cursor will jump to the $0 position at the end of the prompt.

With multiple tab stops (e.g. $1, $2, etc.), pressing TAB multiple times would move forward through each position, allowing you to fill in the desired text. S-TAB enables you to move backward through the tab stops.

We're unlike to ever need to summarize text that we manually type into a chatgpt-shell. But we might want to copy some text to the kill ring and ask for a summary, or copy some code and ask for an explanation. We can write a template to accomplish this.

We'll use one more advanced feature of YASnippet to accomplish this: we can embed Emacs-lisp code in a snippet by enclosing it in backticks (``).

Here's a snippet for explaining code by pasting (yanking) the most recent text from the kill ring:

# key: gptce
# name: code-explainer
# --
Explain the following code:
`(yank)`

In particular:
- Step-by-step, what does it do?
- What are the parameters?
- Are there any other noteworthy features of this code?

Answer concisely.
$0

To use this template, you would first copy or kill some code from a buffer, then navigate to your chatgpt-shell buffer, then insert the snippet. The `(yank)` part will automatically be replaced by the copied code.