Derive Macro ToPrompt 

#[derive(ToPrompt)]
{
    // Attributes available to this derive:
    #[prompt]
}

Derives the ToPrompt trait for a struct or enum.

This macro provides two main functionalities depending on the type.

For Structs

It can generate a prompt based on a template string or by creating a key-value representation of the struct’s fields.

Template-based Prompt

Use the #[prompt(template = "...")] attribute to provide a minijinja template. The struct fields will be available as variables in the template. The struct must also derive serde::Serialize.

#[derive(ToPrompt, Serialize)]
#[prompt(template = "User {{ name }} is a {{ role }}.")]
struct UserProfile {
    name: &'static str,
    role: &'static str,
}

Tip: Handling Special Characters in Templates

When using raw string literals (e.g., r#"..."#) for your templates, be aware of a potential parsing issue if your template content includes the # character. To avoid this, use a different number of # symbols for the raw string delimiter.

Problematic Example:

// This might fail to parse correctly
#[prompt(template = r#"{"color": "#FFFFFF"}"#)]
struct Color { /* ... */ }

Solution:

// Use r##"..."## to avoid ambiguity with the inner '#'
#[prompt(template = r##"{"color": "#FFFFFF"}"##)]
struct Color { /* ... */ }

For Enums

For enums, the macro generates a descriptive prompt based on doc comments and attributes, outlining the available variants. See the documentation on the ToPrompt trait for more details.