File size: 2,803 Bytes
e5034c3 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 | use proc_macro::TokenStream;
use quote::{ToTokens, quote};
use syn::{DeriveInput, Expr, ExprLit, Lit, parse_macro_input};
/// Custom attribute for specifying tool description file path
extern crate proc_macro;
#[proc_macro_attribute]
pub fn tool_description_file(_attr: TokenStream, _item: TokenStream) -> TokenStream {
// This is just a marker attribute, the actual processing happens in
// ToolDescription
_item
}
#[proc_macro_derive(ToolDescription, attributes(tool_description_file))]
pub fn derive_description(input: TokenStream) -> TokenStream {
// Parse the input struct or enum
let input = parse_macro_input!(input as DeriveInput);
let name = &input.ident;
let generics = &input.generics;
// Check for tool_description_file attribute first
let mut description_file = None;
for attr in &input.attrs {
if attr.path().is_ident("tool_description_file")
&& let syn::Meta::NameValue(name_value) = &attr.meta
&& let Expr::Lit(ExprLit { lit: Lit::Str(lit_str), .. }) = &name_value.value
{
description_file = Some(lit_str.value());
}
}
// If we have a description file, read it at compile time
let doc_string = if let Some(file_path) = description_file {
std::fs::read_to_string(&file_path)
.unwrap_or_else(|e| {
panic!(
"Failed to read tool description file '{}': {}",
file_path, e
)
})
.trim()
.to_string()
} else {
// Collect doc lines from doc comments
let mut doc_lines = Vec::new();
for attr in &input.attrs {
if attr.path().is_ident("doc") {
// Get the doc content as a string
let doc_string = attr.meta.to_token_stream().to_string();
// Remove the quotes and = sign
let clean = doc_string.trim_start_matches("=").trim_matches('"').trim();
if !clean.is_empty() {
doc_lines.push(clean.to_string());
}
}
}
if doc_lines.is_empty() {
panic!("No doc comment found for {name}");
}
doc_lines.join("\n")
};
// Generate the implementation
let expanded = if generics.params.is_empty() {
quote! {
impl ToolDescription for #name {
fn description(&self) -> String {
#doc_string.into()
}
}
}
} else {
quote! {
impl #generics ToolDescription for #name #generics {
fn description(&self) -> String {
#doc_string.into()
}
}
}
};
expanded.into()
}
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