Get all the field value for a struct as a list

[charleslukes]

This method is same as Object.keys in JS.

Name of the method will be structure.keys()

[oscles]

Hi @charleslukes, I have this approximation

use proc_macro::TokenStream;
use quote::quote;
use syn::{parse_macro_input, Data, DeriveInput, Fields};

#[proc_macro]
pub fn get_struct_fields(input: TokenStream) -> TokenStream {
    // Parse the input tokens into a syntax tree representing a Rust item
    let input = parse_macro_input!(input as DeriveInput);

    // Get the name of the struct
    let _struct_name = &input.ident;

    // Extract the fields of the struct
    let fields = match input.data {
        Data::Struct(ref data_struct) => &data_struct.fields,
        _ => panic!("get_struct_fields macro can only be used with structs"),
    };

    // Extract the field names
    let field_names = match fields {
        Fields::Named(fields) => fields
            .named
            .iter()
            .map(|field| {
                field
                    .ident
                    .as_ref()
                    .expect("Expected named field in struct")
                    .to_string()
            })
            .collect::<Vec<String>>(),
        _ => panic!("get_struct_fields macro can only be used with structs that have named fields"),
    };

    // Generate code to collect field names
    let field_collection = quote! {
        vec![
            #(#field_names),*
        ]
    };

    // Convert the generated code back into tokens
    field_collection.into()
}

But it is only working like this:

use my_macro::get_struct_fields;

fn main() {
    // Use the procedural macro to get all struct fields
    let fields = get_struct_fields!(
        struct MyStruct {
            field1: i32,
            field2: String,
            field3: f64,
        }
    );

    println!("Struct fields: {:?}", fields);
}

And I want that working like this too:

use letsgetrusty::get_struct_fields;

#[derive(Debug)]
struct MyStruct {
    field1: i32,
    field2: String,
    field3: f64,
}

fn main() {
    // Use the procedural macro to get all struct fields
    let fields = get_struct_fields!(MyStruct);
    println!("Struct fields: {:?}", fields);

    let instance = MyStruct {...};
    let fields = get_struct_fields!(instance);
    println!("Struct fields: {:?}", fields);
}