flecs_ecs_derive 0.2.0

// System macro expansion

use proc_macro2::TokenStream;
use quote::quote;

use super::expansion::expand_dsl;
use super::parser::Builder;

/// Expansion function for the `system` macro.
///
/// Generates a system builder with the appropriate method calls based on the DSL terms.
///
/// # Arguments
///
/// * `input` - A `Builder` struct containing the system name, world, and DSL terms
///
/// # Returns
///
/// A `TokenStream` containing the generated system builder code
pub fn expand_system(input: Builder) -> TokenStream {
    let mut terms = input.dsl.terms;
    let (iter_type, builder_calls) = expand_dsl(&mut terms);
    let world = input.world;

    match input.name {
        Some(name) => quote! {
            (#world).system_named::<#iter_type>(#name)
            #(
                #builder_calls
            )*
        },
        None => quote! {
            (#world).system::<#iter_type>()
            #(
                #builder_calls
            )*
        },
    }
}