optionable_codegen 0.14.2

proc_macro2 functions for the derive macro and codegen implementations in the `optionable_derive` crate to derive nested structs/enums with all subfields being optional (e.g. for patches or Kubernetes server side apply).
Documentation 
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use proc_macro2::TokenStream;
use quote::{quote, ToTokens};

use crate::parsed_input::{FieldHandling, FieldParsed};

/// Returns the `OptionableMapKeysEq` impl if at least one of the struct fields has an `#[optionable_map_key]` attribute, else returns `None`.
pub(crate) fn optionable_map_keys_eq_impl(fields: &[FieldParsed]) -> Option<TokenStream> {
    let key_field_selectors = fields
        .iter()
        .filter(|f| matches!(f.handling, FieldHandling::MapKey))
        .map(|f| f.field.ident.to_token_stream())
        .collect::<Vec<_>>();
    if key_field_selectors.is_empty() {
        return None;
    }
    let comparisons = key_field_selectors
        .into_iter()
        .map(|sel| quote! {self.#sel == other.#sel});
    Some(quote!(#(#comparisons)&&*))
}