memtable-macros 0.2.0

Macro library that provides ability to derive typed tables and generate tables compile-time.
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use syn::{parse_quote, Ident, ItemFn, Path, Type};

pub struct Args<'a> {
    pub root: &'a Path,
    pub idx: &'a syn::Index,
    pub method_name: &'a Ident,
    pub variant_ty: &'a Type,
    pub table_data_name: &'a Ident,
    pub as_variant: &'a Ident,
}

pub fn make(args: Args) -> ItemFn {
    let Args {
        root,
        idx,
        method_name,
        variant_ty,
        table_data_name,
        as_variant,
    } = args;

    parse_quote! {
        pub fn #method_name(&self) -> impl ::core::iter::Iterator<Item = &#variant_ty> {
            let iter = #root::Table::column(&self.0, #idx);
            ::core::iter::Iterator::filter_map(iter, #table_data_name::#as_variant)
        }
    }
}