debate-derive 1.0.0

derive macro for the `debate` CLI arguments parser
Documentation 
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

use heck::ToSnakeCase;
use proc_macro2::TokenStream as TokenStream2;
use quote::quote;
use syn::{Ident, Token, Variant, punctuated::Punctuated};

use crate::{
    common::enumeration::subcommand::{
        Fallback, ParsedSubcommandInfo, SubcommandVariantNormalizedMode,
    },
    generics::AngleBracedLifetime,
    usage::common::struct_usage_items,
};

pub fn derive_usage_enum_subcommand(
    name: &Ident,
    variants: &Punctuated<Variant, Token![,]>,
    lifetime: Option<&AngleBracedLifetime>,
) -> syn::Result<TokenStream2> {
    let parsed_variants = ParsedSubcommandInfo::from_variants(variants)?;
    let command_name = name.to_string().to_snake_case();
    let requirement = match parsed_variants.fallback {
        Fallback::Explicit(_) => quote! {Optional},
        Fallback::Internal(_) => quote! {Mandatory},
    };

    let subcommands = parsed_variants.variants.iter().map(|variant| {
        let subcommand_name = variant.command.as_str();
        let description = variant.docs.quote();

        let items_for_subcommand = match variant.mode.normalized() {
            SubcommandVariantNormalizedMode::Fields(fields) => {
                let items = struct_usage_items(fields, None);
                quote! { ::debate::help::UsageItems::Parameters { parameters: #items } }
            }
            SubcommandVariantNormalizedMode::Newtype(ty) => quote! {
                <#ty as ::debate::help::Usage>::ITEMS
            },
        };

        quote! {
            ::debate::help::Subcommand {
                command: #subcommand_name,
                description: #description,
                usage: #items_for_subcommand,
            }
        }
    });

    Ok(quote! {
        impl #lifetime ::debate::help::Usage for #name #lifetime {
            const NAME: &'static str = #command_name;
            const DESCRIPTION: ::debate::help::Description<'static> =
                ::debate::help::Description::new("TODO SUBCOMMANDS");
            const ITEMS: ::debate::help::UsageItems<'static> =
                ::debate::help::UsageItems::Subcommands {
                    requirement: ::debate::help::Requirement:: #requirement,
                    commands: &[
                        #(#subcommands,)*
                    ],
                };
        }
    })
}