harmos-macros 0.1.13

Procedural macros for Harmos artifacts, catalogs and identities.
Documentation 
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/* ***
 *
 * Harmos
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * ***
 */

/* === Modules === */

/* === Re-Exports === */

/* === Imports === */

// Standard Library Imports

// Third Party Imports
use proc_macro2::TokenStream;
use quote::ToTokens;
use syn::spanned::Spanned;
use syn::{Error, Meta, Path};
// Local Imports

/* === Constants === */

pub(crate) const KEY: &str = "harmos_path";

/* === Macros === */

/* === Type Aliases === */

/* === Structs === */

pub(crate) struct HarmosPath(Path, bool);

/* === Enums === */

/* === Traits === */

/* === Implementations === */

impl HarmosPath {
    pub(crate) fn catalog() -> Self {
        let package = "harmos";
        let Ok(found) = proc_macro_crate::crate_name(package) else {
            return Self(syn::parse_quote!(::harmos), true);
        };
        let name = match found {
            proc_macro_crate::FoundCrate::Itself => package.replace('-', "_"),
            proc_macro_crate::FoundCrate::Name(name) => name,
        };
        let name = syn::Ident::new(&name, proc_macro2::Span::call_site());
        Self(syn::parse_quote!(::#name), true)
    }

    pub(crate) fn resolve(explicit: Option<Path>) -> Self {
        explicit.map(|path| Self(path, true)).unwrap_or_else(Self::catalog)
    }

    pub(crate) fn execution_gate(&self) -> TokenStream {
        if self.1 { quote::quote!(#[cfg(feature = "runtime")]) } else { TokenStream::new() }
    }

    pub(crate) fn runtime_enabled(mut self) -> Self {
        self.1 = false;
        self
    }
}

impl ToTokens for HarmosPath {
    fn to_tokens(&self, tokens: &mut TokenStream) {
        self.0.to_tokens(tokens);
    }
}

/* === Public Functions === */

pub(crate) fn declared(meta: &Meta) -> Option<Result<Path, Error>> {
    let Meta::NameValue(named) = meta else {
        return None;
    };
    if !named.path.is_ident(KEY) {
        return None;
    }

    Some(syn::parse2::<Path>(named.value.to_token_stream()).map_err(|error| {
        Error::new(named.value.span(), format!("`{KEY}` names the crate path generated code resolves harmos through: {error}"))
    }))
}

/* === Private Functions === */

/* === Tests === */