modular-bitfield-impl 0.13.1

Derive macro for modular-bitfield
Documentation 
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mod analyse;
mod config;
mod expand;
mod field_config;
mod field_info;
mod params;

use self::{config::Config, params::ParamArgs};
use core::convert::TryFrom;
use proc_macro2::{Span, TokenStream as TokenStream2};
use syn::{self, parse::Result};

/// Analyzes the given token stream for `#[bitfield]` properties and expands code if valid.
pub fn analyse_and_expand(args: TokenStream2, input: TokenStream2) -> TokenStream2 {
    match analyse_and_expand_or_error(args, input) {
        Ok(output) => output,
        Err(err) => err.to_compile_error(),
    }
}

/// Analyzes the given token stream for `#[bitfield]` properties and expands code if valid.
///
/// # Errors
///
/// If the given token stream does not yield a valid `#[bitfield]` specifier.
fn analyse_and_expand_or_error(args: TokenStream2, input: TokenStream2) -> Result<TokenStream2> {
    let input = syn::parse2::<syn::ItemStruct>(input)?;
    let params = syn::parse2::<ParamArgs>(args)?;
    let mut config = Config::default();
    config.feed_params(params)?;
    let bitfield = BitfieldStruct::try_from((&mut config, input))?;
    Ok(bitfield.expand(&config))
}

/// Type used to guide analysis and expansion of `#[bitfield]` structs.
struct BitfieldStruct {
    /// The input `struct` item.
    item_struct: syn::ItemStruct,
}

fn raise_skip_error(skip_params: &str, span: Span, previous: Span) -> Result<()> {
    Err(crate::errors::CombineError::into_combine(
        format_err!(
            span,
            "encountered duplicate `#[skip{}]` attribute for field",
            skip_params
        ),
        format_err!(previous, "duplicate `#[skip{}]` here", skip_params),
    ))
}