contained-macros 0.2.1

procedural macros for managing wrappers
Documentation 
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/*
    appellation: impl_binary <module>
    authors: @FL03
*/
use crate::ast::WrapperOpsAst;
use proc_macro2::TokenStream;
use quote::{format_ident, quote};

/// Procedural macro entry point
pub fn impl_wrapper_binary_ops(input: WrapperOpsAst) -> TokenStream {
    let base = impl_core_binary_ops(&input);
    let assign = impl_assign_ops(&input);

    quote! {
        #(#base)*

        #(#assign)*
    }
}

fn impl_core_binary_ops(
    WrapperOpsAst {
        target, field, ops, ..
    }: &WrapperOpsAst,
) -> Vec<TokenStream> {
    let mut impls = Vec::new();
    for (op, call) in ops {
        let _impl = if let Some(f) = field {
            quote! {
                impl<_A, _B, _C> ::core::ops::#op<#target<_B>> for #target<_A>
                where
                    _A: ::core::ops::#op<_B, Output = _C>,
                {
                    type Output = #target<_C>;

                    fn #call(self, rhs: #target<_B>) -> Self::Output {
                        let #f = ::core::ops::#op::#call(self.#f, rhs.#f);
                        #target { #f }
                    }
                }

                impl<'a, _A, _B, _C> ::core::ops::#op<&'a #target<_B>> for #target<_A>
                where
                    _A: ::core::ops::#op<&'a _B, Output = _C>,
                {
                    type Output = #target<_C>;

                    fn #call(self, rhs: &'a #target<_B>) -> Self::Output {
                        let #f = ::core::ops::#op::#call(self.#f, &rhs.#f);
                        #target { #f }
                    }
                }

                impl<'a, _A, _B, _C> ::core::ops::#op<&'a #target<_B>> for &'a #target<_A>
                where
                    &'a _A: ::core::ops::#op<&'a _B, Output = _C>,
                {
                    type Output = #target<_C>;

                    fn #call(self, rhs: &'a #target<_B>) -> Self::Output {
                        let #f = ::core::ops::#op::#call(&self.#f, &rhs.#f);
                        #target { #f }
                    }
                }

                impl<'a, _A, _B, _C> ::core::ops::#op<#target<_B>> for &'a #target<_A>
                where
                    &'a _A: ::core::ops::#op<_B, Output = _C>,
                {
                    type Output = #target<_C>;

                    fn #call(self, rhs: #target<_B>) -> Self::Output {
                        let #f = ::core::ops::#op::#call(&self.#f, rhs.#f);
                        #target { #f }
                    }
                }
            }
        } else {
            quote! {
                impl<_A, _B, _C> ::core::ops::#op<#target<_B>> for #target<_A>
                where
                    _A: ::core::ops::#op<_B, Output = _C>,
                {
                    type Output = #target<_C>;

                    fn #call(self, rhs: #target<_B>) -> Self::Output {
                        #target(::core::ops::#op::#call(self.0, rhs.0))
                    }
                }

                impl<'a, _A, _B, _C> ::core::ops::#op<&'a #target<_B>> for #target<_A>
                where
                    _A: ::core::ops::#op<&'a _B, Output = _C>,
                {
                    type Output = #target<_C>;

                    fn #call(self, rhs: &'a #target<_B>) -> Self::Output {
                        #target(::core::ops::#op::#call(self.0, &rhs.0))
                    }
                }

                impl<'a, _A, _B, _C> ::core::ops::#op<&'a #target<_B>> for &'a #target<_A>
                where
                    &'a _A: ::core::ops::#op<&'a _B, Output = _C>,
                {
                    type Output = #target<_C>;

                    fn #call(self, rhs: &'a #target<_B>) -> Self::Output {
                        #target(::core::ops::#op::#call(&self.0, &rhs.0))
                    }
                }

                impl<'a, _A, _B, _C> ::core::ops::#op<#target<_B>> for &'a #target<_A>
                where
                    &'a _A: ::core::ops::#op<_B, Output = _C>,
                {
                    type Output = #target<_C>;

                    fn #call(self, rhs: #target<_B>) -> Self::Output {
                        #target(::core::ops::#op::#call(&self.0, rhs.0))
                    }
                }
            }
        };
        impls.push(_impl);
    }
    impls
}

fn impl_assign_ops(options: &WrapperOpsAst) -> Vec<TokenStream> {
    let WrapperOpsAst {
        target, field, ops, ..
    } = options;

    let mut impls = Vec::new();
    for (op, call) in ops {
        let op_assign = format_ident!("{}Assign", op);
        let call_assign = format_ident!("{}_assign", call);

        let _impl = if let Some(f) = field {
            quote! {
                impl<_A, _B> ::core::ops::#op_assign<#target<_B>> for #target<_A>
                where
                    _A: ::core::ops::#op_assign<_B>,
                {
                    fn #call_assign(&mut self, rhs: #target<_B>) {
                        ::core::ops::#op_assign::#call_assign(&mut self.#f, rhs.#f)
                    }
                }
            }
        } else {
            quote! {
                impl<_A, _B> ::core::ops::#op_assign<#target<_B>> for #target<_A>
                where
                    _A: ::core::ops::#op_assign<_B>,
                {
                    fn #call_assign(&mut self, rhs: #target<_B>) {
                        ::core::ops::#op_assign::#call_assign(&mut self.0, rhs.0)
                    }
                }
            }
        };
        // register the implementation
        impls.push(_impl);
    }
    impls
}