spire_enum_macros 0.7.0

pub use attr_kw::delegator as kw_delegator;
use syn::{MacroDelimiter, MetaList, parse_quote};

use super::*;

mod attr_kw {
    use super::*;
    custom_keyword!(delegator);
}

#[derive(ToTokens)]
pub enum SaneVarFields {
    Named(SaneVarFieldsNamed),
    Unnamed(SaneVarFieldsUnnamed),
    Unit,
}

impl SaneVarFields {
    pub fn delegator_field_kw(&self) -> Option<&kw_delegator> {
        match self {
            SaneVarFields::Named(named) => named.delegator.as_ref().map(|(kw, _)| kw),
            SaneVarFields::Unnamed(unnamed) => unnamed.delegator.as_ref().map(|(kw, _)| kw),
            SaneVarFields::Unit => None,
        }
    }
}

pub struct SaneVarFieldsNamed {
    pub fields: Brace<Punctuated<VarFieldNamed<SynMeta>, Token![,]>>,
    pub delegator: Option<(kw_delegator, Ident)>,
}

pub struct SaneVarFieldsUnnamed {
    pub fields: Paren<Punctuated<VarFieldUnnamed<SynMeta>, Token![,]>>,
    pub delegator: Option<(kw_delegator, usize)>,
}

pub fn sanitize_variant_fields(input: VarFields<Meta<kw_delegator>>) -> Result<SaneVarFields> {
    match input {
        VarFields::Named(fields) => {
            let (brace_token, fields) = fields.into_parts();

            let mut delegator: Option<(kw_delegator, Ident)> = None;
            let mut new_fields = Punctuated::<VarFieldNamed<SynMeta>, Token![,]>::new();

            for pair in fields.inner.into_pairs() {
                let (input_field, comma) = pair.into_tuple();
                let (new_field, delegator_option) = sanitize_field_named(input_field)?;
                if let _Some(second) = delegator_option {
                    if let Some((first, _)) = delegator {
                        err_expected_only_one!(first, second);
                    } else {
                        delegator = Some((second, new_field.ident.clone()));
                    }
                }

                new_fields.push_value(new_field);
                if let Some(comma) = comma {
                    new_fields.push_punct(comma);
                }
            }

            Ok(SaneVarFields::Named(SaneVarFieldsNamed {
                fields: Brace::from((brace_token, new_fields)),
                delegator,
            }))
        }
        VarFields::Unnamed(fields) => {
            let (paren_token, fields) = fields.into_parts();

            let mut delegator: Option<(kw_delegator, usize)> = None;
            let mut new_fields = Punctuated::<VarFieldUnnamed<SynMeta>, Token![,]>::new();

            for (idx, pair) in fields.inner.into_pairs().enumerate() {
                let (input_field, comma) = pair.into_tuple();
                let (new_field, delegator_option) = sanitize_field_unnamed(input_field)?;
                if let _Some(second) = delegator_option {
                    if let Some((first, _)) = delegator {
                        err_expected_only_one!(first, second);
                    } else {
                        delegator = Some((second, idx));
                    }
                }

                new_fields.push_value(new_field);
                if let Some(comma) = comma {
                    new_fields.push_punct(comma);
                }
            }

            Ok(SaneVarFields::Unnamed(SaneVarFieldsUnnamed {
                fields: Paren::from((paren_token, new_fields)),
                delegator,
            }))
        }
        VarFields::Unit => Ok(SaneVarFields::Unit),
    }
}

fn sanitize_field_named(
    field: VarFieldNamed<Meta<kw_delegator>>,
) -> Result<(VarFieldNamed<SynMeta>, Optional<kw_delegator>)> {
    let VarFieldNamed {
        attrs,
        ident,
        colon_token,
        ty,
    } = field;

    let (mut syn_attrs, cfg_attrs, custom_metas) = split_input_attrs(attrs.into_inner());
    syn_attrs.extend(cfg_attrs.into_inner().into_iter().map(|cfg_attr| {
        let kw = cfg_attr.inner.kw;
        let (bracket, inner) = cfg_attr.inner.into_parts();
        let (paren, tokens) = inner.tokens.into_parts();

        Attribute {
            pound_token: cfg_attr.pound_token,
            inner: Bracket::from((
                bracket,
                SynMeta::List(MetaList {
                    path: parse_quote! { #kw },
                    delimiter: MacroDelimiter::Paren(paren),
                    tokens,
                }),
            )),
        }
    }));

    let mut delegator: Optional<kw_delegator> = _None;

    for attr in custom_metas {
        let kw = attr.inner.into_inner();
        assign_unique_or_panic!(delegator, kw);
    }

    Ok((
        VarFieldNamed {
            attrs: syn_attrs,
            ident,
            colon_token,
            ty,
        },
        delegator,
    ))
}

fn sanitize_field_unnamed(
    field: VarFieldUnnamed<Meta<kw_delegator>>,
) -> Result<(VarFieldUnnamed<SynMeta>, Optional<kw_delegator>)> {
    let VarFieldUnnamed { attrs, ty } = field;

    let (mut syn_attrs, cfg_attrs, custom_metas) = split_input_attrs(attrs.into_inner());
    syn_attrs.extend(cfg_attrs.into_inner().into_iter().map(|cfg_attr| {
        let kw = cfg_attr.inner.kw;
        let (bracket, inner) = cfg_attr.inner.into_parts();
        let (paren, tokens) = inner.tokens.into_parts();

        Attribute {
            pound_token: cfg_attr.pound_token,
            inner: Bracket::from((
                bracket,
                SynMeta::List(MetaList {
                    path: parse_quote! { #kw },
                    delimiter: MacroDelimiter::Paren(paren),
                    tokens,
                }),
            )),
        }
    }));

    let mut delegator: Optional<kw_delegator> = _None;

    for attr in custom_metas {
        let kw = attr.inner.into_inner();
        assign_unique_or_panic!(delegator, kw);
    }

    Ok((
        VarFieldUnnamed {
            attrs: syn_attrs,
            ty,
        },
        delegator,
    ))
}

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

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