diff options
Diffstat (limited to 'src/label.rs')
| -rw-r--r-- | src/label.rs | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/src/label.rs b/src/label.rs new file mode 100644 index 0000000..e0bc70a --- /dev/null +++ b/src/label.rs @@ -0,0 +1,207 @@ +use proc_macro2::TokenStream; +use quote::{format_ident, quote}; +use syn::{ + parenthesized, + parse::{Parse, ParseStream}, + spanned::Spanned, + Token, +}; + +use crate::{ + diagnostic::{DiagnosticConcreteArgs, DiagnosticDef}, + fmt::{self, Display}, + forward::WhichFn, + utils::{display_pat_members, gen_all_variants_with}, +}; + +pub struct Labels(Vec<Label>); + +struct Label { + label: Option<Display>, + ty: syn::Type, + span: syn::Member, +} + +struct LabelAttr { + label: Option<Display>, +} + +impl Parse for LabelAttr { + fn parse(input: ParseStream) -> syn::Result<Self> { + // Skip a token. + // This should receive one of: + // - label = "..." + // - label("...") + let _ = input.step(|cursor| { + if let Some((_, next)) = cursor.token_tree() { + Ok(((), next)) + } else { + Err(cursor.error("unexpected empty attribute")) + } + }); + let la = input.lookahead1(); + let label = if la.peek(syn::token::Paren) { + // #[label("{}", x)] + let content; + parenthesized!(content in input); + if content.peek(syn::LitStr) { + let fmt = content.parse()?; + let args = if content.is_empty() { + TokenStream::new() + } else { + fmt::parse_token_expr(&content, false)? + }; + let display = Display { + fmt, + args, + has_bonus_display: false, + }; + Some(display) + } else { + return Err(syn::Error::new(input.span(), "Invalid argument to label() attribute. The first argument must be a literal string.")); + } + } else if la.peek(Token![=]) { + // #[label = "blabla"] + input.parse::<Token![=]>()?; + Some(Display { + fmt: input.parse()?, + args: TokenStream::new(), + has_bonus_display: false, + }) + } else { + None + }; + Ok(LabelAttr { label }) + } +} + +impl Labels { + pub fn from_fields(fields: &syn::Fields) -> syn::Result<Option<Self>> { + match fields { + syn::Fields::Named(named) => Self::from_fields_vec(named.named.iter().collect()), + syn::Fields::Unnamed(unnamed) => { + Self::from_fields_vec(unnamed.unnamed.iter().collect()) + } + syn::Fields::Unit => Ok(None), + } + } + + fn from_fields_vec(fields: Vec<&syn::Field>) -> syn::Result<Option<Self>> { + let mut labels = Vec::new(); + for (i, field) in fields.iter().enumerate() { + for attr in &field.attrs { + if attr.path().is_ident("label") { + let span = if let Some(ident) = field.ident.clone() { + syn::Member::Named(ident) + } else { + syn::Member::Unnamed(syn::Index { + index: i as u32, + span: field.span(), + }) + }; + use quote::ToTokens; + let LabelAttr { label } = + syn::parse2::<LabelAttr>(attr.meta.to_token_stream())?; + labels.push(Label { + label, + span, + ty: field.ty.clone(), + }); + } + } + } + if labels.is_empty() { + Ok(None) + } else { + Ok(Some(Labels(labels))) + } + } + + pub(crate) fn gen_struct(&self, fields: &syn::Fields) -> Option<TokenStream> { + let (display_pat, display_members) = display_pat_members(fields); + let labels = self.0.iter().map(|highlight| { + let Label { span, label, ty } = highlight; + let var = quote! { __miette_internal_var }; + if let Some(display) = label { + let (fmt, args) = display.expand_shorthand_cloned(&display_members); + quote! { + miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(&self.#span) + .map(|#var| miette::LabeledSpan::new_with_span( + std::option::Option::Some(format!(#fmt #args)), + #var.clone(), + )) + } + } else { + quote! { + miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(&self.#span) + .map(|#var| miette::LabeledSpan::new_with_span( + std::option::Option::None, + #var.clone(), + )) + } + } + }); + Some(quote! { + #[allow(unused_variables)] + fn labels(&self) -> std::option::Option<std::boxed::Box<dyn std::iter::Iterator<Item = miette::LabeledSpan> + '_>> { + use miette::macro_helpers::ToOption; + let Self #display_pat = self; + std::option::Option::Some(Box::new(vec![ + #(#labels),* + ].into_iter().filter(Option::is_some).map(Option::unwrap))) + } + }) + } + + pub(crate) fn gen_enum(variants: &[DiagnosticDef]) -> Option<TokenStream> { + gen_all_variants_with( + variants, + WhichFn::Labels, + |ident, fields, DiagnosticConcreteArgs { labels, .. }| { + let (display_pat, display_members) = display_pat_members(fields); + labels.as_ref().and_then(|labels| { + let variant_labels = labels.0.iter().map(|label| { + let Label { span, label, ty } = label; + let field = match &span { + syn::Member::Named(ident) => ident.clone(), + syn::Member::Unnamed(syn::Index { index, .. }) => { + format_ident!("_{}", index) + } + }; + let var = quote! { __miette_internal_var }; + if let Some(display) = label { + let (fmt, args) = display.expand_shorthand_cloned(&display_members); + quote! { + miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(#field) + .map(|#var| miette::LabeledSpan::new_with_span( + std::option::Option::Some(format!(#fmt #args)), + #var.clone(), + )) + } + } else { + quote! { + miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(#field) + .map(|#var| miette::LabeledSpan::new_with_span( + std::option::Option::None, + #var.clone(), + )) + } + } + }); + let variant_name = ident.clone(); + match &fields { + syn::Fields::Unit => None, + _ => Some(quote! { + Self::#variant_name #display_pat => { + use miette::macro_helpers::ToOption; + std::option::Option::Some(std::boxed::Box::new(vec![ + #(#variant_labels),* + ].into_iter().filter(Option::is_some).map(Option::unwrap))) + } + }), + } + }) + }, + ) + } +} |