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|
use proc_macro2::TokenStream;
use quote::{format_ident, quote, ToTokens};
use syn::{
parse::{Parse, ParseStream},
spanned::Spanned,
};
pub(crate) enum MemberOrString {
Member(syn::Member),
String(syn::LitStr),
}
impl ToTokens for MemberOrString {
fn to_tokens(&self, tokens: &mut TokenStream) {
use MemberOrString::*;
match self {
Member(member) => member.to_tokens(tokens),
String(string) => string.to_tokens(tokens),
}
}
}
impl Parse for MemberOrString {
fn parse(input: ParseStream) -> syn::Result<Self> {
let lookahead = input.lookahead1();
if lookahead.peek(syn::Ident) || lookahead.peek(syn::LitInt) {
Ok(MemberOrString::Member(input.parse()?))
} else if lookahead.peek(syn::LitStr) {
Ok(MemberOrString::String(input.parse()?))
} else {
Err(syn::Error::new(
input.span(),
"Expected a string or a field reference.",
))
}
}
}
use crate::{
diagnostic::{DiagnosticConcreteArgs, DiagnosticDef},
forward::WhichFn,
};
pub(crate) fn gen_all_variants_with(
variants: &[DiagnosticDef],
which_fn: WhichFn,
mut f: impl FnMut(&syn::Ident, &syn::Fields, &DiagnosticConcreteArgs) -> Option<TokenStream>,
) -> Option<TokenStream> {
let pairs = variants
.iter()
.filter_map(|def| {
def.args
.forward_or_override_enum(&def.ident, which_fn, |concrete| {
f(&def.ident, &def.fields, concrete)
})
})
.collect::<Vec<_>>();
if pairs.is_empty() {
return None;
}
let signature = which_fn.signature();
let catchall = which_fn.catchall_arm();
Some(quote! {
#signature {
#[allow(unused_variables, deprecated)]
match self {
#(#pairs)*
#catchall
}
}
})
}
use crate::fmt::Display;
use std::collections::HashSet;
pub(crate) fn gen_unused_pat(fields: &syn::Fields) -> TokenStream {
match fields {
syn::Fields::Named(_) => quote! { { .. } },
syn::Fields::Unnamed(_) => quote! { ( .. ) },
syn::Fields::Unit => quote! {},
}
}
/// Goes in the slot `let Self #pat = self;` or `match self { Self #pat => ...
/// }`.
fn gen_fields_pat(fields: &syn::Fields) -> TokenStream {
let member_idents = fields.iter().enumerate().map(|(i, field)| {
field
.ident
.as_ref()
.cloned()
.unwrap_or_else(|| format_ident!("_{}", i))
});
match fields {
syn::Fields::Named(_) => quote! {
{ #(#member_idents),* }
},
syn::Fields::Unnamed(_) => quote! {
( #(#member_idents),* )
},
syn::Fields::Unit => quote! {},
}
}
/// The returned tokens go in the slot `let Self #pat = self;` or `match self {
/// Self #pat => ... }`. The members can be passed to
/// `Display::expand_shorthand[_cloned]`.
pub(crate) fn display_pat_members(fields: &syn::Fields) -> (TokenStream, HashSet<syn::Member>) {
let pat = gen_fields_pat(fields);
let members: HashSet<syn::Member> = fields
.iter()
.enumerate()
.map(|(i, field)| {
if let Some(ident) = field.ident.as_ref().cloned() {
syn::Member::Named(ident)
} else {
syn::Member::Unnamed(syn::Index {
index: i as u32,
span: field.span(),
})
}
})
.collect();
(pat, members)
}
impl Display {
/// Returns `(fmt, args)` which must be passed to some kind of format macro
/// without tokens in between, i.e. `format!(#fmt #args)`.
pub(crate) fn expand_shorthand_cloned(
&self,
members: &HashSet<syn::Member>,
) -> (syn::LitStr, TokenStream) {
let mut display = self.clone();
display.expand_shorthand(members);
let Display { fmt, args, .. } = display;
(fmt, args)
}
}
|
