use proc_macro::TokenStream;
use proc_macro2::TokenStream as TokenStream2;
use quote::quote;
use syn::{parse_macro_input, Data, DeriveInput, Field, Index, Path};
fn get_field_by_attr<'a>(data: &'a Data, ident: &str) -> Option<(usize, &'a Field)> {
if let Data::Struct(struct_data) = &data {
let mut fields = struct_data.fields.iter().enumerate().filter(|(_, field)| {
field.attrs.iter().any(|attr| {
attr.path().is_ident("rustyline")
&& attr
.parse_args::<Path>()
.is_ok_and(|arg| arg.is_ident(ident))
})
});
let field = fields.next();
if fields.next().is_some() {
panic!("Only one {:} field is allowed.", ident);
}
field
} else {
None
}
}
fn field_name_or_index_token(index: usize, field: &Field) -> TokenStream2 {
if let Some(ident) = field.ident.as_ref() {
quote!(#ident)
} else {
let index = Index::from(index);
quote!(#index)
}
}
#[proc_macro_derive(Completer, attributes(rustyline))]
pub fn completer_macro_derive(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let name = &input.ident;
let generics = input.generics;
let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
let expanded = if let Some((index, field)) = get_field_by_attr(&input.data, "Completer") {
let field_name_or_index = field_name_or_index_token(index, field);
let field_type = &field.ty;
quote! {
#[automatically_derived]
impl #impl_generics ::rustyline::completion::Completer for #name #ty_generics #where_clause {
type Candidate = <#field_type as ::rustyline::completion::Completer>::Candidate;
fn complete(
&self,
line: &str,
pos: usize,
ctx: &::rustyline::Context<'_>,
) -> ::rustyline::Result<(usize, ::std::vec::Vec<Self::Candidate>)> {
::rustyline::completion::Completer::complete(&self.#field_name_or_index, line, pos, ctx)
}
fn update(&self, line: &mut ::rustyline::line_buffer::LineBuffer, start: usize, elected: &str, cl: &mut ::rustyline::Changeset) {
::rustyline::completion::Completer::update(&self.#field_name_or_index, line, start, elected, cl)
}
}
}
} else {
quote! {
#[automatically_derived]
impl #impl_generics ::rustyline::completion::Completer for #name #ty_generics #where_clause {
type Candidate = ::std::string::String;
}
}
};
TokenStream::from(expanded)
}
#[proc_macro_derive(Helper)]
pub fn helper_macro_derive(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let name = &input.ident;
let generics = input.generics;
let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
let expanded = quote! {
#[automatically_derived]
impl #impl_generics ::rustyline::Helper for #name #ty_generics #where_clause {
}
};
TokenStream::from(expanded)
}
#[proc_macro_derive(Highlighter, attributes(rustyline))]
pub fn highlighter_macro_derive(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let name = &input.ident;
let generics = input.generics;
let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
let expanded = if let Some((index, field)) = get_field_by_attr(&input.data, "Highlighter") {
let field_name_or_index = field_name_or_index_token(index, field);
quote! {
#[automatically_derived]
impl #impl_generics ::rustyline::highlight::Highlighter for #name #ty_generics #where_clause {
fn highlight<'l>(&self, line: &'l str, pos: usize) -> ::std::borrow::Cow<'l, str> {
::rustyline::highlight::Highlighter::highlight(&self.#field_name_or_index, line, pos)
}
fn highlight_prompt<'b, 's: 'b, 'p: 'b>(
&'s self,
prompt: &'p str,
default: bool,
) -> ::std::borrow::Cow<'b, str> {
::rustyline::highlight::Highlighter::highlight_prompt(&self.#field_name_or_index, prompt, default)
}
fn highlight_hint<'h>(&self, hint: &'h str) -> ::std::borrow::Cow<'h, str> {
::rustyline::highlight::Highlighter::highlight_hint(&self.#field_name_or_index, hint)
}
fn highlight_candidate<'c>(
&self,
candidate: &'c str,
completion: ::rustyline::config::CompletionType,
) -> ::std::borrow::Cow<'c, str> {
::rustyline::highlight::Highlighter::highlight_candidate(&self.#field_name_or_index, candidate, completion)
}
fn highlight_char(&self, line: &str, pos: usize, kind: ::rustyline::highlight::CmdKind) -> bool {
::rustyline::highlight::Highlighter::highlight_char(&self.#field_name_or_index, line, pos, kind)
}
}
}
} else {
quote! {
#[automatically_derived]
impl #impl_generics ::rustyline::highlight::Highlighter for #name #ty_generics #where_clause {
}
}
};
TokenStream::from(expanded)
}
#[proc_macro_derive(Hinter, attributes(rustyline))]
pub fn hinter_macro_derive(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let name = &input.ident;
let generics = input.generics;
let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
let expanded = if let Some((index, field)) = get_field_by_attr(&input.data, "Hinter") {
let field_name_or_index = field_name_or_index_token(index, field);
let field_type = &field.ty;
quote! {
#[automatically_derived]
impl #impl_generics ::rustyline::hint::Hinter for #name #ty_generics #where_clause {
type Hint = <#field_type as ::rustyline::hint::Hinter>::Hint;
fn hint(&self, line: &str, pos: usize, ctx: &::rustyline::Context<'_>) -> ::std::option::Option<Self::Hint> {
::rustyline::hint::Hinter::hint(&self.#field_name_or_index, line, pos, ctx)
}
}
}
} else {
quote! {
#[automatically_derived]
impl #impl_generics ::rustyline::hint::Hinter for #name #ty_generics #where_clause {
type Hint = ::std::string::String;
}
}
};
TokenStream::from(expanded)
}
#[proc_macro_derive(Validator, attributes(rustyline))]
pub fn validator_macro_derive(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let name = &input.ident;
let generics = input.generics;
let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
let expanded = if let Some((index, field)) = get_field_by_attr(&input.data, "Validator") {
let field_name_or_index = field_name_or_index_token(index, field);
quote! {
#[automatically_derived]
impl #impl_generics ::rustyline::validate::Validator for #name #ty_generics #where_clause {
fn validate(
&self,
ctx: &mut ::rustyline::validate::ValidationContext,
) -> ::rustyline::Result<::rustyline::validate::ValidationResult> {
::rustyline::validate::Validator::validate(&self.#field_name_or_index, ctx)
}
fn validate_while_typing(&self) -> bool {
::rustyline::validate::Validator::validate_while_typing(&self.#field_name_or_index)
}
}
}
} else {
quote! {
#[automatically_derived]
impl #impl_generics ::rustyline::validate::Validator for #name #ty_generics #where_clause {
}
}
};
TokenStream::from(expanded)
}