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extern crate proc_macro;
use quote::quote;
use std::collections::HashMap;
use syn::{Ident, Token, Type};
struct TranslationParameters {
pub arguments: Vec<(Ident, Type)>,
}
impl Default for TranslationParameters {
fn default() -> Self {
TranslationParameters {
arguments: Vec::new(),
}
}
}
impl syn::parse::Parse for TranslationParameters {
fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> {
let mut arguments = Vec::new();
while !input.is_empty() {
let param_name = input.parse::<syn::Ident>()?;
input.parse::<Token![:]>()?;
let type_name = input.parse::<syn::Type>()?;
arguments.push((param_name, type_name));
if input.peek(Token![,]) {
input.parse::<Token![,]>().unwrap();
}
}
Ok(TranslationParameters { arguments })
}
}
struct TranslationParse {
pub translation_keys: HashMap<Ident, TranslationParameters>,
}
impl syn::parse::Parse for TranslationParse {
fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> {
let mut translation_keys = HashMap::new();
while !input.is_empty() {
let next_translation = input.parse::<syn::Ident>()?;
if input.peek(Token![,]) || input.is_empty() {
translation_keys.insert(next_translation, TranslationParameters::default());
} else {
let content;
syn::parenthesized!(content in input);
translation_keys
.insert(next_translation, content.parse::<TranslationParameters>()?);
}
if input.peek(Token![,]) {
input.parse::<Token![,]>().unwrap();
}
}
Ok(TranslationParse { translation_keys })
}
}
#[proc_macro]
pub fn generate_translation(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
let translation_parse = syn::parse_macro_input!(input as TranslationParse);
let mut str_gen = quote! {};
let mut fn_gen = quote! {};
for (translation_key, translation_arguments) in translation_parse.translation_keys {
let internal_field_name = Ident::new(
&(translation_key.to_string() + "_implementation_name_plz_dont_use_this_name_plz"),
proc_macro2::Span::call_site(),
);
let external_name = translation_key.to_string();
let serde_rename_field = if cfg!(feature = "serde") {
quote! {
#[serde(rename = #external_name)]
}
} else {
quote! {}
};
str_gen = quote! {
#str_gen
#serde_rename_field
#internal_field_name: String,
};
let mut param_decl = quote! { &self, };
let mut param_call = quote! {};
fn_gen = if translation_arguments.arguments.is_empty() {
quote! {
#fn_gen
pub fn #translation_key ( #param_decl ) -> &str {
&self.#internal_field_name
}
}
} else {
for (id, ty) in translation_arguments.arguments {
param_decl = quote! {
#param_decl
#id: #ty,
};
param_call = quote! {
#param_call
params.insert(stringify!(#id).to_owned(), #id.to_string());
};
}
quote! {
#fn_gen
pub fn #translation_key ( #param_decl ) -> Result<String, strfmt::FmtError> {
use std::collections::HashMap;
let mut params : HashMap<String, String> = HashMap::new();
#param_call
strfmt::strfmt(&self.#internal_field_name, ¶ms)
}
}
};
}
let serde_derive = if cfg!(feature = "serde") {
quote! {
#[derive(serde::Serialize, serde::Deserialize)]
}
} else {
quote! {}
};
let final_generated_struct = quote! {
#serde_derive
pub struct TranslationProvider {
#str_gen
}
impl TranslationProvider {
#fn_gen
}
};
let final_output = quote! {
#final_generated_struct
impl TranslationProvider {
fn generated_code() -> String {
stringify!(#final_generated_struct).to_owned()
}
}
};
proc_macro::TokenStream::from(final_output)
}