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#![recursion_limit="256"]
extern crate proc_macro;
#[macro_use]
extern crate quote;
extern crate relm_gen_widget;
extern crate syn;
use proc_macro::TokenStream;
use quote::Tokens;
use relm_gen_widget::gen_widget;
use syn::{Body, Ident, Item, MacroInput, VariantData, parse_item, parse_macro_input};
use syn::ItemKind::Struct;
use syn::TokenTree::Delimited;
use syn::Ty::Mac;
#[proc_macro_derive(SimpleMsg)]
pub fn simple_msg(input: TokenStream) -> TokenStream {
let string = input.to_string();
let ast = parse_macro_input(&string).unwrap();
let gen = impl_simple_msg(&ast);
gen.parse().unwrap()
}
fn impl_simple_msg(ast: &MacroInput) -> Tokens {
let name = &ast.ident;
let clone = derive_clone(ast);
let display = derive_display_variant(ast);
quote! {
#clone
#display
impl FnOnce<((),)> for #name {
type Output = #name;
extern "rust-call" fn call_once(self, args: ((),)) -> Self::Output {
self.call(args)
}
}
impl FnMut<((),)> for #name {
extern "rust-call" fn call_mut(&mut self, args: ((),)) -> Self::Output {
self.call(args)
}
}
impl Fn<((),)> for #name {
extern "rust-call" fn call(&self, _: ((),)) -> Self::Output {
self.clone()
}
}
}
}
#[proc_macro_derive(Msg)]
pub fn msg(input: TokenStream) -> TokenStream {
let string = input.to_string();
let ast = parse_macro_input(&string).unwrap();
let gen = impl_msg(&ast);
gen.parse().unwrap()
}
fn impl_msg(ast: &MacroInput) -> Tokens {
let clone = derive_clone(ast);
let display = derive_display_variant(ast);
quote! {
#clone
#display
}
}
fn derive_clone(ast: &MacroInput) -> Tokens {
let name = &ast.ident;
if let Body::Enum(ref variants) = ast.body {
let variant_idents_values: Vec<_> = variants.iter().map(|variant| {
let has_value =
if let VariantData::Tuple(_) = variant.data {
true
}
else {
false
};
(&variant.ident, has_value)
}).collect();
let variant_patterns = variant_idents_values.iter().map(|&(ref ident, has_value)| {
if has_value {
quote! {
#name::#ident(ref value)
}
}
else {
quote! {
#name::#ident
}
}
});
let variant_values = variant_idents_values.iter().map(|&(ref ident, has_value)| {
if has_value {
quote! {
#name::#ident(value.clone())
}
}
else {
quote! {
#name::#ident
}
}
});
quote! {
impl Clone for #name {
fn clone(&self) -> Self {
match *self {
#(#variant_patterns => #variant_values,)*
}
}
}
}
}
else {
panic!("Expected enum");
}
}
fn derive_display_variant(ast: &MacroInput) -> Tokens {
let name = &ast.ident;
if let Body::Enum(ref variants) = ast.body {
let variant_idents_values: Vec<_> = variants.iter().map(|variant| {
let has_value =
if let VariantData::Tuple(_) = variant.data {
true
}
else {
false
};
(&variant.ident, has_value)
}).collect();
let variant_patterns = variant_idents_values.iter().map(|&(ref ident, has_value)| {
if has_value {
quote! {
#name::#ident(_)
}
}
else {
quote! {
#name::#ident
}
}
});
let variant_names = variant_idents_values.iter().map(|&(ref ident, _)| {
ident.to_string()
});
quote! {
impl ::relm::DisplayVariant for #name {
fn display_variant(&self) -> &'static str {
match *self {
#(#variant_patterns => #variant_names,)*
}
}
}
}
}
else {
panic!("Expected enum");
}
}
#[proc_macro_derive(Widget)]
pub fn widget(input: TokenStream) -> TokenStream {
let source = input.to_string();
let ast = parse_item(&source).unwrap();
let expanded = impl_widget(&ast);
expanded.parse().unwrap()
}
fn impl_widget(ast: &Item) -> Tokens {
if let Struct(VariantData::Struct(ref fields), _) = ast.node {
for field in fields {
if field.ident == Some(Ident::new("widget")) {
if let Mac(ref mac) = field.ty {
if let Delimited(syn::Delimited { ref tts, .. }) = mac.tts[0] {
let mut tokens = Tokens::new();
tokens.append_all(tts);
return gen_widget(tokens);
}
}
}
}
}
panic!("Expecting `widget` field.");
}