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use proc_macro::{TokenStream, TokenTree, Ident, Span};
macro_rules! tk_error_msg {
($name:literal, &$expected:ident, &$found:ident) => {
let mut error = String::from("compile_error!(\"");
error.push_str($name);
error.push_str(" error: expected `");
error.push_str(& $expected);
error.push_str("`, but found `");
error.push_str(& $found);
error.push_str("`.\");");
return error.parse().unwrap()
};
($name:literal, $expected:ident, $found:ident) => {
let mut error = String::from("compile_error!(\"");
error.push_str($name);
error.push_str(" error: expected `");
error.push_str(&$expected.to_string());
error.push_str("`, but found `");
error.push_str(&$found.to_string());
error.push_str("`.\");");
return error.parse().unwrap()
};
}
macro_rules! tk_assert_eq {
($stream:ident [$index:literal] , Ident($val:literal)) => {
if let TokenTree::Ident(id) = &($stream.clone().into_iter()).nth($index).expect("expected identifier, found nothing") {
let found = id.to_string();
let expected = $val.to_string();
if found != expected {
tk_error_msg!("identifier", &expected, &found);
}
} else {panic!("expected identifier, but found `{:?}`", $stream.clone().into_iter().clone().nth($index).unwrap())}
};
($stream:ident [$index:literal] , Punct($val:literal)) => {
if let TokenTree::Punct(punct) = &($stream.clone().into_iter()).nth($index).expect("expected punctuation, found nothing") {
let expected = $val;
let found = punct.as_char();
if found != $val {
tk_error_msg!("punctuation", expected, found);
}
} else {panic!("expected punctuation, but found `{:?}`", $stream.clone().into_iter().clone().nth($index).unwrap())}
};
($stream:ident [$index:literal] , Literal($val:literal)) => {
if let TokenTree::Literal(li) = &($stream.clone().into_iter()).nth($index).expect("expected literal, found nothing") {
let expected = $val.to_string();
let found = li.to_string();
if expected != found {
tk_error_msg!("literal", &expected, &found);
}
} else {panic!("expected literal, found `{:?}`", $stream.clone().into_iter().clone().nth($index).unwrap())}
};
($stream:ident [$index:literal] , Ident(_)) => {
if let TokenTree::Ident(_) = &($stream.clone().into_iter()).nth($index).expect("expected identifier, found nothing") {
} else {panic!("expected identifier, but found `{:?}`", $stream.clone().into_iter().clone().nth($index).unwrap())}
};
($stream:ident [$index:literal] , Punct(_)) => {
if let TokenTree::Punct(_) = &($stream.clone().into_iter()).nth($index).expect("expected punctuation, found nothing") {
} else {panic!("expected punctuation, but found `{:?}`", $stream.clone().into_iter().clone().nth($index).unwrap())}
};
($stream:ident [$index:literal] , Literal(_)) => {
if let TokenTree::Literal(_) = &($stream.clone().into_iter()).nth($index).expect("expected literal, found nothing") {
} else {
return "compile_error!(\"expected literal\");".parse().unwrap();
}
};
($stream:ident [$index:literal] , Group(_)) => {
if let TokenTree::Group(_) = &($stream.clone().into_iter()).nth($index).expect("expected group, found nothing") {
} else {
return "compile_error!(\"expected group\");".parse().unwrap();
}
};
}
macro_rules! tk_parse {
($lexemes:literal) => {$lexemes.parse::<TokenStream>().unwrap()};
($stream:ident [$index:literal]) => {TokenStream::from($stream.clone().into_iter().clone().nth($index).unwrap())};
($token:ident) => {TokenStream::from($token.clone())};
}
macro_rules! expand_ident {
($token:ident) => {if let TokenTree::Ident(id) = $token.clone() {id} else {panic!()}}
}
#[derive(Clone, Copy)]
enum Consume {
Visibility,
Skip,
Prefix,
Param
}
#[proc_macro_attribute]
pub fn dylink (attr: TokenStream, item: TokenStream) -> TokenStream{
tk_assert_eq!(attr[0], Ident("name"));
tk_assert_eq!(attr[1], Punct('='));
tk_assert_eq!(attr[2], Literal(_));
tk_assert_eq!(item[0], Ident("extern"));
tk_assert_eq!(item[1], Literal(_));
tk_assert_eq!(item[2], Group(_));
let mut item_ret = TokenStream::new();
if let TokenTree::Group(group) = item.clone().into_iter().nth(2).expect("p-0") {
let mut use_after_skip = Consume::Skip;
let mut function_name: Ident = Ident::new("uninitialized", Span::call_site());
let mut begin_declaration = true;
let mut command = Consume::Visibility;
let mut param_list = TokenStream::new();
for token in group.stream().clone() {
if begin_declaration {
item_ret.extend(tk_parse!("#[allow(non_upper_case_globals)]"));
begin_declaration = false;
}
match &token {
TokenTree::Ident(identifier) => if "fn" == identifier.clone().to_string() {
command = Consume::Skip;
use_after_skip = Consume::Prefix;
},
TokenTree::Punct(punct) => if ';' == punct.clone().as_char() {
item_ret.extend(tk_parse!("> ="));
let mut init_function_block = "dylink::Lazy::new(|| unsafe {std::mem::transmute(".to_string();
if let TokenTree::Literal(li) = &(attr.clone().into_iter()).nth(2).expect("attribute: range error (diagnostic not implemented)") {
let mut li = li.to_string();
li.make_ascii_lowercase();
if li == "\"vulkan-1\"" {
init_function_block.push_str("dylink::vkloader(\"");
init_function_block.push_str(&function_name.to_string());
if let Option::Some(TokenTree::Punct(punct)) = &(attr.clone().into_iter()).nth(3) {
if punct.to_string() != "," {
let mut error = String::from("compile_error!(\"punctuation error: expected `,`, but found `");
error.push_str(&punct.to_string());
error.push_str("`.\");");
return error.parse().unwrap();
} else {
tk_assert_eq!(attr[4], Ident("context"));
tk_assert_eq!(attr[5], Punct('='));
init_function_block.push_str("\",");
let mut index = 6;
loop {
if let Option::Some(token) = &(attr.clone().into_iter()).nth(index) {
init_function_block.push_str(&token.to_string());
index += 1;
} else {break;}
}
init_function_block.push_str("))});");
}
} else {
init_function_block.push_str("\", dylink::Context::new()))});");
}
} else if li == "\"opengl32\"" {
init_function_block.push_str("dylink::glloader(\"");
init_function_block.push_str(&function_name.to_string());
init_function_block.push_str("\"))});");
}
else {
init_function_block.push_str("dylink::loader(");
init_function_block.push_str(&li.to_string());
init_function_block.pop();
init_function_block.push_str(".dll\",\"");
init_function_block.push_str(&function_name.to_string());
init_function_block.push_str("\"))});");
}
}
item_ret.extend(init_function_block.parse::<TokenStream>().unwrap());
param_list = TokenStream::new();
command = Consume::Skip;
use_after_skip = Consume::Visibility;
begin_declaration = true;
},
_ => {}
}
match command {
Consume::Visibility => item_ret.extend(tk_parse!(token)),
Consume::Prefix => {
function_name = expand_ident!(token);
item_ret.extend(tk_parse!("static"));
item_ret.extend(tk_parse!(token));
item_ret.extend(tk_parse!(": dylink::Lazy<unsafe extern"));
item_ret.extend(tk_parse!(item[1]));
item_ret.extend(tk_parse!("fn"));
command = Consume::Param;
}
Consume::Param => {
item_ret.extend(tk_parse!(token));
param_list.extend(tk_parse!(token));
}
Consume::Skip => command = use_after_skip
}
}
} else {return tk_parse!("compile_error!(\"expected group\");");}
item_ret
}