rhai/codegen/src/rhai_module.rs
2020-08-06 14:10:27 +08:00

110 lines
4.1 KiB
Rust

use quote::quote;
use crate::function::ExportedFn;
pub(crate) type ExportedConst = (String, syn::Expr);
pub(crate) fn generate_body(
fns: &Vec<ExportedFn>,
consts: &Vec<ExportedConst>,
) -> proc_macro2::TokenStream {
let mut set_fn_stmts: Vec<syn::Stmt> = Vec::new();
let mut set_const_stmts: Vec<syn::Stmt> = Vec::new();
let str_type_path = syn::parse2::<syn::Path>(quote! { str }).unwrap();
for (const_name, const_expr) in consts {
let const_literal = syn::LitStr::new(&const_name, proc_macro2::Span::call_site());
set_const_stmts.push(
syn::parse2::<syn::Stmt>(quote! {
m.set_var(#const_literal, #const_expr);
})
.unwrap(),
);
}
// NB: these are token streams, because reparsing messes up "> >" vs ">>"
let mut gen_fn_tokens: Vec<proc_macro2::TokenStream> = Vec::new();
for function in fns {
let fn_token_name = syn::Ident::new(
&format!("{}_Token", function.name().to_string()),
function.name().span(),
);
let fn_literal =
syn::LitStr::new(&function.name().to_string(), proc_macro2::Span::call_site());
let fn_input_types: Vec<syn::Expr> = function
.arg_list()
.map(|fnarg| match fnarg {
syn::FnArg::Receiver(_) => panic!("internal error: receiver fn outside impl!?"),
syn::FnArg::Typed(syn::PatType { ref ty, .. }) => {
let arg_type = match ty.as_ref() {
&syn::Type::Reference(syn::TypeReference {
mutability: None,
ref elem,
..
}) => match elem.as_ref() {
&syn::Type::Path(ref p) if p.path == str_type_path => {
syn::parse2::<syn::Type>(quote! {
ImmutableString })
.unwrap()
}
_ => panic!("internal error: non-string shared reference!?"),
},
&syn::Type::Reference(syn::TypeReference {
mutability: Some(_),
ref elem,
..
}) => match elem.as_ref() {
&syn::Type::Path(ref p) => syn::parse2::<syn::Type>(quote! {
#p })
.unwrap(),
_ => panic!("internal error: non-string shared reference!?"),
},
t => t.clone(),
};
syn::parse2::<syn::Expr>(quote! {
core::any::TypeId::of::<#arg_type>()})
.unwrap()
}
})
.collect();
set_fn_stmts.push(
syn::parse2::<syn::Stmt>(quote! {
m.set_fn(#fn_literal, FnAccess::Public, &[#(#fn_input_types),*],
CallableFunction::from_plugin(#fn_token_name()));
})
.unwrap(),
);
gen_fn_tokens.push(quote! {
#[allow(non_camel_case_types)]
struct #fn_token_name();
});
gen_fn_tokens.push(function.generate_impl(&fn_token_name.to_string()));
gen_fn_tokens.push(function.generate_callable(&fn_token_name.to_string()));
gen_fn_tokens.push(function.generate_input_types(&fn_token_name.to_string()));
}
let mut generate_fncall = syn::parse2::<syn::ItemMod>(quote! {
pub mod generate_info {
#[allow(unused_imports)]
use super::*;
#[allow(unused_mut)]
pub fn rhai_module_generate() -> Module {
let mut m = Module::new();
#(#set_fn_stmts)*
#(#set_const_stmts)*
m
}
}
})
.unwrap();
let (_, generate_call_content) = generate_fncall.content.take().unwrap();
quote! {
#(#generate_call_content)*
#(#gen_fn_tokens)*
}
}