schala/schala-codegen/src/lib.rs

77 lines
2.1 KiB
Rust

#![feature(proc_macro)]
extern crate proc_macro;
#[macro_use]
extern crate quote;
extern crate syn;
use proc_macro::TokenStream;
use syn::{Attribute, DeriveInput};
fn extract_attribute_arg_by_name(name: &str, attrs: &Vec<Attribute>) -> Option<String> {
use syn::{Meta, Lit, MetaNameValue};
attrs.iter().map(|attr| attr.interpret_meta()).find(|meta| {
match meta {
&Some(Meta::NameValue(MetaNameValue { ident, .. })) if ident.as_ref() == name => true,
_ => false
}
}).and_then(|meta| {
match meta {
Some(Meta::NameValue(MetaNameValue { lit: Lit::Str(litstr), .. })) => Some(litstr.value()),
_ => None,
}
})
}
#[proc_macro_derive(ProgrammingLanguageInterface, attributes(LanguageName, SourceFileExtension, PipelineSteps))]
pub fn derive_programming_language_interface(input: TokenStream) -> TokenStream {
let ast: DeriveInput = syn::parse(input).unwrap();
let name = &ast.ident;
let attrs = &ast.attrs;
let language_name: String = extract_attribute_arg_by_name("LanguageName", attrs).expect("LanguageName is required");
let file_ext = extract_attribute_arg_by_name("SourceFileExtension", attrs).expect("SourceFileExtension is required");
let tokens = quote! {
impl ProgrammingLanguageInterface for #name {
fn get_language_name(&self) -> String {
#language_name.to_string()
}
fn get_source_file_suffix(&self) -> String {
#file_ext.to_string()
}
fn execute_pipeline(&mut self, input: &str, options: &EvalOptions) -> FinishedComputation {
let mut chain = pass_chain![self, options;
tokenizing_stage,
parsing_stage,
symbol_table_stage,
typechecking_stage,
eval_stage
];
chain(input)
}
fn get_stages(&self) -> Vec<String> {
vec![
format!("tokenizing_stage"),
format!("parsing_stage"), //TODO handle both types of this
format!("symbol_table_stage"),
format!("typechecking_stage"),
format!("eval_stage")
]
}
}
};
tokens.into()
}
#[cfg(test)]
mod tests {
#[test]
fn it_works() {
assert_eq!(2 + 2, 4);
}
}