use std::env; use std::fs::File; use std::io::{BufRead, BufReader, Read, Write}; use std::path::Path; use abnf_to_pest::render_rules_to_pest; fn main() -> std::io::Result<()> { // TODO: upstream changes to grammar // let abnf_path = "../dhall-lang/standard/dhall.abnf"; let abnf_path = "src/dhall.abnf"; let visibility_path = "src/dhall.pest.visibility"; let pest_path = "src/dhall.pest"; println!("cargo:rerun-if-changed={}", abnf_path); println!("cargo:rerun-if-changed={}", visibility_path); let mut file = File::open(abnf_path)?; let mut data = Vec::new(); file.read_to_end(&mut data)?; data.push('\n' as u8); let mut rules = abnf_to_pest::parse_abnf(&data)?; for line in BufReader::new(File::open(visibility_path)?).lines() { let line = line?; if line.len() >= 2 && &line[0..2] == "# " { rules.get_mut(&line[2..]).map(|x| x.silent = true); } } let mut file = File::create(pest_path)?; writeln!(&mut file, "// AUTO-GENERATED FILE. See build.rs.")?; // TODO: this is a cheat; properly support RFC3986 URLs instead rules.remove("url_path"); writeln!(&mut file, "url_path = _{{ path }}")?; rules.remove("simple_label"); writeln!( &mut file, "simple_label = {{ keyword ~ simple_label_next_char+ | !keyword ~ simple_label_first_char ~ simple_label_next_char* }}" )?; rules.remove("nonreserved_label"); writeln!( &mut file, "nonreserved_label = _{{ !(builtin ~ !simple_label_next_char) ~ label }}" )?; writeln!( &mut file, "final_expression = ${{ SOI ~ complete_expression ~ EOI }}" )?; writeln!(&mut file)?; writeln!(&mut file, "{}", render_rules_to_pest(rules).pretty(80))?; // Generate pest parser manually to avoid spurious recompilations let derived = { let pest_path = "dhall.pest"; let pest = quote::quote! { #[grammar = #pest_path] pub struct DhallParser; }; pest_generator::derive_parser(pest, false) }; let out_dir = env::var("OUT_DIR").unwrap(); let grammar_path = Path::new(&out_dir).join("grammar.rs"); let mut file = File::create(grammar_path)?; writeln!(file, "pub struct DhallParser;\n{}", derived,)?; Ok(()) }