diff options
Diffstat (limited to 'dhall_generated_parser/build.rs')
-rw-r--r-- | dhall_generated_parser/build.rs | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/dhall_generated_parser/build.rs b/dhall_generated_parser/build.rs new file mode 100644 index 0000000..615a55c --- /dev/null +++ b/dhall_generated_parser/build.rs @@ -0,0 +1,64 @@ +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); + } + } + rules.remove("simple_label"); + + let mut file = File::create(pest_path)?; + writeln!(&mut file, "// AUTO-GENERATED FILE. See build.rs.")?; + writeln!(&mut file, "{}", render_rules_to_pest(rules).pretty(80))?; + + writeln!(&mut file)?; + writeln!( + &mut file, + "simple_label = {{ + keyword ~ simple_label_next_char+ + | !keyword ~ simple_label_first_char ~ simple_label_next_char* + }}" + )?; + writeln!( + &mut file, + "final_expression = ${{ SOI ~ complete_expression ~ EOI }}" + )?; + + // 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(()) +} |