diff options
Diffstat (limited to 'build.rs')
| -rw-r--r-- | build.rs | 107 |
1 files changed, 106 insertions, 1 deletions
@@ -1,6 +1,111 @@ +use std::fs::File; +use std::io::{Read,Write,BufReader,BufRead}; +use std::collections::HashMap; +use itertools::Itertools; + use lalrpop; -fn main() { +fn abnf_to_pest(data: &Vec<u8>, visibility_map: &HashMap<String, bool>) -> std::io::Result<String> { + use abnf::abnf::*; + fn format_rule(x: Rule, visibility_map: &HashMap<String, bool>) -> String { + let rulename = format_rulename(x.name); + let contents = format_alternation(x.elements); + let visible = visibility_map.get(&rulename).unwrap_or(&true); + let visible = if *visible {""} else {"_"}; + format!("{} = {}{{ {} }}", rulename, visible, contents) + } + fn format_rulename(x: String) -> String { + let x = x.replace("-", "_"); + if x == "if" || x == "else" || x == "as" || x == "let" || x == "in" || x == "fn" { + x + "_" + } else { + x + } + } + fn format_alternation(x: Alternation) -> String { + x.concatenations.into_iter().map(format_concatenation).join("\n | ") + } + fn format_concatenation(x: Concatenation) -> String { + x.repetitions.into_iter().map(format_repetition).join(" ~ ") + } + fn format_repetition(x: Repetition) -> String { + format!("{}{}", format_element(x.element), x.repeat.map(format_repeat).unwrap_or("".into())) + } + fn format_repeat(x: Repeat) -> String { + match (x.min.unwrap_or(0), x.max) { + (0, None) => "*".into(), + (1, None) => "+".into(), + (0, Some(1)) => "?".into(), + (min, None) => format!("{{{},}}", min), + (min, Some(max)) if min == max => format!("{{{}}}", min), + (min, Some(max)) => format!("{{{},{}}}", min, max), + } + } + fn format_element(x: Element) -> String { + use abnf::abnf::Element::*; + match x { + Rulename(s) => format_rulename(s), + Group(g) => format!("({})", format_alternation(g.alternation)), + Option(o) => format!("({})?", format_alternation(o.alternation)), + CharVal(s) => format!("^\"{}\"", s.replace("\"", "\\\"").replace("\\", "\\\\")), + NumVal(r) => format_range(r), + ProseVal(_) => unimplemented!(), + } + } + fn format_range(x: Range) -> String { + use abnf::abnf::Range::*; + match x { + Range(x, y) => format!("'{}'..'{}'", format_char(x), format_char(y)), + OneOf(v) => format!("\"{}\"", v.into_iter().map(format_char).join("")), + } + } + fn format_char(x: u64) -> String { + if x <= (u8::max_value() as u64) { + let x: u8 = x as u8; + if x.is_ascii_graphic() { + let x: char = x as char; + if x != '"' && x != '\'' && x != '\\' { + return x.to_string(); + } + } + } + format!("\\u{{{:02X}}}", x) + } + let make_err = |e| std::io::Error::new(std::io::ErrorKind::Other, format!("{}", e)); + + let rules = rulelist_comp(&data).map_err(make_err)?.1; + Ok(rules.into_iter().map(|x| format_rule(x, visibility_map)).join("\n")) +} + +fn main() -> std::io::Result<()> { lalrpop::process_root().unwrap(); println!("cargo:rerun-if-changed=src/grammar.lalrpop"); + + + let abnf_path = "dhall-lang/standard/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 visibility_map: HashMap<String, bool> = HashMap::new(); + for line in BufReader::new(File::open(visibility_path)?).lines() { + let line = line?; + if line.len() >= 2 && &line[0..2] == "# " { + visibility_map.insert(line[2..].into(), false); + } else { + visibility_map.insert(line, true); + } + } + + let mut file = File::create(pest_path)?; + writeln!(&mut file, "{}", abnf_to_pest(&data, &visibility_map)?)?; + writeln!(&mut file, "final_expression = _{{ SOI ~ complete_expression ~ EOI }}")?; + + Ok(()) } |