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|
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("http");
rules.remove("url_path");
rules.remove("simple_label");
rules.remove("nonreserved_label");
rules.remove("expression");
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*
}}"
)?;
// TODO: this is a cheat; actually implement inline headers instead
writeln!(
&mut file,
"http = {{
http_raw
~ (whsp
~ using
~ whsp1
~ (import_hashed | ^\"(\" ~ whsp ~ import_hashed ~ whsp ~ ^\")\"))?
}}"
)?;
// TODO: hack; we'll need to upstream a change to the grammar
writeln!(
&mut file,
r#"expression = {{
lambda ~ whsp ~ ^"(" ~ whsp ~ nonreserved_label ~ whsp ~ ^":" ~ whsp1 ~ expression ~ whsp ~ ^")" ~ whsp ~ arrow ~ whsp ~ expression
| if_ ~ whsp1 ~ expression ~ whsp ~ then ~ whsp1 ~ expression ~ whsp ~ else_ ~ whsp1 ~ expression
| let_binding+ ~ in_ ~ whsp1 ~ expression
| forall ~ whsp ~ ^"(" ~ whsp ~ nonreserved_label ~ whsp ~ ^":" ~ whsp1 ~ expression ~ whsp ~ ^")" ~ whsp ~ arrow ~ whsp ~ expression
| operator_expression ~ whsp ~ arrow ~ whsp ~ expression
| merge ~ whsp1 ~ import_expression ~ whsp1 ~ import_expression ~ whsp ~ ^":" ~ whsp1 ~ application_expression
| empty_list_literal
| toMap ~ whsp1 ~ import_expression ~ whsp ~ ^":" ~ whsp1 ~ application_expression
| annotated_expression
}}"#
)?;
writeln!(
&mut file,
r#"empty_list_literal = {{
^"[" ~ whsp ~ ^"]" ~ whsp ~ ^":" ~ whsp1 ~ application_expression
}}"#
)?;
// TODO: this is a cheat; properly support RFC3986 URLs instead
writeln!(&mut file, "url_path = _{{ path }}")?;
writeln!(
&mut file,
"nonreserved_label = _{{
!(builtin ~ !simple_label_next_char) ~ label
}}"
)?;
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(())
}
|
