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use std::env;
use std::fs::{read_to_string, File};
use std::io::{BufRead, BufReader, Write};
use std::path::Path;
use abnf_to_pest::render_rules_to_pest;
fn convert_abnf_to_pest() -> std::io::Result<()> {
let out_dir = env::var("OUT_DIR").unwrap();
let abnf_path = "src/syntax/text/dhall.abnf";
let visibility_path = "src/syntax/text/dhall.pest.visibility";
let grammar_path = Path::new(&out_dir).join("dhall.pest");
println!("cargo:rerun-if-changed={}", abnf_path);
println!("cargo:rerun-if-changed={}", visibility_path);
let mut data = read_to_string(abnf_path)?;
data.push('\n');
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] == "# " {
if let Some(x) = rules.get_mut(&line[2..]) {
x.silent = true;
}
}
}
let mut file = File::create(grammar_path)?;
writeln!(&mut file, "// AUTO-GENERATED FILE. See build.rs.")?;
// Work around some greediness issue in the grammar.
rules.remove("missing");
writeln!(
&mut file,
r#"missing = {{ "missing" ~ !simple_label_next_char }}"#
)?;
// Prefer my nice error message to illegible parse errors.
rules.remove("unicode_escape");
rules.remove("unbraced_escape");
rules.remove("braced_escape");
rules.remove("braced_codepoint");
rules.remove("unicode_suffix");
writeln!(
&mut file,
r#"unicode_escape = _{{ HEXDIG{{4}} | "{{" ~ HEXDIG+ ~ "}}" }}"#
)?;
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
}}"
)?;
// Setup grammar for precedence climbing
rules.remove("operator_expression");
writeln!(
&mut file,
r##"
import_alt = {{ "?" ~ whsp1 }}
bool_or = {{ "||" }}
natural_plus = {{ "+" ~ whsp1 }}
text_append = {{ "++" }}
list_append = {{ "#" }}
bool_and = {{ "&&" }}
natural_times = {{ "*" }}
bool_eq = {{ "==" }}
bool_ne = {{ "!=" }}
operator = _{{
equivalent |
bool_ne |
bool_eq |
natural_times |
combine_types |
prefer |
combine |
bool_and |
list_append |
text_append |
natural_plus |
bool_or |
import_alt
}}
operator_expression = {{ application_expression ~ (whsp ~ operator ~ whsp ~ application_expression)* }}
"##
)?;
writeln!(
&mut file,
"final_expression = ${{ SOI ~ complete_expression ~ EOI }}"
)?;
writeln!(&mut file)?;
writeln!(&mut file, "{}", render_rules_to_pest(rules).pretty(80))?;
Ok(())
}
// Generate pest parser manually because otherwise we'd need to modify something outside of
// OUT_DIR and that's forbidden by docs.rs.
fn generate_pest_parser() -> std::io::Result<()> {
let out_dir = env::var("OUT_DIR").unwrap();
let grammar_path = Path::new(&out_dir).join("dhall.pest");
let grammar_path = grammar_path.to_str();
let output_path = Path::new(&out_dir).join("dhall_parser.rs");
let pest = quote::quote!(
#[grammar = #grammar_path]
struct DhallParser;
);
let derived = pest_generator::derive_parser(pest, false);
let file_contents = quote::quote!(
struct DhallParser;
#derived
);
let mut file = File::create(output_path)?;
writeln!(file, "{}", file_contents)
}
fn main() -> std::io::Result<()> {
convert_abnf_to_pest()?;
generate_pest_parser()?;
Ok(())
}
|
