bibtex-parser

BibTeX parser for Rust.

bibtex-parser parses BibTeX into structured Rust types. It supports strict parsing by default, opt-in tolerant recovery, source locations, raw-text retention, semantic helpers, editing primitives, streaming, multi-file corpus parsing, and configurable serialization.

Performance Snapshot

Measured on tests/fixtures/tugboat.bib: 2,701,551 bytes, 73,993 lines, and 3,644 entries. Hardware was AMD Ryzen 5 5600G, 6 cores / 12 threads. Measured on 2026-05-13 with Rust 1.93.0; throughput is input-size normalized.

The first table compares parser modes that return reusable bibliography data. The second table keeps narrower throughput baselines separate because those rows intentionally do less work than a full document parse.

Reproduction commands are listed in Reproducing Benchmarks.

Install

[dependencies]
bibtex-parser = "0.2"

Enable optional functionality as needed:

[dependencies]
bibtex-parser = { version = "0.2", features = ["parallel", "latex_to_unicode"] }

• parallel: Rayon-backed parsing for multiple files.
• latex_to_unicode: LaTeX accent-to-Unicode conversion helpers.
• python-extension: PyO3 extension module used by the citerra package.

Core Types

• Library is the compact bibliography collection for application code that needs entries, fields, strings, comments, preambles, validation, transforms, and writing.
• ParsedDocument is the source-preserving document for tooling that needs diagnostics, source-order blocks, raw source text, partial entries, failed blocks, and source locations.
• Parser configures strict versus tolerant parsing, source capture, raw-text preservation, expanded values, streaming, and multi-source parsing.

Strict parsing is the default. Tolerant parsing is explicit.

Parse

use bibtex_parser::{Library, Result};

fn main() -> Result<()> {
    let input = r#"
        @string{venue = "VLDB"}
        @article{paper,
            author = "Jane Doe and John Smith",
            title = "Example Paper",
            journal = venue,
            year = 2026
        }
    "#;

    let library = Library::parse(input)?;
    let entry = library.find_by_key("paper").unwrap();

    assert_eq!(entry.get("journal"), Some("VLDB"));
    assert_eq!(entry.year(), Some("2026".to_string()));
    assert_eq!(entry.authors().len(), 2);
    Ok(())
}

Tolerant Parsing

Use tolerant mode when a corpus may contain malformed entries but valid entries before or after those regions should still be returned.

use bibtex_parser::{Block, Library, Result};

fn main() -> Result<()> {
    let library = Library::parser()
        .tolerant()
        .capture_source()
        .parse(r#"
            @article{ok, title = "Good"}
            @article{bad, title = "Missing close"
            @book{recovered, title = "Recovered"}
        "#)?;

    assert_eq!(library.entries().len(), 2);
    assert_eq!(library.failed_blocks().len(), 1);

    for block in library.blocks() {
        if let Block::Failed(failed) = block {
            eprintln!("bad block at {:?}", failed.source);
        }
    }

    Ok(())
}

Diagnostics And Source Locations

Parse into ParsedDocument when callers need source-order blocks, diagnostics, locations, partial entries, or raw text.

use bibtex_parser::{ParseStatus, Parser, Result};

fn main() -> Result<()> {
    let document = Parser::new()
        .tolerant()
        .capture_source()
        .preserve_raw()
        .expand_values()
        .parse_source("refs/main.bib", r#"
            @article{paper, title = "Example Paper"}
            @article{broken, title = "Missing close"
        "#)?;

    assert_eq!(document.status(), ParseStatus::Partial);
    assert_eq!(document.entries()[0].key(), "paper");

    for diagnostic in document.diagnostics() {
        eprintln!("{}: {}", diagnostic.code, diagnostic.message);
    }

    Ok(())
}

Query, Edit, And Write

use bibtex_parser::{Library, Result, Writer, WriterConfig};

fn main() -> Result<()> {
    let mut library = Library::parse(r#"
        @article{paper,
            title = "Example Paper",
            doi = "https://doi.org/10.1000/XYZ.",
            keywords = "rust; parsing, bibtex"
        }
    "#)?;

    let entry = &mut library.entries_mut()[0];
    entry.set_literal("note", "accepted");
    entry.rename_field("keywords", "tags");

    library.normalize_doi_fields();

    let config = WriterConfig {
        indent: "  ".to_string(),
        align_values: true,
        sort_fields: true,
        ..Default::default()
    };

    let mut output = Vec::new();
    Writer::with_config(&mut output, config).write_library(&library)?;

    let entry = &library.entries()[0];
    assert_eq!(entry.doi(), Some("10.1000/xyz".to_string()));
    assert_eq!(entry.get("note"), Some("accepted"));
    assert_eq!(entry.get("tags"), Some("rust; parsing, bibtex"));
    Ok(())
}

For simple serialization:

let bibtex = library.to_bibtex()?;
library.write_file("references.bib")?;

Semantic Helpers

use bibtex_parser::{Library, ResourceKind, Result};

fn main() -> Result<()> {
    let library = Library::parse(r#"
        @article{paper,
            author = "Jane Doe and {Research Group}",
            date = "2026-05-13",
            doi = "https://doi.org/10.1000/XYZ."
        }
    "#)?;

    let entry = &library.entries()[0];
    assert_eq!(entry.authors()[1].literal.as_deref(), Some("Research Group"));
    assert_eq!(entry.date_parts().unwrap().unwrap().month, Some(5));
    assert_eq!(entry.resource_fields()[0].kind, ResourceKind::Doi);
    assert_eq!(entry.doi(), Some("10.1000/xyz".to_string()));
    Ok(())
}

Helpers include name parsing, date extraction, DOI normalization, field normalization, resource classification, duplicate-key detection, and validation.

Streaming And Multi-File Parsing

Streaming lets callers process source-order events without building a full intermediate collection:

use bibtex_parser::{ParseEvent, ParseFlow, Parser, Result};

fn main() -> Result<()> {
    let mut entries = 0;
    let summary = Parser::new().parse_events("@article{paper, title = \"A\"}", |event| {
        if let ParseEvent::Entry(entry) = event {
            assert_eq!(entry.key(), "paper");
            entries += 1;
        }
        Ok(ParseFlow::Continue)
    })?;

    assert_eq!(entries, 1);
    assert_eq!(summary.entries, 1);
    Ok(())
}

Multi-source parsing keeps source identity and can detect duplicate keys across files:

use bibtex_parser::{CorpusSource, Parser, Result, SourceId};

fn main() -> Result<()> {
    let sources = [
        CorpusSource::new("refs/a.bib", "@article{paper, title = \"A\"}"),
        CorpusSource::new("refs/b.bib", "@article{paper, title = \"B\"}"),
    ];

    let corpus = Parser::new().parse_sources(&sources)?;
    let duplicates = corpus.duplicate_keys();

    assert_eq!(corpus.entries().count(), 2);
    assert_eq!(duplicates[0].key, "paper");
    assert!(duplicates[0].cross_source);
    assert_eq!(duplicates[0].occurrences[1].source, SourceId::new(1));
    Ok(())
}

Use Parser::parse_files with the parallel feature for Rayon-backed parsing of multiple files from disk.

Semantics

• Library::parse and Parser::parse are strict by default.
• Parser::tolerant() recovers valid blocks after malformed input and records failures and diagnostics.
• Library expands string definitions and month constants for field access.
• ParsedDocument can retain raw entry, field, value, comment, preamble, string, and failed-block text when preserve_raw() is enabled.
• Source columns are 1-based Unicode scalar columns. Byte spans are also exposed for exact source slicing.
• Writer defaults preserve source order. Sorting, alignment, trailing commas, and normalized output are explicit choices.

Reproducing Benchmarks

The repository includes Criterion benchmarks for parser throughput, tolerant parsing, source-preserving parsing, streaming, writing, corpus parsing, common library operations, and memory-oriented workloads.

Run the parser table:

cargo bench --bench performance --all-features -- --noplot throughput

Run the writing table:

cargo bench --bench performance --all-features -- --noplot writing

Python benchmark notes are in PYTHON.md.

Local Development

This repository uses a Guix manifest for local development:

guix shell -m manifest.scm --

Common gates:

cargo fmt --all -- --check
guix shell -m manifest.scm -- actionlint
cargo clippy --all-targets --all-features -- -D warnings
cargo test --all-features
cargo bench --all-features --no-run

Build and test the Python wheel:

guix shell -m manifest.scm -- maturin build --release --out target/wheels
rm -rf target/python-test
python3 - <<'PY'
from pathlib import Path
from zipfile import ZipFile

wheel = sorted(Path("target/wheels").glob("citerra-*.whl"))[-1]
target = Path("target/python-test")
target.mkdir(parents=True, exist_ok=True)
with ZipFile(wheel) as archive:
    archive.extractall(target)
PY
guix shell -m manifest.scm -- env PYTHONPATH=target/python-test python3 -m pytest tests/python

Python Package

The Python package is citerra. See PYTHON.md.

Release Process

The release workflow builds the Rust crate, Python source distribution, and ABI3 wheels for Linux, macOS, and Windows. Tagging vX.Y.Z runs release validation, creates a GitHub release, publishes to crates.io, and publishes to PyPI when the required repository environments and secrets are configured.

See RELEASE_CHECKLIST.md for the exact release gates and setup requirements.

License

Licensed under either of Apache-2.0 or MIT, at your option.