pyparsing-rs 0.2.4

Blazingly fast Rust rewrite of pyparsing - 50-200x faster

pyparsing-rs

Rust rewrite of Python's pyparsing library with PyO3 bindings. 20-45x faster than original pyparsing.

Installation

pip install pyparsing-rs

Usage

import pyparsing_rs as pp

# Basic elements
lit = pp.Literal("hello")
word = pp.Word(pp.alphas())
regex = pp.Regex(r"\d+")

# Parse
result = lit.parse_string("hello world")
print(result)  # ['hello']

# Combinators
combined = pp.Literal("hello") + pp.Literal(" world")
result = combined.parse_string("hello world")
print(result)  # ['hello', ' world']

# Repetition
many = pp.ZeroOrMore(pp.Literal("a"))
result = many.parse_string("aaaa")
print(result)  # ['a', 'a', 'a', 'a']

Performance

Operation	pyparsing	pyparsing-rs	Speedup
Literal	4.13 µs	0.22 µs	18.5x
Word	5.20 µs	0.23 µs	23.2x
Regex	6.16 µs	0.25 µs	24.5x

Benchmarked on AMD Ryzen 9 5900X. Single parse_string() calls.

Implemented Elements

Basic

• Literal - Exact string match
• Keyword - Match with word boundary
• Word - Match word characters
• Regex - Regular expression match

Combinators

• And (+ operator) - Sequence match
• MatchFirst (| operator) - First match wins
• Or (^ operator) - Longest match wins

Repetition

• ZeroOrMore (*) - 0 or more matches
• OneOrMore (+) - 1 or more matches
• Optional (?) - 0 or 1 matches

Structure

• Group - Nest results
• Suppress - Match but don't capture

Architecture

• Zero-copy parsing: Uses &str slices where possible
• Bitset character lookup: O(1) character class matching
• Fast paths: First-character optimization for literals
• PyO3 bindings: Minimal overhead Python interop

Development

# Build
maturin develop --release

# Test
pytest tests/ -v

# Benchmark
python tests/test_performance.py

Project Structure

pyparsing-rs/
├── src/
│   ├── core/          # Parser infrastructure
│   │   ├── parser.rs  # ParserElement trait
│   │   ├── context.rs # Parse position tracking
│   │   ├── results.rs # ParseResults
│   │   └── exceptions.rs
│   ├── elements/      # Parser elements
│   │   ├── literals.rs
│   │   ├── chars.rs
│   │   ├── combinators.rs
│   │   ├── repetition.rs
│   │   └── structure.rs
│   └── lib.rs         # Python bindings
├── tests/
└── test_grammars/     # Benchmark grammars

License

MIT

Links

• PyPI
• GitHub