Arena Terms Parser

Parser for arena-backed, Prolog-like terms.

This crate provides a lexer, parser, and operator handling for Prolog-style terms. It depends on the arena_terms crate to store terms efficiently in an arena and is built on top of the parlex runtime library.

Features

Lexer
Tokenizes atoms, variables, numbers, strings, dates, and symbols.
Parser
An SLR(1) parser (generated by parlex-gen) that produces arena_terms::Term values.
Operators
Dynamically handles operator fixity, associativity, and precedence rules.
Arena-backed
Terms are stored compactly in arenas for efficient allocation and traversal.

Installation

Add this crate to your Cargo.toml:

[dependencies]
arena-terms-parser = "0.1"

Also add:

[dependencies]
arena_terms = "0.1"
parlex = "0.1"

Usage

Parsing a string into arena terms:

use arena_terms_parser::parser::parse_term;
use arena_terms::Arena;

fn main() {
    let mut arena = Arena::new();

    let mut parser = TermParser::try_new(b"likes(mary, pizza).".fuse(), None).unwrap();

    if let Some(defs) = defs {
        parser.define_opers(arena, b"[op('+'(x,y), infix, 380, left)]".fuse(), None)?;
    }

    let Some(term) = parser.try_next_term(&mut arena) else { unreachable!() }

    println!("{}", term.display(&arena));
}

CLI

Build the binary with:

cargo build --release --bin arena-terms-parser

Then run:

./target/release/parser --terms input.ax

Documentation

For detailed API documentation, visit docs.rs/parlex.

License

Released under the terms of the GNU Lesser General Public License, version 3.0 or (at your option) any later version (LGPL-3.0-or-later).

arena-terms-parser 0.1.7