abnf is a toolkit for working with Augmented Backus–Naur Form (ABNF) grammars in Go, implementing the specifications from RFC 5234 and RFC 7405. It delivers reusable parsing operators, ready-made rule sets, and a CLI/code generation pipeline that help you build fast and reliable parsers.

Inspired by declaresub/abnf and elimity-com/abnf.

• Features
• Installation
  • Library
  • CLI
• Quick Start
• Packages
• CLI Overview
• Contributing
• License

• Composable ABNF operators mirroring the RFC syntax and semantics.
• High-performance node reuse with pooling and optional caching.
• Generated rule sets for RFC core and definition grammars.
• Detailed error tracing with optional lightweight errors when you need speed.
• CLI tool and code generator for turning ABNF grammar files into Go packages.

go get github.com/ghettovoice/abnf@latest

go install github.com/ghettovoice/abnf/cmd/abnf@latest

package main

import (
    "fmt"

    "github.com/ghettovoice/abnf"
)

var op = abnf.Concat(
    `"a" "b" *"cd"`,
    abnf.Literal(`"a"`, []byte("a")),
    abnf.Literal(`"b"`, []byte("b")),
    abnf.Repeat0Inf(`*"cd"`, abnf.Literal(`"cd"`, []byte("cd"))),
)

func main() {
    nodes := abnf.NewNodes()
    defer nodes.Free()

    input := []byte("abcdcd")
    if err := op(input, 0, nodes); err != nil {
        panic(err)
    }

    best := nodes.Best()
    fmt.Printf("matched: %s (len=%d)\n", best.String(), best.Len())
}

The abnf CLI scaffolds configs and generates Go code from .abnf sources. Typical workflow:

1. Generate a starter config: abnf config ./grammar.yml
2. Update the YAML with your grammar files and output options.
3. Run abnf generate ./grammar.yml to emit ready-to-use Go sources.

Issues and pull requests are welcome. To get started:

make test
make lint
make bench

Distributed under the MIT License. See LICENSE for details.

Third-party dependencies are listed in THIRD-PARTY-LICENSES.md.