abnf

README

abnf

Package abnf implements ABNF grammar as described in RFC 5234 and RFC 7405.

Inspired by:

• https://github.com/declaresub/abnf
• https://github.com/elimity-com/abnf

Installation

Add abnf package and all subpackages to your project:

go get github.com/ghettovoice/abnf@latest

Usage

Build a rule from basic operators:

package main

import (
    "fmt"

    "github.com/ghettovoice/abnf"
)

var abc = 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() {
    var ns abnf.Nodes

    fmt.Println(abc([]byte("ab"), ns[:0]))
    fmt.Println(abc([]byte("abcd"), ns[:0]))
    fmt.Println(abc([]byte("abcdcd"), ns[:0]))
}

CLI

Checkout abnf CLI README.

License

MIT License - see LICENSE file for a full text.

Documentation

Overview

Package abnf provides basic ABNF operators (RFC 5234, RFC 7405).

Core ABNF rules implementation can be found in github.com/ghettovoice/abnf/pkg/abnf_core, ABNF definition rules are in github.com/ghettovoice/abnf/pkg/abnf_def, code and parser generators are in github.com/ghettovoice/abnf/pkg/abnf_gen.

Index

• Constants
• type Node
  • func (n *Node) Compare(other *Node) int
  • func (n *Node) Contains(key string) bool
  • func (n *Node) GetNode(key string) *Node
  • func (n *Node) GetNodes(key string) Nodes
  • func (n *Node) IsEmpty() bool
  • func (n *Node) Len() int
  • func (n *Node) String() string
• type Nodes
  • func (ns Nodes) Best() *Node
  • func (ns Nodes) Compare(other Nodes) int
  • func (ns Nodes) Contains(key string) bool
  • func (ns Nodes) Get(key string) *Node
  • func (ns Nodes) GetAll(key string) Nodes
• type Operator
  • func Alt(key string, oprts ...Operator) Operator
  • func AltFirst(key string, oprts ...Operator) Operator
  • func Concat(key string, oprts ...Operator) Operator
  • func ConcatAll(key string, oprts ...Operator) Operator
  • func Literal(key string, val []byte) Operator
  • func LiteralCS(key string, val []byte) Operator
  • func Optional(key string, op Operator) Operator
  • func Range(key string, low, high []byte) Operator
  • func Repeat(key string, min, max uint, op Operator) Operator
  • func Repeat0Inf(key string, op Operator) Operator
  • func Repeat1Inf(key string, op Operator) Operator
  • func RepeatN(key string, n uint, op Operator) Operator

Constants

const (
	VERSION = "0.2.0" // package version
)

Types

type Node

type Node struct {
	Key      string
	Value    []byte
	Children Nodes
}

Node represents a single node in a tree generated by Operator.

func (*Node) Compare

func (n *Node) Compare(other *Node) int

Compare compares node values via bytes.Compare. The result will be 0 if n.Value == other.Value, -1 if n.Value < other.Value, and +1 if n.Value > other.Value.

func (*Node) Contains

func (n *Node) Contains(key string) bool

Contains returns whether the subtree contains the given key.

func (*Node) GetNode

func (n *Node) GetNode(key string) *Node

GetNode recursively searches a node with the given key starting from itself. Returns found node and true on success, empty node and false on failure.

func (*Node) GetNodes

func (n *Node) GetNodes(key string) Nodes

GetNodes recursively searches all nodes with the given key starting from itself.

func (*Node) IsEmpty

func (n *Node) IsEmpty() bool

IsEmpty returns true if the node's value length = 0.

func (*Node) Len

func (n *Node) Len() int

Len returns length of the node's value.

func (*Node) String

func (n *Node) String() string

String returns the node's value as string.

type Nodes

type Nodes []*Node

Nodes represents a list of nodes.

func (Nodes) Best

func (ns Nodes) Best() *Node

Best returns a node with the longest value.

func (Nodes) Compare

func (ns Nodes) Compare(other Nodes) int

Compare compares two best nodes. The result will be 0 if a == b, -1 if a < b, and +1 if a > b where a - self best node, b - other best node.

func (Nodes) Contains

func (ns Nodes) Contains(key string) bool

Contains returns whether the subtree contains the given key.

func (Nodes) Get

func (ns Nodes) Get(key string) *Node

Get recursively searches a node with the given key.

func (Nodes) GetAll

func (ns Nodes) GetAll(key string) Nodes

GetAll recursively searches all nodes with the given key.

type Operator

type Operator func(s []byte, ns Nodes) Nodes

Operator represents an ABNF operator.

func Alt

func Alt(key string, oprts ...Operator) Operator

Alt defines a sequence of alternative elements that are separated by a forward slash ("/"). Created operator will return all matched alternatives.

func AltFirst

func AltFirst(key string, oprts ...Operator) Operator

AltFirst defines a sequence of alternative elements that are separated by a forward slash ("/"). Created operator will return first matched alternative.

func Concat

func Concat(key string, oprts ...Operator) Operator

Concat defines a simple, ordered string of values. Created operator will return the longest alternative.

func ConcatAll

func ConcatAll(key string, oprts ...Operator) Operator

ConcatAll defines a simple, ordered string of values. Created operator will return all alternatives.

func Literal

func Literal(key string, val []byte) Operator

Literal defines a case-insensitive characters sequence.

func LiteralCS

func LiteralCS(key string, val []byte) Operator

LiteralCS defines a case-sensitive characters sequence.

func Optional

func Optional(key string, op Operator) Operator

Optional defines an optional element sequence. It is equivalent to repeat 0-1.

func Range

func Range(key string, low, high []byte) Operator

Range defines a range of alternative numeric values.

func Repeat

func Repeat(key string, min, max uint, op Operator) Operator

Repeat defines a variable repetition.

func Repeat0Inf

func Repeat0Inf(key string, op Operator) Operator

Repeat0Inf defines a specific repetition from 0 to infinity.

func Repeat1Inf

func Repeat1Inf(key string, op Operator) Operator

Repeat1Inf defines a specific repetition from 1 to infinity.

func RepeatN

func RepeatN(key string, n uint, op Operator) Operator

RepeatN defines a specific repetition.