package json

import "github.com/tdewolff/parse/json"

Package json is a JSON parser following the specifications at http://json.org/.

Index ¶

• Variables
• type GrammarType
• func (gt GrammarType) String() string
• type Parser
• func NewParser(r io.Reader) *Parser
• func (p Parser) Err() error
• func (p *Parser) Next() (GrammarType, []byte)
• func (p *Parser) State() State
• type State
• func (state State) String() string

Examples ¶

• NewParser

Variables ¶

var ErrBadArrayEnding = errors.New("unexpected right bracket character")

ErrBadArrayEnding is returned when an unexpected right bracket is encountered.

var ErrBadComma = errors.New("unexpected comma character outside an array or object")

ErrBadComma is returned when an unexpected comma is encountered.

var ErrBadObjectDeclaration = errors.New("expected colon character after object key")

ErrBadObjectDeclaration is returned when the object key is not followed by a colon character.

var ErrBadObjectEnding = errors.New("unexpected right brace character")

ErrBadObjectEnding is returned when an unexpected right brace is encountered.

var ErrBadObjectKey = errors.New("expected object key to be a quoted string")

ErrBadObjectKey is returned when the object key is not a quoted string.

var ErrNoComma = errors.New("expected comma character or an array or object ending")

ErrNoComma is returned when no comma is present between two values.

Types ¶

type GrammarType ¶

type GrammarType uint32

GrammarType determines the type of grammar

const (
	ErrorGrammar GrammarType = iota // extra grammar when errors occur
	WhitespaceGrammar
	LiteralGrammar
	NumberGrammar
	StringGrammar
	StartObjectGrammar // {
	EndObjectGrammar   // }
	StartArrayGrammar  // [
	EndArrayGrammar    // ]
)

GrammarType values.

func (GrammarType) String ¶

func (gt GrammarType) String() string

String returns the string representation of a GrammarType.

type Parser ¶

type Parser struct {
	// contains filtered or unexported fields
}

Parser is the state for the lexer.

func NewParser ¶

func NewParser(r io.Reader) *Parser

NewParser returns a new Parser for a given io.Reader.

{
	p := NewParser(bytes.NewBufferString(`{"key": 5}`))
	out := ""
	for {
		state := p.State()
		tt, data := p.Next()
		if tt == ErrorGrammar {
			break
		}
		if state == ObjectKeyState && tt != EndObjectGrammar {
			out += "\""
		}
		out += string(data)
		if state == ObjectKeyState && tt != EndObjectGrammar {
			out += "\":"
		}
		// not handling comma insertion
	}
	fmt.Println(out)
	// Output: {"key":5}
}

{"key":5}

func (Parser) Err ¶

func (p Parser) Err() error

Err returns the error encountered during tokenization, this is often io.EOF but also other errors can be returned.

func (*Parser) Next ¶

func (p *Parser) Next() (GrammarType, []byte)

Next returns the next Grammar. It returns ErrorGrammar when an error was encountered. Using Err() one can retrieve the error message.

func (*Parser) State ¶

func (p *Parser) State() State

State returns the state the parser is currently in (ie. which token is expected).

type State ¶

type State uint32

State determines the current state the parser is in.

const (
	ValueState State = iota // extra token when errors occur
	ObjectKeyState
	ObjectValueState
	ArrayState
)

State values.

func (State) String ¶

func (state State) String() string

String returns the string representation of a State.

Source Files ¶

parse.go