lex

Documentation

Index

• Constants
• type CheckRune
• type ItemType
• type Lexer
  • func (l *Lexer) AcceptRun(c CheckRune)
  • func (l *Lexer) AcceptUntil(c CheckRune)
  • func (l *Lexer) Backup()
  • func (l *Lexer) Emit(t ItemType)
  • func (l *Lexer) Errorf(format string, args ...interface{}) StateFn
  • func (l *Lexer) Ignore()
  • func (l *Lexer) Init(input string)
  • func (l *Lexer) Next() (result rune)
  • func (l *Lexer) Peek() rune
• type StateFn

Constants

const EOF = -1

Types

type CheckRune

type CheckRune func(r rune) bool

type ItemType

type ItemType int

ItemType is used to set the type of a token. These constants can be defined in the file containing state functions. Note that their value should be >= 5.

const (
	ItemEOF   ItemType = iota
	ItemError          // error
)

type Lexer

type Lexer struct {
	// NOTE: Using a text scanner wouldn't work because it's designed for parsing
	// Golang. It won't keep track of start position, or allow us to retrieve
	// slice from [start:pos]. Better to just use normal string.
	Input       string    // string being scanned.
	Start       int       // start position of this item.
	Pos         int       // current position of this item.
	Width       int       // width of last rune read from input.
	Items       chan item // channel of scanned items.
	Depth       int       // nesting of {}
	FilterDepth int       // nesting of () inside filter directive.
	Mode        int       // mode based on information so far.
}

func (*Lexer) AcceptRun

func (l *Lexer) AcceptRun(c CheckRune)

func (*Lexer) AcceptUntil

func (l *Lexer) AcceptUntil(c CheckRune)

func (*Lexer) Backup

func (l *Lexer) Backup()

func (*Lexer) Emit

func (l *Lexer) Emit(t ItemType)

Emit emits the item with it's type information.

func (*Lexer) Errorf

func (l *Lexer) Errorf(format string, args ...interface{}) StateFn

Errorf returns the error state function.

func (*Lexer) Ignore

func (l *Lexer) Ignore()

func (*Lexer) Init

func (l *Lexer) Init(input string)

func (*Lexer) Next

func (l *Lexer) Next() (result rune)

Next reads the next rune from the Input, sets the Width and advances Pos.

func (*Lexer) Peek

func (l *Lexer) Peek() rune

type StateFn

type StateFn func(*Lexer) StateFn

stateFn represents the state of the scanner as a function that returns the next state.