reflow

Documentation

Overview

Package reflow supports rewriting the whitespace in a stream of runes.

Index

• Constants
• type Action
• type Rule
  • func AppendDefaultRules(rules []Rule) []Rule
• type Writer
  • func New(to io.Writer) *Writer
  • func (w *Writer) Column() error
  • func (w *Writer) Decrease() error
  • func (w *Writer) DisableUntil(r rune) error
  • func (w *Writer) EOL() error
  • func (w *Writer) Flush() error
  • func (w *Writer) Increase() error
  • func (w *Writer) PushRune(r rune) error
  • func (w *Writer) Reset()
  • func (w *Writer) StrippedEOL() error
  • func (w *Writer) Whitespace(r rune) error
  • func (w *Writer) Write(data []byte) (n int, err error)
  • func (w *Writer) WriteRune(r rune) error

Constants

const (
	EOL      = '¶' // outputs a line break
	Space    = '•' // outputs a space even where it would normally be stripped
	Column   = '║' // a column marker used to line up text
	Toggle   = '§' // switches the formatter on or off
	Disable  = '⋖' // switches the formatter off
	Enable   = '⋗' // switches the formatter back on again
	Indent   = '»' // increases the current indent level by 1
	Unindent = '«' // decreases the current indent level by 1
	Flush    = 'ø' // flushes text, resets column detection
)

Types

type Action

type Action func(w *Writer, r rune) error

Action is the function type invoked for runes being processed by the writer. It is handed the writer and the rune that triggered it.

type Rule

type Rule struct {
	// Rune is the rune to activate the binding for.
	Rune rune
	// Aciton is the funciton to invoke for the matching rune.
	Action
}

Rule is an entry in the rule set that maps a rune to an action.

func AppendDefaultRules

func AppendDefaultRules(rules []Rule) []Rule

AppendDefaultRules adds the default set of rune bindings to a rule set.

The default rules are:

Whitespace at the start and end of input lines, along with the newline characters themselves will be stripped. ¶ Will be replaced by a newline. • Will be converted to a space. It will attempt to line up columns indicated by ║ in adjacent lines using a tabwriter. The indent level can be increased by » and decreased by «. § can be used to disable the reflow behaviours, and reenable them again. ø will flush the writers, reseting all column alignment behaviour.

type Writer

type Writer struct {
	Rules    []Rule // The set of rune actions to apply.
	Depth    int    // The current indentation depth.
	Indent   string // The string to repeat as the indentation.
	Disabled rune   // The current disabled state of the writer.
	Out      io.Writer
	Tabs     *tabwriter.Writer
	To       io.Writer
	// contains filtered or unexported fields
}

Writer is an io.Writer that uses unicode markup to reflow the text passing through it.

func New

func New(to io.Writer) *Writer

New constructs a new reflow Writer with the default indent of 2 spaces. A copy of the default rules are pre-installed in the bindings, and can be modifed at any time. See AppendDefaultRules for the set of rules installed.

func (*Writer) Column

func (w *Writer) Column() error

Column inidcates that a column marker should be inserted for alignement.

func (*Writer) Decrease

func (w *Writer) Decrease() error

Decrease the indent level of the reflow.

func (*Writer) DisableUntil

func (w *Writer) DisableUntil(r rune) error

DisableUntil makes the reflow push all runes through verbatim until the next occurcence of r.

func (*Writer) EOL

func (w *Writer) EOL() error

EOL makes the reflow add an end of line to the output.

func (*Writer) Flush

func (w *Writer) Flush() error

Flush causes any cached bytes to be flushed to the underlying stream. This has the side effect of forcing a reset of column detection.

func (*Writer) Increase

func (w *Writer) Increase() error

Increase the indent level of the reflow.

func (*Writer) PushRune

func (w *Writer) PushRune(r rune) error

PushRune pushes a rune through the reflow logic.

func (*Writer) Reset

func (w *Writer) Reset()

Reset reverts the stream back to the initial state, dropping column, indentation or any other state.

func (*Writer) StrippedEOL

func (w *Writer) StrippedEOL() error

StrippedEOL indicates that an end of line character was suppressed.

func (*Writer) Whitespace

func (w *Writer) Whitespace(r rune) error

Whitespace indicates that the rune should be considered whitespace.

func (*Writer) Write

func (w *Writer) Write(data []byte) (n int, err error)

Write implements io.Writer with the reflow logic.

func (*Writer) WriteRune

func (w *Writer) WriteRune(r rune) error

WriteRune writes the UTF-8 encoding of Unicode code point r, returning an error if it cannot.