diff

Documentation

Overview

Package diff computes differences between text files or strings.

Index

• func Apply(src string, edits []Edit) (string, error)
• func SortEdits(edits []Edit)
• func ToUnified(oldLabel, newLabel, content string, edits []Edit) (string, error)
• func Unified(oldLabel, newLabel, old, new string) string
• type Edit
  • func Bytes(before, after []byte) []Edit
  • func Strings(before, after string) []Edit
• type OpKind
  • func (k OpKind) String() string

Functions

func Apply

func Apply(src string, edits []Edit) (string, error)

Apply applies a sequence of edits to the src buffer and returns the result. Edits are applied in order of start offset; edits with the same start offset are applied in they order they were provided.

Apply returns an error if any edit is out of bounds, or if any pair of edits is overlapping.

func SortEdits

func SortEdits(edits []Edit)

SortEdits orders a slice of Edits by (start, end) offset. This ordering puts insertions (end = start) before deletions (end > start) at the same point, but uses a stable sort to preserve the order of multiple insertions at the same point. (Apply detects multiple deletions at the same point as an error.)

func ToUnified

func ToUnified(oldLabel, newLabel, content string, edits []Edit) (string, error)

ToUnified applies the edits to content and returns a unified diff. The old and new labels are the names of the content and result files. It returns an error if the edits are inconsistent; see ApplyEdits.

func Unified

func Unified(oldLabel, newLabel, old, new string) string

Unified returns a unified diff of the old and new strings. The old and new labels are the names of the old and new files. If the strings are equal, it returns the empty string.

Types

type Edit

type Edit struct {
	Start, End int    // byte offsets of the region to replace
	New        string // the replacement
}

An Edit describes the replacement of a portion of a text file.

func Bytes

func Bytes(before, after []byte) []Edit

Bytes computes the differences between two byte slices. The resulting edits respect rune boundaries.

func Strings

func Strings(before, after string) []Edit

Strings computes the differences between two strings. The resulting edits respect rune boundaries.

type OpKind

type OpKind int

OpKind is used to denote the type of operation a line represents. TODO(adonovan): hide this once the myers package no longer references it.

const (
	// Delete is the operation kind for a line that is present in the input
	// but not in the output.
	Delete OpKind = iota
	// Insert is the operation kind for a line that is new in the output.
	Insert
	// Equal is the operation kind for a line that is the same in the input and
	// output, often used to provide context around edited lines.
	Equal
)

func (OpKind) String

func (k OpKind) String() string

String returns a human readable representation of an OpKind. It is not intended for machine processing.