difflib

Go-difflib is a partial port of Python 3 difflib package. Its main goal is to make unified and context diff available in pure Go, mostly for testing purposes.

The following class and functions (and related tests) have been ported:

• SequenceMatcher: Struct containing some methods to compares sequence of strings.

• unified_diff(): Compare A and B (array of strings) and return a generator generating the output lines in unified diff format. Unified diffs are a compact way of showing just the lines that have changed plus a few lines of context. The changes are shown in an inline style (instead of separate before/after blocks).

• context_diff(): Compare A and B (array of strings) and return a generator generating the output lines in context diff format. Context diffs are a compact way of showing just the lines that have changed plus a few lines of context. The changes are shown in a before/after style.

You can also have the output in colors by enabling the WithColors parameter (only for unified diff for the moment).

Installation

$ go get github.com/Scalingo/go-utils/difflib

Quick Start

Diffs are configured with Unified (or ContextDiff) structures, and can be output to an io.Writer or returned as a string.

diff := difflib.UnifiedDiff{
    A:        difflib.SplitLines("foo\nbar\n"),
    B:        difflib.SplitLines("foo\nbaz\n"),
    FromFile: "Original",
    ToFile:   "Current",
    Context:  3,
    WithColors: false
}
text, _ := difflib.GetUnifiedDiffString(diff)
fmt.Printf(text)

Would output:

--- Original
+++ Current
@@ -1,3 +1,3 @@
 foo
-bar
+baz