Merge pull request #140 from odino/master

Added OptionBreakLineCallback, to run a callback every time there's a line break

go.mod

@@ -6,5 +6,5 @@ require (
 	github.com/mattn/go-runewidth v0.0.3
 	github.com/mattn/go-tty v0.0.0-20180219170247-931426f7535a
 	github.com/pkg/term v0.0.0-20180423043932-cda20d4ac917
-	golang.org/x/sys v0.0.0-20180620133508-ad87a3a340fa // indirect
+	golang.org/x/sys v0.0.0-20180620133508-ad87a3a340fa
 )

option.go

@@ -234,6 +234,14 @@ func OptionShowCompletionAtStart() Option {
 	}
 }
 
+// OptionBreakLineCallback to run a callback at every break line
+func OptionBreakLineCallback(fn func(*Document)) Option {
+	return func(p *Prompt) error {
+		p.renderer.breakLineCallback = fn
+		return nil
+	}
+}
+
 // New returns a Prompt with powerful auto-completion.
 func New(executor Executor, completer Completer, opts ...Option) *Prompt {
 	defaultWriter := NewStdoutWriter()

render.go

@@ -12,6 +12,7 @@ type Render struct {
 	out                ConsoleWriter
 	prefix             string
 	livePrefixCallback func() (prefix string, useLivePrefix bool)
+	breakLineCallback  func(*Document)
 	title              string
 	row                uint16
 	col                uint16
@@ -235,6 +236,9 @@ func (r *Render) BreakLine(buffer *Buffer) {
 	r.out.WriteStr(buffer.Document().Text + "\n")
 	r.out.SetColor(DefaultColor, DefaultColor, false)
 	debug.AssertNoError(r.out.Flush())
+	if r.breakLineCallback != nil {
+		r.breakLineCallback(buffer.Document())
+	}
 
 	r.previousCursor = 0
 }

render_test.go

@@ -2,6 +2,7 @@ package prompt
 
 import (
 	"reflect"
+	"syscall"
 	"testing"
 )
 
@@ -65,3 +66,48 @@ func TestFormatCompletion(t *testing.T) {
 		}
 	}
 }
+
+func TestBreakLineCallback(t *testing.T) {
+	var i int
+	r := &Render{
+		prefix: "> ",
+		out: &PosixWriter{
+			fd: syscall.Stdin, // "write" to stdin just so we don't mess with the output of the tests
+		},
+		livePrefixCallback:           func() (string, bool) { return "", false },
+		prefixTextColor:              Blue,
+		prefixBGColor:                DefaultColor,
+		inputTextColor:               DefaultColor,
+		inputBGColor:                 DefaultColor,
+		previewSuggestionTextColor:   Green,
+		previewSuggestionBGColor:     DefaultColor,
+		suggestionTextColor:          White,
+		suggestionBGColor:            Cyan,
+		selectedSuggestionTextColor:  Black,
+		selectedSuggestionBGColor:    Turquoise,
+		descriptionTextColor:         Black,
+		descriptionBGColor:           Turquoise,
+		selectedDescriptionTextColor: White,
+		selectedDescriptionBGColor:   Cyan,
+		scrollbarThumbColor:          DarkGray,
+		scrollbarBGColor:             Cyan,
+		col:                          1,
+	}
+	b := NewBuffer()
+	r.BreakLine(b)
+
+	if i != 0 {
+		t.Errorf("i should initially be 0, before applying a break line callback")
+	}
+
+	r.breakLineCallback = func(doc *Document) {
+		i++
+	}
+	r.BreakLine(b)
+	r.BreakLine(b)
+	r.BreakLine(b)
+
+	if i != 3 {
+		t.Errorf("BreakLine callback not called, i should be 3")
+	}
+}