newedit/core: Highlighter.LateUpdates also deliver styled.Text.

Although the result is not used, it makes Highlighter.LateUpdates and
Prompt.LateUpdates identical.

newedit/core/editor.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/elves/elvish/edit/tty"
 	"github.com/elves/elvish/newedit/types"
+	"github.com/elves/elvish/styled"
 	"github.com/elves/elvish/sys"
 )
 
@@ -198,20 +199,16 @@ func (ed *Editor) ReadCode() (string, error) {
 		}()
 	}
 
+	// Relay late updates from prompt, rprompt and highlighter.
 	stopRelayLateUpdates := make(chan struct{})
 	defer close(stopRelayLateUpdates)
-
-	// Relay late prompt/rprompt updates.
-	relayLateUpdates := func(p Prompt) {
-		if p == nil {
-			return
-		}
+	relayLateUpdates := func(ch <-chan styled.Text) {
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
 			for {
 				select {
-				case <-p.LateUpdates():
+				case <-ch:
 					ed.loop.Input(lateUpdate{})
 				case <-stopRelayLateUpdates:
 					return
@@ -219,23 +216,14 @@ func (ed *Editor) ReadCode() (string, error) {
 			}
 		}()
 	}
-	relayLateUpdates(ed.Prompt)
-	relayLateUpdates(ed.RPrompt)
-
-	// Relay highlighter late updates.
+	if ed.Prompt != nil {
+		relayLateUpdates(ed.Prompt.LateUpdates())
+	}
+	if ed.RPrompt != nil {
+		relayLateUpdates(ed.RPrompt.LateUpdates())
+	}
 	if ed.Highlighter != nil {
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
-			for {
-				select {
-				case <-ed.Highlighter.LateUpdates():
-					ed.loop.Input(lateUpdate{})
-				case <-stopRelayLateUpdates:
-					return
-				}
-			}
-		}()
+		relayLateUpdates(ed.Highlighter.LateUpdates())
 	}
 
 	// Trigger an initial prompt update.

newedit/core/highlighter.go

@@ -7,8 +7,8 @@ import "github.com/elves/elvish/styled"
 type Highlighter interface {
 	// Get returns the highlighted code and any static errors.
 	Get(code string) (styled.Text, []error)
-	// LateUpdates returns a channel for notifying late updates.
-	LateUpdates() <-chan struct{}
+	// LateUpdates returns a channel for delivering late updates.
+	LateUpdates() <-chan styled.Text
 }
 
 func highlighterGet(hl Highlighter, code string) (styled.Text, []error) {
@@ -21,13 +21,13 @@ func highlighterGet(hl Highlighter, code string) (styled.Text, []error) {
 // A Highlighter implementation useful for testing.
 type fakeHighlighter struct {
 	get         func(code string) (styled.Text, []error)
-	lateUpdates chan struct{}
+	lateUpdates chan styled.Text
 }
 
 func (hl fakeHighlighter) Get(code string) (styled.Text, []error) {
 	return hl.get(code)
 }
 
-func (hl fakeHighlighter) LateUpdates() <-chan struct{} {
+func (hl fakeHighlighter) LateUpdates() <-chan styled.Text {
 	return hl.lateUpdates
 }

newedit/highlight/highlighter.go

@@ -12,7 +12,7 @@ const latesBufferSize = 128
 type Highlighter struct {
 	dep   Dep
 	state state
-	lates chan struct{}
+	lates chan styled.Text
 }
 
 type state struct {
@@ -23,7 +23,7 @@ type state struct {
 }
 
 func NewHighlighter(dep Dep) *Highlighter {
-	return &Highlighter{dep, state{}, make(chan struct{}, latesBufferSize)}
+	return &Highlighter{dep, state{}, make(chan styled.Text, latesBufferSize)}
 }
 
 // Get returns the highlighted code and static errors found in the code.
@@ -39,12 +39,12 @@ func (hl *Highlighter) Get(code string) (styled.Text, []error) {
 		hl.state.Lock()
 		hl.state.styledCode = styledCode
 		hl.state.Unlock()
-		hl.lates <- struct{}{}
+		hl.lates <- styledCode
 	}
 	return highlight(code, hl.dep, lateCb)
 }
 
 // LateUpdates returns a channel for notifying late updates.
-func (hl *Highlighter) LateUpdates() <-chan struct{} {
+func (hl *Highlighter) LateUpdates() <-chan styled.Text {
 	return hl.lates
 }