After commit c018f5fd29 Fenrir is being switched over to go. If you do not want to be part of the testing process, please switch to master.

internal/reader/indentation.go

@@ -0,0 +1,64 @@
+// Copyright (c) 2026 Storm Dragon
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package reader
+
+import (
+	"slices"
+	"strings"
+	"time"
+	"unicode"
+
+	"git.stormux.org/storm/fenrir/internal/presentation"
+	"git.stormux.org/storm/fenrir/internal/screen"
+)
+
+func (r *Reader) Configure_indentation(mode string) { r.indentationMode = mode }
+
+func (r *Reader) indentation_feedback(announce bool) *presentation.Message {
+	level, valid := r.review.Indentation()
+	if !valid {
+		return nil // Blank rows preserve the last meaningful level.
+	}
+	changed := r.indentKnown && level != r.lastIndent
+	r.lastIndent, r.indentKnown = level, true
+	if !announce || !changed || r.indentationMode == "" || r.indentationMode == "none" {
+		return nil
+	}
+	message := presentation.Indentation_message(level, r.indentationMode)
+	return &message
+}
+
+func (r *Reader) automatic_indentation(previous, next screen.Snapshot, switched bool) *presentation.Message {
+	if switched {
+		r.indentKnown = false
+	}
+	// Passive program output must not create indentation chatter. Match Python's
+	// cursor-input window and suppress automatic cursor feedback during review.
+	announce := !switched && next.Active && r.automatic && r.cursorEcho && r.trackingMode == "cursor" && !r.review.Active() &&
+		r.region_state().allows(next.X, next.Y, next.Cols, true, true) &&
+		!r.applicationInputAt.IsZero() && time.Since(r.applicationInputAt) < 300*time.Millisecond
+	if announce {
+		// A hidden leading-whitespace edit must not produce indentation cues
+		// at an otherwise visible cursor farther along the same row.
+		for col, char := range next.Line(next.Y) {
+			if !r.region_state().allows(col, next.Y, next.Cols, true, true) {
+				announce = false
+				break
+			}
+			if !unicode.IsSpace(char) {
+				break
+			}
+		}
+	}
+	if announce && previous.Y == next.Y {
+		// Horizontal input only reports a genuine leading-whitespace edit, not
+		// movement within a line or ordinary typing/deletion in its content.
+		before, after := previous.Text(previous.Y), next.Text(next.Y)
+		announce = strings.TrimSpace(before) == strings.TrimSpace(after) && before != after
+	} else if announce {
+		// A cursor moving with new program output is not line navigation.
+		announce = slices.Equal(previous.Line(next.Y), next.Line(next.Y))
+	}
+	return r.indentation_feedback(announce)
+}