Extract key code from HorizontalMove to shorten and simplify it.

New methods are SelectionMove, PositionMove, HomeWrapPosition and
SelectionPosition::AddVirtualSpace.
This refactoring commit does not change behaviour.

3 files changed, 134 insertions, 146 deletions

diff --git a/src/Editor.cxx b/src/Editor.cxx
index 7d4417115..ade5094f7 100644
--- a/src/Editor.cxx
+++ b/src/Editor.cxx
@@ -3442,6 +3442,14 @@ constexpr bool IsRectExtend(Message iMessage, bool isRectMoveExtends) noexcept {
 
 }
 
+Sci::Position Editor::HomeWrapPosition(Sci::Position position) {
+	const Sci::Position viewLineStart = StartEndDisplayLine(position, true);
+	const Sci::Position homePos = MovePositionSoVisible(viewLineStart, -1).Position();
+	if (position <= homePos)
+		return pdoc->LineStartPosition(position);
+	return homePos;
+}
+
 Sci::Position Editor::VCHomeDisplayPosition(Sci::Position position) {
 	const Sci::Position homePos = pdoc->VCHomePosition(position);
 	const Sci::Position viewLineStart = StartEndDisplayLine(position, true);
@@ -3470,6 +3478,125 @@ Sci::Position Editor::LineEndWrapPosition(Sci::Position position) {
 		return endPos;
 }
 
+SelectionPosition Editor::PositionMove(Message iMessage, SelectionPosition spCaret) {
+	switch (iMessage) {
+	case Message::CharLeft:
+	case Message::CharLeftExtend:
+		if (spCaret.VirtualSpace()) {
+			spCaret.AddVirtualSpace(-1);
+		} else if (!FlagSet(virtualSpaceOptions, VirtualSpace::NoWrapLineStart) || pdoc->GetColumn(spCaret.Position()) > 0) {
+			spCaret.Add(-1);
+		}
+		return spCaret;
+	case Message::CharRight:
+	case Message::CharRightExtend:
+		if (FlagSet(virtualSpaceOptions, VirtualSpace::UserAccessible) && pdoc->IsLineEndPosition(spCaret.Position())) {
+			spCaret.AddVirtualSpace(1);
+		} else {
+			spCaret.Add(1);
+		}
+		return spCaret;
+	case Message::WordLeft:
+	case Message::WordLeftExtend:
+		return SelectionPosition(pdoc->NextWordStart(spCaret.Position(), -1));
+	case Message::WordRight:
+	case Message::WordRightExtend:
+		return SelectionPosition(pdoc->NextWordStart(spCaret.Position(), 1));
+	case Message::WordLeftEnd:
+	case Message::WordLeftEndExtend:
+		return SelectionPosition(pdoc->NextWordEnd(spCaret.Position(), -1));
+	case Message::WordRightEnd:
+	case Message::WordRightEndExtend:
+		return SelectionPosition(pdoc->NextWordEnd(spCaret.Position(), 1));
+	case Message::WordPartLeft:
+	case Message::WordPartLeftExtend:
+		return SelectionPosition(pdoc->WordPartLeft(spCaret.Position()));
+	case Message::WordPartRight:
+	case Message::WordPartRightExtend:
+		return SelectionPosition(pdoc->WordPartRight(spCaret.Position()));
+	case Message::Home:
+	case Message::HomeExtend:
+		return SelectionPosition(pdoc->LineStartPosition(spCaret.Position()));
+	case Message::HomeDisplay:
+	case Message::HomeDisplayExtend:
+		return SelectionPosition(StartEndDisplayLine(spCaret.Position(), true));
+	case Message::HomeWrap:
+	case Message::HomeWrapExtend:
+		return SelectionPosition(HomeWrapPosition(spCaret.Position()));
+	case Message::VCHome:
+	case Message::VCHomeExtend:
+		// VCHome alternates between beginning of line and beginning of text so may move back or forwards
+		return SelectionPosition(pdoc->VCHomePosition(spCaret.Position()));
+	case Message::VCHomeDisplay:
+	case Message::VCHomeDisplayExtend:
+		return SelectionPosition(VCHomeDisplayPosition(spCaret.Position()));
+	case Message::VCHomeWrap:
+	case Message::VCHomeWrapExtend:
+		return SelectionPosition(VCHomeWrapPosition(spCaret.Position()));
+	case Message::LineEnd:
+	case Message::LineEndExtend:
+		return SelectionPosition(pdoc->LineEndPosition(spCaret.Position()));
+	case Message::LineEndDisplay:
+	case Message::LineEndDisplayExtend:
+		return SelectionPosition(StartEndDisplayLine(spCaret.Position(), false));
+	case Message::LineEndWrap:
+	case Message::LineEndWrapExtend:
+		return SelectionPosition(LineEndWrapPosition(spCaret.Position()));
+
+	default:
+		break;
+	}
+	// Above switch should be exhaustive so this will never be reached.
+	PLATFORM_ASSERT(false);
+	return spCaret;
+}
+
+SelectionRange Editor::SelectionMove(Scintilla::Message iMessage, size_t r) {
+	const SelectionPosition spCaretStart = sel.Range(r).caret;
+	const SelectionPosition spCaretMoved = PositionMove(iMessage, spCaretStart);
+
+	const int directionMove = (spCaretMoved < spCaretStart) ? -1 : 1;
+	const SelectionPosition spCaret = MovePositionSoVisible(spCaretMoved, directionMove);
+
+	// Handle move versus extend, and special behaviour for non-empty left/right
+	switch (iMessage) {
+	case Message::CharLeft:
+	case Message::CharRight:
+		if (sel.Range(r).Empty()) {
+			return SelectionRange(spCaret);
+		}
+		if (iMessage == Message::CharLeft) {
+			return SelectionRange(sel.Range(r).Start());
+		}
+		return SelectionRange(sel.Range(r).End());
+
+	case Message::WordLeft:
+	case Message::WordRight:
+	case Message::WordLeftEnd:
+	case Message::WordRightEnd:
+	case Message::WordPartLeft:
+	case Message::WordPartRight:
+	case Message::Home:
+	case Message::HomeDisplay:
+	case Message::HomeWrap:
+	case Message::VCHome:
+	case Message::VCHomeDisplay:
+	case Message::VCHomeWrap:
+	case Message::LineEnd:
+	case Message::LineEndDisplay:
+	case Message::LineEndWrap:
+		return SelectionRange(spCaret);
+
+	default:
+		break;
+	}
+
+	// All remaining cases are *Extend
+	const SelectionRange rangeNew = SelectionRange(spCaret, sel.Range(r).anchor);
+	sel.TrimOtherSelections(r, rangeNew);
+	return rangeNew;
+}
+
 int Editor::HorizontalMove(Message iMessage) {
 	if (sel.selType == Selection::SelTypes::lines) {
 		return 0; // horizontal moves with line selection have no effect
@@ -3554,152 +3681,7 @@ int Editor::HorizontalMove(Message iMessage) {
 			sel.DropAdditionalRanges();
 		}
 		for (size_t r = 0; r < sel.Count(); r++) {
-			const SelectionPosition spCaretNow = sel.Range(r).caret;
-			SelectionPosition spCaret = spCaretNow;
-			switch (iMessage) {
-			case Message::CharLeft:
-			case Message::CharLeftExtend:
-				if (spCaret.VirtualSpace()) {
-					spCaret.SetVirtualSpace(spCaret.VirtualSpace() - 1);
-				} else if (!FlagSet(virtualSpaceOptions, VirtualSpace::NoWrapLineStart) || pdoc->GetColumn(spCaret.Position()) > 0) {
-					spCaret = SelectionPosition(spCaret.Position() - 1);
-				}
-				break;
-			case Message::CharRight:
-			case Message::CharRightExtend:
-				if (FlagSet(virtualSpaceOptions, VirtualSpace::UserAccessible) && pdoc->IsLineEndPosition(spCaret.Position())) {
-					spCaret.SetVirtualSpace(spCaret.VirtualSpace() + 1);
-				} else {
-					spCaret = SelectionPosition(spCaret.Position() + 1);
-				}
-				break;
-			case Message::WordLeft:
-			case Message::WordLeftExtend:
-				spCaret = SelectionPosition(pdoc->NextWordStart(spCaret.Position(), -1));
-				break;
-			case Message::WordRight:
-			case Message::WordRightExtend:
-				spCaret = SelectionPosition(pdoc->NextWordStart(spCaret.Position(), 1));
-				break;
-			case Message::WordLeftEnd:
-			case Message::WordLeftEndExtend:
-				spCaret = SelectionPosition(pdoc->NextWordEnd(spCaret.Position(), -1));
-				break;
-			case Message::WordRightEnd:
-			case Message::WordRightEndExtend:
-				spCaret = SelectionPosition(pdoc->NextWordEnd(spCaret.Position(), 1));
-				break;
-			case Message::WordPartLeft:
-			case Message::WordPartLeftExtend:
-				spCaret = SelectionPosition(pdoc->WordPartLeft(spCaret.Position()));
-				break;
-			case Message::WordPartRight:
-			case Message::WordPartRightExtend:
-				spCaret = SelectionPosition(pdoc->WordPartRight(spCaret.Position()));
-				break;
-			case Message::Home:
-			case Message::HomeExtend:
-				spCaret = SelectionPosition(pdoc->LineStartPosition(spCaret.Position()));
-				break;
-			case Message::HomeDisplay:
-			case Message::HomeDisplayExtend:
-				spCaret = SelectionPosition(StartEndDisplayLine(spCaret.Position(), true));
-				break;
-			case Message::HomeWrap:
-			case Message::HomeWrapExtend:
-				spCaret = MovePositionSoVisible(StartEndDisplayLine(spCaret.Position(), true), -1);
-				if (spCaretNow <= spCaret)
-					spCaret = SelectionPosition(pdoc->LineStartPosition(spCaret.Position()));
-				break;
-			case Message::VCHome:
-			case Message::VCHomeExtend:
-				// VCHome alternates between beginning of line and beginning of text so may move back or forwards
-				spCaret = SelectionPosition(pdoc->VCHomePosition(spCaret.Position()));
-				break;
-			case Message::VCHomeDisplay:
-			case Message::VCHomeDisplayExtend:
-				spCaret = SelectionPosition(VCHomeDisplayPosition(spCaret.Position()));
-				break;
-			case Message::VCHomeWrap:
-			case Message::VCHomeWrapExtend:
-				spCaret = SelectionPosition(VCHomeWrapPosition(spCaret.Position()));
-				break;
-			case Message::LineEnd:
-			case Message::LineEndExtend:
-				spCaret = SelectionPosition(pdoc->LineEndPosition(spCaret.Position()));
-				break;
-			case Message::LineEndDisplay:
-			case Message::LineEndDisplayExtend:
-				spCaret = SelectionPosition(StartEndDisplayLine(spCaret.Position(), false));
-				break;
-			case Message::LineEndWrap:
-			case Message::LineEndWrapExtend:
-				spCaret = SelectionPosition(LineEndWrapPosition(spCaret.Position()));
-				break;
-
-			default:
-				PLATFORM_ASSERT(false);
-			}
-
-			const int directionMove = (spCaret < spCaretNow) ? -1 : 1;
-			spCaret = MovePositionSoVisible(spCaret, directionMove);
-
-			// Handle move versus extend, and special behaviour for non-empty left/right
-			switch (iMessage) {
-			case Message::CharLeft:
-			case Message::CharRight:
-				if (sel.Range(r).Empty()) {
-					sel.Range(r) = SelectionRange(spCaret);
-				} else {
-					sel.Range(r) = SelectionRange(
-						(iMessage == Message::CharLeft) ? sel.Range(r).Start() : sel.Range(r).End());
-				}
-				break;
-
-			case Message::WordLeft:
-			case Message::WordRight:
-			case Message::WordLeftEnd:
-			case Message::WordRightEnd:
-			case Message::WordPartLeft:
-			case Message::WordPartRight:
-			case Message::Home:
-			case Message::HomeDisplay:
-			case Message::HomeWrap:
-			case Message::VCHome:
-			case Message::VCHomeDisplay:
-			case Message::VCHomeWrap:
-			case Message::LineEnd:
-			case Message::LineEndDisplay:
-			case Message::LineEndWrap:
-				sel.Range(r) = SelectionRange(spCaret);
-				break;
-
-			case Message::CharLeftExtend:
-			case Message::CharRightExtend:
-			case Message::WordLeftExtend:
-			case Message::WordRightExtend:
-			case Message::WordLeftEndExtend:
-			case Message::WordRightEndExtend:
-			case Message::WordPartLeftExtend:
-			case Message::WordPartRightExtend:
-			case Message::HomeExtend:
-			case Message::HomeDisplayExtend:
-			case Message::HomeWrapExtend:
-			case Message::VCHomeExtend:
-			case Message::VCHomeDisplayExtend:
-			case Message::VCHomeWrapExtend:
-			case Message::LineEndExtend:
-			case Message::LineEndDisplayExtend:
-			case Message::LineEndWrapExtend: {
-				SelectionRange rangeNew = SelectionRange(spCaret, sel.Range(r).anchor);
-				sel.TrimOtherSelections(r, SelectionRange(rangeNew));
-				sel.Range(r) = rangeNew;
-				}
-				break;
-
-			default:
-				PLATFORM_ASSERT(false);
-			}
+			sel.Range(r) = SelectionMove(iMessage, r);
 		}
 	}
 
diff --git a/src/Editor.h b/src/Editor.h
index 54ca1110f..8c6458879 100644
--- a/src/Editor.h
+++ b/src/Editor.h
@@ -491,9 +491,12 @@ protected:	// ScintillaBase subclass needs access to much of Editor
 	void ParaUpOrDown(int direction, Selection::SelTypes selt);
 	Range RangeDisplayLine(Sci::Line lineVisible);
 	Sci::Position StartEndDisplayLine(Sci::Position pos, bool start);
+	Sci::Position HomeWrapPosition(Sci::Position position);
 	Sci::Position VCHomeDisplayPosition(Sci::Position position);
 	Sci::Position VCHomeWrapPosition(Sci::Position position);
 	Sci::Position LineEndWrapPosition(Sci::Position position);
+	SelectionPosition PositionMove(Scintilla::Message iMessage, SelectionPosition spCaretNow);
+	SelectionRange SelectionMove(Scintilla::Message iMessage, size_t r);
 	int HorizontalMove(Scintilla::Message iMessage);
 	int DelWordOrLine(Scintilla::Message iMessage);
 	virtual int KeyCommand(Scintilla::Message iMessage);
diff --git a/src/Selection.h b/src/Selection.h
index bc0f2208a..30e1e27ad 100644
--- a/src/Selection.h
+++ b/src/Selection.h
@@ -49,6 +49,9 @@ public:
 	void Add(Sci::Position increment) noexcept {
 		position = position + increment;
 	}
+	void AddVirtualSpace(Sci::Position increment) noexcept {
+		SetVirtualSpace(virtualSpace + increment);
+	}
 	bool IsValid() const noexcept {
 		return position >= 0;
 	}