Add default basic constructor and operator!= to SelectionPosition to ease use.

Use default member initializer, constexpr for constructors and equality
operators and <, [[nodiscard]] for comparison operators.
Add simple unit tests for Selection. Not trying to be exhaustive here, just
start the process of adding tests.

2 files changed, 25 insertions, 26 deletions

diff --git a/src/Selection.cxx b/src/Selection.cxx
index 5b99b7c3a..ad63afd70 100644
--- a/src/Selection.cxx
+++ b/src/Selection.cxx
@@ -52,13 +52,6 @@ void SelectionPosition::MoveForInsertDelete(bool insertion, Sci::Position startC
 	}
 }
 
-bool SelectionPosition::operator <(const SelectionPosition &other) const noexcept {
-	if (position == other.position)
-		return virtualSpace < other.virtualSpace;
-	else
-		return position < other.position;
-}
-
 bool SelectionPosition::operator >(const SelectionPosition &other) const noexcept {
 	if (position == other.position)
 		return virtualSpace > other.virtualSpace;
diff --git a/src/Selection.h b/src/Selection.h
index c0d785870..7f3fd937b 100644
--- a/src/Selection.h
+++ b/src/Selection.h
@@ -11,10 +11,11 @@
 namespace Scintilla::Internal {
 
 class SelectionPosition {
-	Sci::Position position;
-	Sci::Position virtualSpace;
+	Sci::Position position = Sci::invalidPosition;
+	Sci::Position virtualSpace = 0;
 public:
-	explicit SelectionPosition(Sci::Position position_= Sci::invalidPosition, Sci::Position virtualSpace_=0) noexcept : position(position_), virtualSpace(virtualSpace_) {
+	constexpr SelectionPosition() noexcept = default;
+	constexpr explicit SelectionPosition(Sci::Position position_, Sci::Position virtualSpace_=0) noexcept : position(position_), virtualSpace(virtualSpace_) {
 		PLATFORM_ASSERT(virtualSpace < 800000000);
 		if (virtualSpace < 0)
 			virtualSpace = 0;
@@ -24,13 +25,20 @@ public:
 		virtualSpace = 0;
 	}
 	void MoveForInsertDelete(bool insertion, Sci::Position startChange, Sci::Position length, bool moveForEqual) noexcept;
-	bool operator ==(const SelectionPosition &other) const noexcept {
-		return position == other.position && virtualSpace == other.virtualSpace;
+	[[nodiscard]] constexpr bool operator ==(const SelectionPosition &other) const noexcept {
+		return (position == other.position) && (virtualSpace == other.virtualSpace);
 	}
-	bool operator <(const SelectionPosition &other) const noexcept;
-	bool operator >(const SelectionPosition &other) const noexcept;
-	bool operator <=(const SelectionPosition &other) const noexcept;
-	bool operator >=(const SelectionPosition &other) const noexcept;
+	[[nodiscard]] constexpr bool operator !=(const SelectionPosition &other) const noexcept {
+		return (position != other.position) || (virtualSpace != other.virtualSpace);
+	}
+	[[nodiscard]] constexpr bool operator <(const SelectionPosition &other) const noexcept {
+		if (position == other.position)
+			return virtualSpace < other.virtualSpace;
+		return position < other.position;
+	}
+	[[nodiscard]] bool operator >(const SelectionPosition &other) const noexcept;
+	[[nodiscard]] bool operator <=(const SelectionPosition &other) const noexcept;
+	[[nodiscard]] bool operator >=(const SelectionPosition &other) const noexcept;
 	Sci::Position Position() const noexcept {
 		return position;
 	}
@@ -61,9 +69,8 @@ public:
 struct SelectionSegment {
 	SelectionPosition start;
 	SelectionPosition end;
-	SelectionSegment() noexcept : start(), end() {
-	}
-	SelectionSegment(SelectionPosition a, SelectionPosition b) noexcept {
+	constexpr SelectionSegment() noexcept = default;
+	constexpr SelectionSegment(SelectionPosition a, SelectionPosition b) noexcept {
 		if (a < b) {
 			start = a;
 			end = b;
@@ -96,15 +103,14 @@ struct SelectionRange {
 	SelectionPosition caret;
 	SelectionPosition anchor;
 
-	SelectionRange() noexcept : caret(), anchor() {
-	}
-	explicit SelectionRange(SelectionPosition single) noexcept : caret(single), anchor(single) {
+	constexpr SelectionRange() noexcept = default;
+	constexpr explicit SelectionRange(SelectionPosition single) noexcept : caret(single), anchor(single) {
 	}
-	explicit SelectionRange(Sci::Position single) noexcept : caret(single), anchor(single) {
+	constexpr explicit SelectionRange(Sci::Position single) noexcept : caret(single), anchor(single) {
 	}
-	SelectionRange(SelectionPosition caret_, SelectionPosition anchor_) noexcept : caret(caret_), anchor(anchor_) {
+	constexpr SelectionRange(SelectionPosition caret_, SelectionPosition anchor_) noexcept : caret(caret_), anchor(anchor_) {
 	}
-	SelectionRange(Sci::Position caret_, Sci::Position anchor_) noexcept : caret(caret_), anchor(anchor_) {
+	constexpr SelectionRange(Sci::Position caret_, Sci::Position anchor_) noexcept : caret(caret_), anchor(anchor_) {
 	}
 	bool Empty() const noexcept {
 		return anchor == caret;
@@ -158,7 +164,7 @@ public:
 	enum class SelTypes { none, stream, rectangle, lines, thin };
 	SelTypes selType;
 
-	Selection();
+	Selection();	// Allocates so may throw.
 	bool IsRectangular() const noexcept;
 	Sci::Position MainCaret() const noexcept;
 	Sci::Position MainAnchor() const noexcept;