Simplify some implementations of operator< using lexicographical tuple comparison

Might do operator== later too.

src/font/font_id.hpp

@@ -19,6 +19,8 @@
 #pragma once
 
 #include <string>
+#include <tuple>
+
 #include <SDL_ttf.h>
 
 /***
@@ -42,7 +44,7 @@ struct font_id
 	}
 	bool operator<(const font_id& o) const
 	{
-		return subset < o.subset || (subset == o.subset && size < o.size) || (subset == o.subset && size == o.size && style < o.style);
+		return std::tie(subset, size, style) < std::tie(o.subset, o.size, o.style);
 	}
 
 	subset_id subset;

src/gui/dialogs/multiplayer/mp_options_helper.hpp

@@ -50,8 +50,9 @@ private:
 		std::string level_type;
 		std::string id;
 
-		friend bool operator<(const option_source& a, const option_source& b) {
-			return a.level_type < b.level_type || (a.level_type == b.level_type && a.id < b.id);
+		friend bool operator<(const option_source& a, const option_source& b)
+		{
+			return std::tie(a.level_type, a.id) < std::tie(b.level_type, b.id);
 		}
 	};
 

src/gui/widgets/minimap.cpp

@@ -89,10 +89,7 @@ struct key_type
 
 static bool operator<(const key_type& lhs, const key_type& rhs)
 {
-	return lhs.w < rhs.w
-		   || (lhs.w == rhs.w
-			   && (lhs.h < rhs.h
-				   || (lhs.h == rhs.h && lhs.map_data < rhs.map_data)));
+	return std::tie(lhs.w, lhs.h, lhs.map_data) < std::tie(rhs.w, rhs.h, rhs.map_data);
 }
 
 /** Value type for the cache. */

src/map/location.hpp

@@ -24,6 +24,7 @@ class variable_set;
 #include <cstdlib>
 #include <set>
 #include <string>
+#include <tuple>
 #include <vector>
 #include <algorithm>
 #include <utility>
@@ -81,7 +82,7 @@ struct map_location {
 	bool matches_range(const std::string& xloc, const std::string& yloc) const;
 
 	// Inlining those for performance reasons
-	bool operator<(const map_location& a) const { return x < a.x || (x == a.x && y < a.y); }
+	bool operator<(const map_location& a) const { return std::tie(x, y) < std::tie(a.x, a.y); }
 	bool operator==(const map_location& a) const { return x == a.x && y == a.y; }
 	bool operator!=(const map_location& a) const { return !operator==(a); }
 

src/pathfind/pathfind.cpp

@@ -180,9 +180,9 @@ namespace {
 		{ }
 
 		// Compare these nodes based on movement consumed.
-		bool operator<(const findroute_node& o) const {
-			return turns_left > o.turns_left ||
-				  (turns_left == o.turns_left && moves_left > o.moves_left);
+		bool operator<(const findroute_node& o) const
+		{
+			return std::tie(turns_left, moves_left) > std::tie(o.turns_left, o.moves_left);
 		}
 	};
 

src/sdl/point.hpp

@@ -17,6 +17,7 @@
 #include <SDL_rect.h>
 
 #include <iosfwd>
+#include <tuple>
 
 /** Holds a 2D point. */
 struct point
@@ -60,7 +61,7 @@ struct point
 
 	bool operator<(const point& point) const
 	{
-		return x < point.x || (x == point.x && y < point.y);
+		return std::tie(x, y) < std::tie(point.x, point.y);
 	}
 
 	bool operator<=(const point& point) const

src/terrain/builder.hpp

@@ -353,7 +353,7 @@ public:
 			/** sort by layer first then by basey */
 			bool operator<(const rule_image_rand& o) const
 			{
-				return ri->layer < o.ri->layer || (ri->layer == o.ri->layer && ri->basey < o.ri->basey);
+				return std::tie(ri->layer, ri->basey) < std::tie(o.ri->layer, o.ri->basey);
 			}
 
 			const rule_image* ri;

src/terrain/translation.hpp

@@ -64,7 +64,7 @@ namespace t_translation {
 	const terrain_code NONE_TERRAIN = terrain_code();
 
 	inline bool operator<(const terrain_code& a, const terrain_code& b)
-		{ return a.base < b.base ||  (a.base == b.base && a.overlay < b.overlay); }
+		{ return std::tie(a.base, a.overlay) < std::tie(b.base, b.overlay); };
 
 	inline bool operator==(const terrain_code& a, const terrain_code& b)
 		{ return a.base == b.base && a.overlay == b.overlay; }