jazz up Coord

.gitignore

@@ -1 +1,2 @@
 /build
+/release

day11.cpp

@@ -4,7 +4,7 @@
 #include <map>
 
 #include <intcode/intcode.hpp>
-#include <intcode/Grid.hpp>
+#include <intcode/Coord.hpp>
 using namespace intcode;
 
 namespace {
@@ -25,7 +25,7 @@ auto Compute(Machine machine, ValueType start)
         paint[here] = o;
       } else {
         dir = (o ? CW : CCW)(dir);
-        here = Add(here, dir);
+        here += dir;
       }
       next_color = !next_color;
     });

day13.cpp

@@ -4,7 +4,7 @@
 #include <set>
 
 #include <intcode/intcode.hpp>
-#include <intcode/Grid.hpp>
+#include <intcode/Coord.hpp>
 using namespace intcode;
 
 namespace {

day15.cpp

@@ -5,7 +5,7 @@
 #include <utility>
 
 #include <intcode/intcode.hpp>
-#include <intcode/Grid.hpp>
+#include <intcode/Coord.hpp>
 using namespace intcode;
 
 namespace {

lib/CMakeLists.txt

@@ -1,2 +1,2 @@
-add_library(intcode src/Grid.cpp src/Parser.cpp src/Interpreter.cpp src/Machine.cpp)
+add_library(intcode src/Coord.cpp src/Parser.cpp src/Interpreter.cpp src/Machine.cpp)
 target_include_directories(intcode PUBLIC include)

lib/include/intcode/Coord.hpp

@@ -0,0 +1,71 @@
+#ifndef INTCODE_COORD_HPP_
+#define INTCODE_COORD_HPP_
+
+#include <functional>
+#include <map>
+#include <ostream>
+#include <tuple>
+
+#include <intcode/Machine.hpp>
+
+namespace intcode {
+
+/// Cartesian coordinate
+///
+/// Coordinate where y grows down and x grows right
+struct Coord {
+  std::int64_t x, y;
+  auto operator<=>(const Coord&) const = default;
+};
+
+
+auto Draw(std::ostream & out, std::map<Coord, ValueType> image) -> void;
+
+/// Move one unit up
+auto Up(Coord) -> Coord;
+
+/// Move one unit down
+auto Down(Coord) -> Coord;
+
+/// Move one unit left
+auto Left(Coord) -> Coord;
+
+/// Move one unit right
+auto Right(Coord) -> Coord;
+
+/// Mirror coordinates about y=x line
+auto Invert(Coord) -> Coord;
+
+/// Rotate clockwise
+auto CW(Coord) -> Coord;
+
+/// Rotate counter-clockwise
+auto CCW(Coord) -> Coord;
+
+/// Add two coordinates pairwise
+auto operator+(Coord, Coord) -> Coord;
+
+/// Subtract two coordinates pairwise
+auto operator-(Coord, Coord) -> Coord;
+
+/// Compound assignment addition of coordinates
+auto operator+=(Coord &, Coord) -> Coord &;
+
+/// Compound assignment subtraction of coordinates
+auto operator-=(Coord &, Coord) -> Coord &;
+
+/// Write a coordinate to a string "(x,y)"
+auto operator<<(std::ostream &, Coord) -> std::ostream &;
+
+} // namespace
+
+template<>
+struct std::hash<intcode::Coord>
+{
+  auto operator()(intcode::Coord const& c) const noexcept -> std::size_t {
+    std::hash<std::int64_t> h;
+    return h(c.x) ^ h(c.y);
+  }
+};
+
+#endif

lib/include/intcode/Grid.hpp

@@ -1,27 +0,0 @@
-#ifndef INTCODE_GRID_HPP_
-#define INTCODE_GRID_HPP_
-
-#include <ostream>
-#include <map>
-#include <tuple>
-
-#include <intcode/Machine.hpp>
-
-namespace intcode {
-
-using Coord = std::pair<ValueType, ValueType>;
-
-auto Draw(std::ostream & out, std::map<Coord, ValueType> image) -> void;
-
-auto Up(Coord) -> Coord;
-auto Down(Coord) -> Coord;
-auto Left(Coord) -> Coord;
-auto Right(Coord) -> Coord;
-auto CW(Coord) -> Coord;
-auto CCW(Coord) -> Coord;
-auto Add(Coord, Coord) -> Coord;
-
-
-} // namespace
-
-#endif

lib/src/Coord.cpp

@@ -1,4 +1,4 @@
-#include <intcode/Grid.hpp>
+#include <intcode/Coord.hpp>
 
 namespace intcode {
 
@@ -30,39 +30,61 @@ auto Draw(std::ostream & out, std::map<Coord, ValueType> image) -> void {
 }
 
 auto Up(Coord c) -> Coord {
-  c.second -= 1;
+  c.y -= 1;
   return c;
 }
 
 auto Down(Coord c) -> Coord {
-  c.second += 1;
+  c.y += 1;
   return c;
 }
 
 auto Left(Coord c) -> Coord {
-  c.first -= 1;
+  c.x -= 1;
   return c;
 }
 
 auto Right(Coord c) -> Coord {
-  c.first += 1;
+  c.x += 1;
   return c;
 }
 
+auto Invert(Coord c) -> Coord {
+  return {c.y, c.x};
+}
+
 auto CW(Coord c) -> Coord {
-  std::swap(c.first, c.second);
-  c.first = -c.first;
+  c = Invert(c);
+  c.x = -c.x;
   return c;
 }
 
 auto CCW(Coord c) -> Coord {
-  std::swap(c.first, c.second);
-  c.second = -c.second;
+  c = Invert(c);
+  c.y = -c.y;
   return c;
 }
 
-auto Add(Coord x, Coord y) -> Coord {
-  return {x.first + y.first, x.second + y.second};
+auto operator+(Coord a, Coord b) -> Coord {
+  return {a.x + b.x, a.y + b.y};
+}
+
+auto operator-(Coord a, Coord b) -> Coord {
+  return {a.x - b.x, a.y - b.y};
+}
+
+auto operator+=(Coord & a, Coord b) -> Coord & {
+  a = a + b;
+  return a;
+}
+
+auto operator-=(Coord & a, Coord b) -> Coord & {
+  a = a - b;
+  return a;
+}
+
+auto operator<<(std::ostream & out, Coord c) -> std::ostream & {
+  return out << "(" << c.x << "," << c.y << ")";
 }
 
 } // namespace

lib/src/Interpreter.cpp

@@ -26,18 +26,12 @@ auto Step(Machine & m) -> std::variant<Input, Output, Halt> {
 
     switch (instruction % 100) {
     case 1: {
-      auto a = arg();
-      auto b = arg();
-      auto& c = arg();
-      c = a + b;
+      arg() = arg() + arg();
       break;
     }
 
     case 2: {
-      auto a = arg();
-      auto b = arg();
-      auto& c = arg();
-      c = a * b;
+      arg() = arg() * arg();
       break;
     }
 
@@ -66,16 +60,12 @@ auto Step(Machine & m) -> std::variant<Input, Output, Halt> {
     case 7: {
       auto a = arg();
       auto b = arg();
-      auto& c = arg();
-      c = a < b;
+      arg() = a < b; // order matters
       break;
     }
 
     case 8: {
-      auto a = arg();
-      auto b = arg();
-      auto& c = arg();
-      c = a == b;
+      arg() = arg() == arg();
       break;
     }