From 74052ef2bfd4f470a4983c0f873498504252fe99 Mon Sep 17 00:00:00 2001
From: Arthur O'Dwyer <arthur.j.odwyer@gmail.com>
Date: Sun, 18 Jul 2021 17:02:52 -0400
Subject: [PATCH] Replace IF_KEY_EXISTS with a plain old function, not a macro.

---
 graph.cpp |  2 +-
 hyper.h   | 12 +++++++-----
 util.cpp  | 14 +++++++-------
 3 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/graph.cpp b/graph.cpp
index d0d601a2..2cb48666 100644
--- a/graph.cpp
+++ b/graph.cpp
@@ -45,7 +45,7 @@ EX bool hide_player() {
      ;
   }
 
-#define ADC(V,c) IF_KEY_EXISTS(it, current_display->all_drawn_copies, c) for(const shiftmatrix& V: it->second)
+#define ADC(V,c) if (auto *it = hr::find_or_null(current_display->all_drawn_copies, c)) for(const shiftmatrix& V: it->second)
 
 EX hookset<bool(int sym, int uni)> hooks_handleKey;
 EX hookset<bool(cell *c, const shiftmatrix& V)> hooks_drawcell;
diff --git a/hyper.h b/hyper.h
index 3c43b595..ddac8031 100644
--- a/hyper.h
+++ b/hyper.h
@@ -575,11 +575,6 @@ typedef function<int(struct cell*)> cellfunction;
 #define forCellCM(ct, cf) forCellIdCM(ct,forCellCM ## __LINE__,cf)
 #define forCellAll(ct, cf) forCellIdCM(ct,forCellAll ## __LINE__,cf)
 
-/* conditions */
-
-/** `IF_KEY_EXISTS(it, map, key) statement` checks whether the map 'map' contain key 'key', and if so, executes statement with it set to the relevant iterator */
-#define IF_KEY_EXISTS(it, map, key) for(auto it: {map.find(key)}) if(it != map.end())
-
 // canAttack/moveval flags
 
 #define AF_NORMAL            0          // nothing special about this attack
@@ -851,6 +846,13 @@ template<class T> array<T, 4> make_array(T a, T b, T c, T d) { array<T,4> x; x[0
 template<class T> array<T, 3> make_array(T a, T b, T c) { array<T,3> x; x[0] = a; x[1] = b; x[2] = c; return x; }
 template<class T> array<T, 2> make_array(T a, T b) { array<T,2> x; x[0] = a; x[1] = b; return x; }
 
+// Find in a std::map or std::unordered_map, or return null.
+template<class Map, class Key>
+const typename Map::value_type *find_or_null(const Map& map, const Key& key) {
+  auto it = map.find(key);
+  return (it == map.end()) ? nullptr : &*it;
+  }
+
 namespace daily {
   extern bool on;
   extern int daily_id;
diff --git a/util.cpp b/util.cpp
index f98e7d60..9072203d 100644
--- a/util.cpp
+++ b/util.cpp
@@ -207,7 +207,7 @@ cld exp_parser::parse(int prio) {
     cld c = rparse(0);
     force_eat(")");
 
-    IF_KEY_EXISTS(it, extra_params, "angleunit") {
+    if (auto *it = hr::find_or_null(extra_params, "angleunit")) {
       a *= it->second;
       b *= it->second;
       c *= it->second;
@@ -237,13 +237,13 @@ cld exp_parser::parse(int prio) {
     test.compute_sum();
     test.compute_geometry();
     res = test.edgelength;
-    IF_KEY_EXISTS(it, extra_params, "distunit")
+    if (auto *it = hr::find_or_null(extra_params, "distunit"))
       res /= it->second;
     }
   #endif
   else if(eat("regangle(")) {
     cld edgelen = parse(0);
-    IF_KEY_EXISTS(it, extra_params, "distunit") {
+    if (auto *it = hr::find_or_null(extra_params, "distunit")) {
       edgelen = edgelen * it->second;
       }
     
@@ -260,13 +260,13 @@ cld exp_parser::parse(int prio) {
     
     if(arb::legacy) {
       res = M_PI - result;
-      IF_KEY_EXISTS(it, extra_params, "angleofs")
+      if (auto *it = hr::find_or_null(extra_params, "angleofs"))
         res -= it->second;
       }
     else
       res = result;
 
-    IF_KEY_EXISTS(it, extra_params, "angleunit")
+    if (auto *it = hr::find_or_null(extra_params, "angleunit"))
       res /= it->second;
     }
   else if(eat("test(")) {
@@ -318,8 +318,8 @@ cld exp_parser::parse(int prio) {
   else if(next() == '(') at++, res = parsepar(); 
   else {
     string number = next_token();
-    IF_KEY_EXISTS(it, extra_params, number) res = it->second;
-    else IF_KEY_EXISTS(it, params, number) res = it->second->get_cld();
+    if (auto *it = hr::find_or_null(extra_params, number)) res = it->second;
+    else if (auto *it = hr::find_or_null(params, number)) res = it->second->get_cld();
     else if(number == "e") res = exp(1);
     else if(number == "i") res = cld(0, 1);
     else if(number == "p" || number == "pi") res = M_PI;