1 files changed, 59 insertions, 0 deletions
diff --git a/misc/examples/hashmaps/vikings.c b/misc/examples/hashmaps/vikings.c
new file mode 100644
index 00000000..cef17a04
--- /dev/null
+++ b/misc/examples/hashmaps/vikings.c
@@ -0,0 +1,59 @@
+#define i_implement
+#include <stc/cstr.h>
+
+typedef struct Viking {
+    cstr name;
+    cstr country;
+} Viking;
+
+void Viking_drop(Viking* vk) {
+    cstr_drop(&vk->name);
+    cstr_drop(&vk->country);
+}
+
+// Define Viking lookup struct with hash, cmp, and convertion functions between Viking and RViking structs:
+
+typedef struct RViking {
+    const char* name;
+    const char* country;
+} RViking;
+
+static inline int RViking_cmp(const RViking* rx, const RViking* ry) {
+    int c = strcmp(rx->name, ry->name);
+    return c ? c : strcmp(rx->country, ry->country);
+}
+
+static inline Viking Viking_from(RViking raw) { // note: parameter is by value
+    return c_LITERAL(Viking){cstr_from(raw.name), cstr_from(raw.country)};
+}
+
+static inline RViking Viking_toraw(const Viking* vp) {
+    return c_LITERAL(RViking){cstr_str(&vp->name), cstr_str(&vp->country)};
+}
+
+// With this in place, we define the Viking => int hash map type:
+#define i_type      Vikings
+#define i_keyclass  Viking      // key type
+#define i_rawclass  RViking     // lookup type
+#define i_keyfrom   Viking_from
+#define i_opt       c_no_clone
+#define i_hash(rp)  stc_strhash(rp->name) ^ stc_strhash(rp->country)
+#define i_val       int         // mapped type
+#include <stc/cmap.h>
+
+int main(void)
+{
+    Vikings vikings = {0};
+    Vikings_emplace(&vikings, c_LITERAL(RViking){"Einar", "Norway"}, 20);
+    Vikings_emplace(&vikings, c_LITERAL(RViking){"Olaf", "Denmark"}, 24);
+    Vikings_emplace(&vikings, c_LITERAL(RViking){"Harald", "Iceland"}, 12);
+    Vikings_emplace(&vikings, c_LITERAL(RViking){"Björn", "Sweden"}, 10);
+
+    Vikings_value* v = Vikings_get_mut(&vikings, c_LITERAL(RViking){"Einar", "Norway"});
+    v->second += 3; // add 3 hp points to Einar
+
+    c_forpair (vk, hp, Vikings, vikings) {
+        printf("%s of %s has %d hp\n", cstr_str(&_.vk->name), cstr_str(&_.vk->country), *_.hp);
+    }
+    Vikings_drop(&vikings);
+}