add hashmap example

+ Doesn't quite work yet because <type> expansion isn't implemented
  yet

1 files changed, 62 insertions, 0 deletions

diff --git a/example_hashmap/new/main.c b/example_hashmap/new/main.c
new file mode 100644
index 0000000..4846ab5
--- /dev/null
+++ b/example_hashmap/new/main.c
@@ -0,0 +1,62 @@
+#include <assert.h>
+#include <stdio.h>
+
+#include "map.h"
+
+#define foreach(name, i, s) \
+	for (name##_iter i = name##_begin(s); !name##_end(s, i); i = name##_next(i))
+
+/* int wrapper, provides cmp/hash for a generic integer type
+ * (here a trait like is_integer would be ideal but oh well) */
+typedef intw[any I]() {
+	typedef I <>;
+
+	size_t <>_hash(<> *a)
+	{
+		/* identity hash */
+		return *a;
+	}
+
+	int <>_cmp(<> *a, <> *b)
+	{
+		return *a - *b;
+	}
+};
+
+/* create wrapper for ints. */
+typedef intw = intw[int]();
+
+/* create hashmap of ints, using the intw wrapper we just created. Kind of
+ * boilerplatey, admittedly. */
+typedef ints = map[intw, intw]();
+
+int main()
+{
+	/* heuristic, but if we know how many elements we'll need, we should
+	 * give it to the create function. */
+	ints ints = ints_create(0);
+	for (int i = 0; i < 1000000; ++i) {
+		ints_insert(&ints, i, i);
+	}
+	assert(ints_len(&ints) == 1000000);
+
+	for (int i = 0; i < 1000000; ++i) {
+		int *v = ints_find(&ints, i);
+		assert(v && *v == i);
+	}
+
+	size_t count = 0;
+	foreach(ints, iter, &ints) {
+		assert(iter->key == iter->data);
+		count++;
+	}
+
+	assert(count == 1000000);
+
+	for (int i = 0; i < 1000000; ++i) {
+		ints_remove(&ints, i);
+	}
+
+	assert(ints_len(&ints) == 0);
+	ints_destroy(&ints);
+}