implement enough type analysis for vector example

+ Big commit, scary
+ Some details still a bit up in the air, mainly about move checking
  structure member access ('register' types are freely copied I guess,
  same as in rust? How about user types?)

2 files changed, 53 insertions, 2 deletions

diff --git a/examples/fib.fwd b/examples/fib.fwd
index e6d6ee6..4583a26 100644
--- a/examples/fib.fwd
+++ b/examples/fib.fwd
@@ -25,6 +25,6 @@ fib(i64 n, (i64) res)
 main()
 {
 	fib(42) => i64 n;
-	print_i64(n);
-	print_nl();
+	fwdprint_i64(n);
+	fwdprint_nl();
 }
diff --git a/examples/vec.fwd b/examples/vec.fwd
new file mode 100644
index 0000000..1cc10b3
--- /dev/null
+++ b/examples/vec.fwd
@@ -0,0 +1,51 @@
+import "../mod/libfwdmem.so"
+import "../mod/libfwdutil.so"
+
+/* trait */
+any = {}
+
+/* template */
+vec[any type]() {
+	<> {
+		i64 s;
+		i64 n;
+		*[]type buf;
+	}
+
+	<>create((<>) next)
+	{
+		next((0 => s, 0 => n, * => buf)<>);
+	}
+
+	<>append(<> v, type n, (<>) next)
+	{
+		v.n = v.n + 1;
+		if v.s == 0 {
+			v.s = 1;
+		}
+
+		if v.n > v.s {
+			if v.s == 0 {
+				v.s = 1;
+			}
+
+			v.s = v.s * 2;
+			fwdrealloc(v.buf, v.s as u64 * sizeof(type)) => ptr;
+			v.buf = ptr;
+		}
+
+		/* in a real implementation this would be moved to after
+		 * fwdrealloc I guess, but this is fine for now */
+		nil v.buf {fwdpanic("no buf for vector");} => buf;
+		buf*[v.n - 1] = n;
+		next(v);
+	}
+
+	<>destroy(<> v)
+	{
+		fwdfree(v.buf);
+		nil v;
+	}
+}
+
+u8vec = vec[u8]()