1 files changed, 35 insertions, 0 deletions
diff --git a/docs/history/13-gap-fixes/code/examples/lists.zc b/docs/history/13-gap-fixes/code/examples/lists.zc
new file mode 100644
index 0000000..6ac276e
--- /dev/null
+++ b/docs/history/13-gap-fixes/code/examples/lists.zc
@@ -0,0 +1,35 @@
+// ownership in practice: a list owns its boxes. nothing here calls free;
+// everything is released at the end of the block that owns it.
+fn box(v) -> .u { let b = new(1); b[0] = v; return u*b; }
+fn mklist(cap) -> .u { let l = new(cap + 1); l[0] = 0; return u*l; }
+// item m*arrives (it was given down), and goes d*on into the borrowed list
+fn push(.m l, .d item) { l[l[0] + 1] = d*item; l[0] = l[0] + 1; return 0; }
+fn show(.m l)
+{
+	let i = 1;
+	putc('[');
+	while (i <= l[0]) { if (i > 1) putc(' '); putn(l[i][0]); i++; }
+	putc(']');
+	return 0;
+}
+fn squares(n) -> .u
+{
+	let l = mklist(n), i = 0;
+	while (i < n) {
+		let b = box(i * i);
+		push(l, d*b);
+		i++;
+	}
+	return u*l;
+}
+fn main()
+{
+	let before = live_objects();
+	{
+		let l = squares(6);
+		show(l); putc(10);
+		puts("live: "); putn(live_objects() - before); putc(10);
+	}
+	puts("after the block: "); putn(live_objects() - before); putc(10);
+	return 0;
+}