docs: archive the frozen stage code as one compressed tarball

docs/history kept six stages with a full copy of the project under code/,
3.8 mb of sources duplicated from stage to stage and already superseded. store
them as docs/history/code-snapshots.tar.gz, 0.66 mb, and extract one in place
to read it. every stage's notes.md stays browsable, and the index says where the
code went and how to get it back.

the top-level README points at the archive too. its other two links into
docs/history, 21-micro and 35-bench, were notes that were never kept and do not
resolve; the index now records that.

61 files changed, 0 insertions, 595 deletions

diff --git a/docs/history/15-o3/code/tests/arrays.zc b/docs/history/15-o3/code/tests/arrays.zc
deleted file mode 100644
index f8d46d8..0000000
--- a/docs/history/15-o3/code/tests/arrays.zc
+++ /dev/null
@@ -1,24 +0,0 @@
-// growable arrays and fixed ones
-struct point { int x, y; };
-fn main()
-{
-	let before = live_objects();
-	{
-		[]int a = new([]int);
-		for (int i = 0; i < 100; i++) push(a, i * i);
-		putn(len(a)); putc(' '); putn(cap(a)); putc(' '); putn(a[99]); putc(' ');
-		putn(pop(a)); putc(' '); putn(len(a)); putc(' ');
-		resize(a, 3); putn(len(a)); putc(' '); putn(a[2]); putc(' ');
-		fixed []int f = new(fixed []int, 5);
-		f[4] = 7; putn(f[4] + len(f)); putc(' ');
-		[]point ps = new([]point, 2);
-		ps[1].y = 9; resize(ps, 10); putn(ps[1].y + len(ps)); putc(' ');
-		[8]int st; putn(len(st)); putc(' ');
-		[]*point owned = new([]*point);
-		for (int i = 0; i < 20; i++) { *point p = new(point); p.x = i; push(owned, d*p); }
-		putn(owned[19].x); putc(' ');
-		putn(live_objects() - before); putc(10);
-	}
-	putn(live_objects() - before); putc(10);
-	return 0;
-}
diff --git a/docs/history/15-o3/code/tests/basics.zc b/docs/history/15-o3/code/tests/basics.zc
deleted file mode 100644
index c1f1faf..0000000
--- a/docs/history/15-o3/code/tests/basics.zc
+++ /dev/null
@@ -1,22 +0,0 @@
-let table[10];
-let greeting = "hey";
-const N = 10, BIG = 0x100 * 2;
-fn fib(n) { if (n < 2) return n; return fib(n - 1) + fib(n - 2); }
-fn twice(f, x) { return f(f(x)); }
-fn inc(x) { return x + 1; }
-fn main()
-{
-	let i, s = 0, a[5];
-	for (i = 0; i < N; i++) table[i] = i * i;
-	for (let j = 0; j < N; j++) s += table[j];
-	putn(s); putc(' '); putn(fib(15)); putc(' '); putn(twice(inc, 40)); putc(' '); putn(BIG); putc(10);
-	puts(greeting); putc(' '); putn('A'); putc(' '); putn(-17 / 5); putc(' '); putn(-17 % 5); putc(' '); putn(1 << 10); putc(' '); putn(-64 >> 3); putc(10);
-	i = 0; while (1) { i++; if (i == 3) continue; if (i > 6) break; putn(i); } putc(10);
-	a[0] = 5; a[1] = a[0]++; a[2] = ++a[0]; putn(a[0]); putn(a[1]); putn(a[2]); putc(10);
-	let b = { let t = 3; t * t };
-	putn(b); putc(' '); putn(3 > 2 && 2 > 1); putn(0 || 0); putn(!5); putn(~0); putn(5 != 5); putn(4 >= 4); putc(10);
-	let x = asm { 2 3 + };
-	putn(x); putc(10);
-	asm { 'o' . 'k' . 10 . }
-	return 0;
-}
diff --git a/docs/history/15-o3/code/tests/bench.zc b/docs/history/15-o3/code/tests/bench.zc
deleted file mode 100644
index a7e53f5..0000000
--- a/docs/history/15-o3/code/tests/bench.zc
+++ /dev/null
@@ -1,30 +0,0 @@
-// four kernels with and without o3; bench.sh runs each one on each backend
-int csum(int lim) { int s = 0; for (int n = 1; n < lim; n++) { int x = n; while (x != 1) { if (x & 1) x = 3 * x + 1; else x = x / 2; s++; } } return s; }
-o3 int csum3(int lim) { int s = 0; for (int n = 1; n < lim; n++) { int x = n; while (x != 1) { if (x & 1) x = 3 * x + 1; else x = x / 2; s++; } } return s; }
-int sieve(fixed []int f) { int c = 0, n = len(f); for (int i = 0; i < n; i++) f[i] = 1; for (int i = 2; i < n; i++) if (f[i]) { c++; for (int j = i + i; j < n; j += i) f[j] = 0; } return c; }
-o3 int sieve3(fixed []int f) { int c = 0, n = len(f); for (int i = 0; i < n; i++) f[i] = 1; for (int i = 2; i < n; i++) if (f[i]) { c++; for (int j = i + i; j < n; j += i) f[j] = 0; } return c; }
-int digits(int n) { int s = 0; for (int i = 0; i < n; i++) { int x = i; while (x) { s = s + x % 10; x = x / 10; } } return s; }
-o3 int digits3(int n) { int s = 0; for (int i = 0; i < n; i++) { int x = i; while (x) { s = s + x % 10; x = x / 10; } } return s; }
-int fib(int n) { if (n < 2) return n; return fib(n - 1) + fib(n - 2); }
-o3 int fib3(int n) { if (n < 2) return n; return fib3(n - 1) + fib3(n - 2); }
-// input: a letter (the kernel; z runs none) and how many times to run it
-fn main()
-{
-	fixed []int f = new(fixed []int, 50000);
-	let which = getc(), reps = 0, ch = getc(), r = 0;
-	while (ch >= '0' && ch <= '9') { reps = reps * 10 + ch - '0'; ch = getc(); }
-	while (reps > 0) {
-		if (which == 'a') r = csum(30000);
-		if (which == 'b') r = csum3(30000);
-		if (which == 'c') r = sieve(f);
-		if (which == 'd') r = sieve3(f);
-		if (which == 'e') r = digits(300000);
-		if (which == 'f') r = digits3(300000);
-		if (which == 'g') r = fib(22);
-		if (which == 'h') r = fib3(22);
-		reps--;
-	}
-	putn(r); putc(10);
-	free(d*f);
-	return 0;
-}
diff --git a/docs/history/15-o3/code/tests/borrowmove.zc b/docs/history/15-o3/code/tests/borrowmove.zc
deleted file mode 100644
index 43f27b2..0000000
--- a/docs/history/15-o3/code/tests/borrowmove.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-fn put(.m box, int v) { *int c = new(int); *c = v; box[0] = c; return 0; }
-fn main() { let b = new(1); put(b, 6); putn(*(b[0] as *int)); putc(10); return 0; }
diff --git a/docs/history/15-o3/code/tests/buddy.zc b/docs/history/15-o3/code/tests/buddy.zc
deleted file mode 100644
index 2000598..0000000
--- a/docs/history/15-o3/code/tests/buddy.zc
+++ /dev/null
@@ -1,15 +0,0 @@
-// the buddy allocator: 20000 small blocks, freed, merge back into one big one
-let keep[20000];
-fn main()
-{
-	let i = 0, p;
-	while (i < 20000) { keep[i] = new(2); i++; }   // 20000 8-word blocks
-	putn(largest_free()); putc(' ');
-	i = 0; while (i < 20000) { free(keep[i]); i++; }
-	putn(largest_free()); putc(' ');
-	p = new(200000);	// only possible if the small blocks merged back
-	putn(osize(p) >= 200000); putc(' ');
-	free(d*p);
-	putn(live_objects()); putc(10);
-	return 0;
-}
diff --git a/docs/history/15-o3/code/tests/enhance.zc b/docs/history/15-o3/code/tests/enhance.zc
deleted file mode 100644
index 33eb85b..0000000
--- a/docs/history/15-o3/code/tests/enhance.zc
+++ /dev/null
@@ -1,29 +0,0 @@
-// custom opcodes: recipes, lifted vm code, several outputs, and a fallback
-enhance clampadd(a, b) micro "a = add a b; a = min a 100; a = max a 0";
-enhance cube(x) vm { 0 $ 0 $ * * };
-enhance 2 divmod(a, b) micro "r2 = sdiv a b" "\n r1 = srem a b\n r0 = r2";
-enhance div7(a) micro "a = sdiv a 7";
-enhance urem10(a) micro "a = urem a 10";
-enhance hi(a, b) micro "a = mulhu a b";
-enhance noisy(x) vm { 0 $ . } else soft_noisy;	// i/o can't be lifted, so calls use the fallback
-fn soft_noisy(x) { return x + 1; }
-let qq, rr, seed = 7;
-fn rnd() { seed = seed * 1103515245 + 12345; return seed ^ (seed >> 11); }
-fn main()
-{
-	let i = 0, a, bad = 0;
-	putn(clampadd(70, 50)); putc(' '); putn(clampadd(-50, 2)); putc(' '); putn(cube(7)); putc(' ');
-	asm { 17 5 divmod rr ! qq ! }
-	putn(qq); putc(','); putn(rr); putc(' ');
-	putn(noisy(4)); putc(' ');
-	putn(hi(-1, -1)); putc(' ');
-	while (i < 5000) {
-		a = rnd();
-		if (div7(a) != zdiv(a, 7)) bad++;
-		if (urem10(a) < 0 || urem10(a) > 9) bad++;
-		if (a / (i + 1) != zdiv(a, i + 1)) bad++;
-		i++;
-	}
-	putn(bad); putc(10);
-	return 0;
-}
diff --git a/docs/history/15-o3/code/tests/errors/back_to_m.zc b/docs/history/15-o3/code/tests/errors/back_to_m.zc
deleted file mode 100644
index b8c160f..0000000
--- a/docs/history/15-o3/code/tests/errors/back_to_m.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: x: can't be recast back to m
-fn main() { let x = new(3); d*x; m*x; return 0; }
diff --git a/docs/history/15-o3/code/tests/errors/borrow_escape.zc b/docs/history/15-o3/code/tests/errors/borrow_escape.zc
deleted file mode 100644
index ce24480..0000000
--- a/docs/history/15-o3/code/tests/errors/borrow_escape.zc
+++ /dev/null
@@ -1,3 +0,0 @@
-// expect: p: is owned and can't be returned
-fn f(.m p) { return p; }
-fn main() { let x = new(1); f(x); return 0; }
diff --git a/docs/history/15-o3/code/tests/errors/branch_mismatch.zc b/docs/history/15-o3/code/tests/errors/branch_mismatch.zc
deleted file mode 100644
index bd19968..0000000
--- a/docs/history/15-o3/code/tests/errors/branch_mismatch.zc
+++ /dev/null
@@ -1,3 +0,0 @@
-// expect: x: ends the branches of an if in different states
-fn take(.d p) { return p[0]; }
-fn main() { let x = new(1); if (x[0]) take(d*x); else u*x; return 0; }
diff --git a/docs/history/15-o3/code/tests/errors/child_dies.zc b/docs/history/15-o3/code/tests/errors/child_dies.zc
deleted file mode 100644
index 67caca9..0000000
--- a/docs/history/15-o3/code/tests/errors/child_dies.zc
+++ /dev/null
@@ -1,3 +0,0 @@
-// expect: c: used after it was given away
-fn take(.d p) { return p[0]; }
-fn main() { let p = new(2), c = new(1); p[0] = c; take(d*p); return c[0]; }
diff --git a/docs/history/15-o3/code/tests/errors/child_recast.zc b/docs/history/15-o3/code/tests/errors/child_recast.zc
deleted file mode 100644
index c9ccd62..0000000
--- a/docs/history/15-o3/code/tests/errors/child_recast.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: c: belongs to a container; recast the container instead
-fn main() { let p = new(2), c = new(1); p[0] = c; d*c; return 0; }
diff --git a/docs/history/15-o3/code/tests/errors/copy_owned.zc b/docs/history/15-o3/code/tests/errors/copy_owned.zc
deleted file mode 100644
index 862c7ef..0000000
--- a/docs/history/15-o3/code/tests/errors/copy_owned.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: x: is an owned object and can't be copied
-fn main() { let x = new(1); let y = x; return y[0]; }
diff --git a/docs/history/15-o3/code/tests/errors/d_into_block.zc b/docs/history/15-o3/code/tests/errors/d_into_block.zc
deleted file mode 100644
index 2d7f526..0000000
--- a/docs/history/15-o3/code/tests/errors/d_into_block.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: x: used after it was given away
-fn main() { let x = new(1); d*x; { x[0] = 5; } return x[0]; }
diff --git a/docs/history/15-o3/code/tests/errors/d_kept.zc b/docs/history/15-o3/code/tests/errors/d_kept.zc
deleted file mode 100644
index dcbfb86..0000000
--- a/docs/history/15-o3/code/tests/errors/d_kept.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: x: d object was never given away
-fn main() { let x = new(3); d*x; x[0] = 1; return 0; }
diff --git a/docs/history/15-o3/code/tests/errors/discard_u.zc b/docs/history/15-o3/code/tests/errors/discard_u.zc
deleted file mode 100644
index 9293378..0000000
--- a/docs/history/15-o3/code/tests/errors/discard_u.zc
+++ /dev/null
@@ -1,3 +0,0 @@
-// expect: can't be thrown away
-.u mk() { let p = new(1); return u*p; }
-fn main() { mk(); return 0; }
diff --git a/docs/history/15-o3/code/tests/errors/give_m.zc b/docs/history/15-o3/code/tests/errors/give_m.zc
deleted file mode 100644
index cd67896..0000000
--- a/docs/history/15-o3/code/tests/errors/give_m.zc
+++ /dev/null
@@ -1,3 +0,0 @@
-// expect: x: is m; write d*x
-fn take(.d p) { return p[0]; }
-fn main() { let x = new(3); take(x); return 0; }
diff --git a/docs/history/15-o3/code/tests/errors/global_store.zc b/docs/history/15-o3/code/tests/errors/global_store.zc
deleted file mode 100644
index dc0e546..0000000
--- a/docs/history/15-o3/code/tests/errors/global_store.zc
+++ /dev/null
@@ -1,3 +0,0 @@
-// expect: x: must be d to be stored in a global
-let g;
-fn main() { let x = new(1); g = x; return 0; }
diff --git a/docs/history/15-o3/code/tests/errors/leak_overwrite.zc b/docs/history/15-o3/code/tests/errors/leak_overwrite.zc
deleted file mode 100644
index d19b5fd..0000000
--- a/docs/history/15-o3/code/tests/errors/leak_overwrite.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: x: still owns an object
-fn main() { let x = new(1); x = new(2); return x[0]; }
diff --git a/docs/history/15-o3/code/tests/errors/lend_d.zc b/docs/history/15-o3/code/tests/errors/lend_d.zc
deleted file mode 100644
index 55ac7e0..0000000
--- a/docs/history/15-o3/code/tests/errors/lend_d.zc
+++ /dev/null
@@ -1,4 +0,0 @@
-// expect: x: is d; pass it to a d parameter
-fn look(.m p) { return p[0]; }
-fn take(.d p) { return p[0]; }
-fn main() { let x = new(3); d*x; look(x); take(x); return 0; }
diff --git a/docs/history/15-o3/code/tests/errors/loop_move.zc b/docs/history/15-o3/code/tests/errors/loop_move.zc
deleted file mode 100644
index df3c94a..0000000
--- a/docs/history/15-o3/code/tests/errors/loop_move.zc
+++ /dev/null
@@ -1,3 +0,0 @@
-// expect: x: is given away inside a loop that comes back around to it
-fn take(.d p) { return p[0]; }
-fn main() { let x = new(1); let i = 0; d*x; while (i < 3) { take(x); i++; } return 0; }
diff --git a/docs/history/15-o3/code/tests/errors/plain_return.zc b/docs/history/15-o3/code/tests/errors/plain_return.zc
deleted file mode 100644
index 45fb545..0000000
--- a/docs/history/15-o3/code/tests/errors/plain_return.zc
+++ /dev/null
@@ -1,3 +0,0 @@
-// expect: returns a new object; give the function a .u return type
-fn mk() { return new(1); }
-fn main() { return mk(); }
diff --git a/docs/history/15-o3/code/tests/errors/return_m.zc b/docs/history/15-o3/code/tests/errors/return_m.zc
deleted file mode 100644
index b5ef519..0000000
--- a/docs/history/15-o3/code/tests/errors/return_m.zc
+++ /dev/null
@@ -1,3 +0,0 @@
-// expect: x: has to be u to be returned
-.u mk() { let x = new(1); return x; }
-fn main() { let y = mk(); return y[0]; }
diff --git a/docs/history/15-o3/code/tests/errors/tag_mismatch.zc b/docs/history/15-o3/code/tests/errors/tag_mismatch.zc
deleted file mode 100644
index 079f249..0000000
--- a/docs/history/15-o3/code/tests/errors/tag_mismatch.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: c: its tag doesn't match its container's
-fn main() { let p = new(2), c = new(1); u*p; p[0] = c; return 0; }
diff --git a/docs/history/15-o3/code/tests/errors/u_dropped.zc b/docs/history/15-o3/code/tests/errors/u_dropped.zc
deleted file mode 100644
index e1ca68a..0000000
--- a/docs/history/15-o3/code/tests/errors/u_dropped.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: x: u object must leave this block
-fn main() { let x = new(3); u*x; return 0; }
diff --git a/docs/history/15-o3/code/tests/errors/u_skip_level.zc b/docs/history/15-o3/code/tests/errors/u_skip_level.zc
deleted file mode 100644
index 6caeeb3..0000000
--- a/docs/history/15-o3/code/tests/errors/u_skip_level.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: t: is u; it can only be handed to a variable of the enclosing block
-fn main() { let r; { { let t = new(1); u*t; r = t; } } return r[0]; }
diff --git a/docs/history/15-o3/code/tests/errors/unchecked_touch.zc b/docs/history/15-o3/code/tests/errors/unchecked_touch.zc
deleted file mode 100644
index 141639d..0000000
--- a/docs/history/15-o3/code/tests/errors/unchecked_touch.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: x: is tracked by the analyzer and can't be used in unchecked code
-fn main() { let x = new(1); unchecked { x[0] = 1; } return 0; }
diff --git a/docs/history/15-o3/code/tests/errors/unused.zc b/docs/history/15-o3/code/tests/errors/unused.zc
deleted file mode 100644
index 64aff1f..0000000
--- a/docs/history/15-o3/code/tests/errors/unused.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: x: m object is never used
-fn main() { let x = new(3); return 0; }
diff --git a/docs/history/15-o3/code/tests/errors/use_after_give.zc b/docs/history/15-o3/code/tests/errors/use_after_give.zc
deleted file mode 100644
index 8a10922..0000000
--- a/docs/history/15-o3/code/tests/errors/use_after_give.zc
+++ /dev/null
@@ -1,3 +0,0 @@
-// expect: x: used after it was given away
-fn take(.d p) { return p[0]; }
-fn main() { let x = new(3); take(d*x); return x[0]; }
diff --git a/docs/history/15-o3/code/tests/gc.zc b/docs/history/15-o3/code/tests/gc.zc
deleted file mode 100644
index 41f14a0..0000000
--- a/docs/history/15-o3/code/tests/gc.zc
+++ /dev/null
@@ -1,20 +0,0 @@
-let keep;
-unchecked fn churn(n)
-{
-	let i = 0, p;
-	while (i < n) { p = new(10); p[0] = i; if (i % 100 == 0) keep = p; i++; }
-	return 0;
-}
-fn main()
-{
-	let base = live_objects(), f;
-	churn(1000);
-	putn(live_objects() - base); putc(' ');
-	f = gc();
-	putn(f >= 990); putc(' ');		// conservative: a stale word or two may keep one alive
-	putn(keep[0]); putc(' ');		// the one a global still points at survives
-	churn(200000);				// 3.2m words through a 393k word heap: needs the automatic collector
-	putn(gc_runs > 1); putc(' ');
-	putn(keep[0]); putc(10);
-	return 0;
-}
diff --git a/docs/history/15-o3/code/tests/joins.zc b/docs/history/15-o3/code/tests/joins.zc
deleted file mode 100644
index 913929b..0000000
--- a/docs/history/15-o3/code/tests/joins.zc
+++ /dev/null
@@ -1,32 +0,0 @@
-// joins: something given away on one path is dead afterwards, and the paths
-// that still own it free it on the way in. nothing here leaks.
-fn take(.d p) { return p[0]; }
-fn later(.d p);	// not needed any more, but still allowed
-*int.u mk(int v) { *int p = new(int); *p = v; return u*p; }
-fn count(int n) { let s = 0; switch (n % 4) { case 0: s = 10; case 1, 2: s = 20; break; default: s = 30; } return s; }
-fn main()
-{
-	let base = live_objects(), i = 0, hits = 0, k;
-	while (i < 50) {
-		let x = mk(i);
-		if (i % 3 == 0) take(d*x);	// else: freed here by the fixup
-		i++;
-	}
-	putn(live_objects() - base); putc(' ');
-	// give away and break: fine now; the normal exit frees it
-	i = 0;
-	let y = mk(7);
-	while (i < 10) { if (i == 4) { take(d*y); break; } i++; }
-	putn(live_objects() - base); putc(' ');
-	let z = mk(5);
-	while (1) { if (z[0] == 5) { hits = take(d*z); break; } }
-	putn(hits); putc(' ');
-	putn(count(0) + count(1) + count(2) + count(3)); putc(' ');
-	k = i > 3 ? i * 2 : 0 - 1;
-	putn(k); putc(' ');
-	putn(forward(new(int))); putc(' ');	// tagged and defined below: the prescan knows .d
-	**int pp; *int q = new(int); *q = 9; pp = &q; putn(**pp); free(d*q); putc(' ');
-	putn(live_objects() - base); putc(10);
-	return 0;
-}
-fn forward(*int.d p) { return 3 + *p; }
diff --git a/docs/history/15-o3/code/tests/langerrors/const_index.zc b/docs/history/15-o3/code/tests/langerrors/const_index.zc
deleted file mode 100644
index 03e927b..0000000
--- a/docs/history/15-o3/code/tests/langerrors/const_index.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: the index is out of range for this array
-fn main() { [4]int a; a[4] = 1; return 0; }
diff --git a/docs/history/15-o3/code/tests/langerrors/fixed_nolen.zc b/docs/history/15-o3/code/tests/langerrors/fixed_nolen.zc
deleted file mode 100644
index b79c31e..0000000
--- a/docs/history/15-o3/code/tests/langerrors/fixed_nolen.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: a fixed array needs its length
-fn main() { fixed []int f = new(fixed []int); free(d*f); return 0; }
diff --git a/docs/history/15-o3/code/tests/langerrors/fixed_push.zc b/docs/history/15-o3/code/tests/langerrors/fixed_push.zc
deleted file mode 100644
index a19bcb4..0000000
--- a/docs/history/15-o3/code/tests/langerrors/fixed_push.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: a fixed array can't grow or shrink
-fn main() { fixed []int f = new(fixed []int, 3); push(f, 1); free(d*f); return 0; }
diff --git a/docs/history/15-o3/code/tests/langerrors/fixed_to_dyn.zc b/docs/history/15-o3/code/tests/langerrors/fixed_to_dyn.zc
deleted file mode 100644
index 483f62f..0000000
--- a/docs/history/15-o3/code/tests/langerrors/fixed_to_dyn.zc
+++ /dev/null
@@ -1,4 +0,0 @@
-// expect: type error: argument: expected []int, got fixed []int
-typecheck on;
-int take([]int.m g) { return len(g); }
-fn main() { fixed []int f = new(fixed []int, 3); take(f); free(d*f); return 0; }
diff --git a/docs/history/15-o3/code/tests/langerrors/o3_addr.zc b/docs/history/15-o3/code/tests/langerrors/o3_addr.zc
deleted file mode 100644
index 815253d..0000000
--- a/docs/history/15-o3/code/tests/langerrors/o3_addr.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: an o3 variable has no address
-fn main() { o3 int z = 2; *int q = &z; return *q; }
diff --git a/docs/history/15-o3/code/tests/langerrors/o3_asm.zc b/docs/history/15-o3/code/tests/langerrors/o3_asm.zc
deleted file mode 100644
index c8afb44..0000000
--- a/docs/history/15-o3/code/tests/langerrors/o3_asm.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: asm can't reach an o3 variable
-fn main() { o3 int zz = 2; asm { zz @ _ } return 0; }
diff --git a/docs/history/15-o3/code/tests/langerrors/o3_let.zc b/docs/history/15-o3/code/tests/langerrors/o3_let.zc
deleted file mode 100644
index d2aff9a..0000000
--- a/docs/history/15-o3/code/tests/langerrors/o3_let.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: o3 variables need a type
-fn main() { o3 { let x = 1; x++; } return 0; }
diff --git a/docs/history/15-o3/code/tests/langerrors/o3_param.zc b/docs/history/15-o3/code/tests/langerrors/o3_param.zc
deleted file mode 100644
index 5694720..0000000
--- a/docs/history/15-o3/code/tests/langerrors/o3_param.zc
+++ /dev/null
@@ -1,3 +0,0 @@
-// expect: o3 parameters need a type
-o3 int f(x) { return x; }
-fn main() { return f(1); }
diff --git a/docs/history/15-o3/code/tests/manyerrors.zc b/docs/history/15-o3/code/tests/manyerrors.zc
deleted file mode 100644
index f4c0c68..0000000
--- a/docs/history/15-o3/code/tests/manyerrors.zc
+++ /dev/null
@@ -1,6 +0,0 @@
-// several errors in one run: a syntax error, an analyzer error, a type error
-typecheck on;
-fn f() { let a = ; return 0; }
-fn g() { let x = new(3); return 0; }
-int h() { *char s = 5; return 1; }
-fn main() { return 0 }
diff --git a/docs/history/15-o3/code/tests/meta.zc b/docs/history/15-o3/code/tests/meta.zc
deleted file mode 100644
index bc89454..0000000
--- a/docs/history/15-o3/code/tests/meta.zc
+++ /dev/null
@@ -1,46 +0,0 @@
-fn ipow(a, b) { let r = 1; while (b > 0) { r *= a; b--; } return r; }
-// a parse word that adds an operator to the compiler's tables
-immediate fn pow_op() { next(); add_binop("**", 11, "ipow c"); return 0; }
-pow_op
-
-// unless (cond) stmt: a parse word that emits code itself
-immediate fn unless()
-{
-	let a;
-	next();
-	expect(intern("(")); rval(); plainuse(expr()); rval(); expect(intern(")"));
-	emitseq(useq[0], ulen[0]);	// not
-	a = hole(); op(O_JZ);		// skip the body when the condition was true
-	substmt();
-	setlit(a, here);
-	return 0;
-}
-// repeat N { body }: a macro, built from token lists
-immediate fn repeat()
-{
-	let n, body, i = 0;
-	next(); n = tv; next();
-	body = grab();
-	while (i < n) { feed(qdup(body)); i++; }
-	free(d*body);
-	return 0;
-}
-fn main()
-{
-	putn(2 ** 10); putc(' '); putn(3 + 2 ** 3 * 2); putc(10);
-	unless (1 > 2) puts("unless ok\n");
-	unless (2 > 1) puts("wrong\n");
-	repeat 3 { putc('r'); }
-	putc(10);
-	let q = quote { putn(40 + 2); putc(10); return 7; };
-	putn(q[0]); putc(' ');
-	putn(eval(q)); putc(10);
-	let f = compile(q);
-	putn(f()); putc(10);
-	free(d*q);
-	let defs = quote { fn sq(x) { return x * x; } };
-	load(defs);
-	free(d*defs);
-	putn(evals("return sq(12);")); putc(10);
-	return 0;
-}
diff --git a/docs/history/15-o3/code/tests/misc.zc b/docs/history/15-o3/code/tests/misc.zc
deleted file mode 100644
index 25fc53b..0000000
--- a/docs/history/15-o3/code/tests/misc.zc
+++ /dev/null
@@ -1,30 +0,0 @@
-// ct { ... } runs a block while compiling and leaves its result as a constant
-immediate fn ct()
-{
-	let q, v;
-	next();
-	q = grab();
-	v = eval(q);
-	free(d*q);
-	lit(v);
-	return 0;
-}
-// teach the asm syntax that p means out, like the old repl demo
-immediate fn teach() { next(); mnem[12] = 'p'; return 0; }
-teach
-
-fn countdown()
-{
-	asm { 5 :top 0 $ '0' + p 1 - 0 $ done z top j :done _ 10 p }
-	return 0;
-}
-fn main()
-{
-	putn(ct { let i = 0, s = 0; while (i < 10) { s += i; i++; } return s; }); putc(10);
-	countdown();
-	puts(lazy()); putc(10);
-	return 0;
-}
-// the analyzer is off from here on
-unchecked;
-fn lazy() { let p = new(3); p[0] = 'o'; p[1] = 'k'; return p; }
diff --git a/docs/history/15-o3/code/tests/o3.zc b/docs/history/15-o3/code/tests/o3.zc
deleted file mode 100644
index 296d1d5..0000000
--- a/docs/history/15-o3/code/tests/o3.zc
+++ /dev/null
@@ -1,83 +0,0 @@
-// o3 regions: every kind of control flow, against the same code without o3
-struct pt { int x; int y; };
-int g = 3;
-int sq(int x) { return x * x; }
-o3 int collatz(int n)
-{
-	int steps = 0;
-	while (n != 1) { if (n % 2 == 0) n = n / 2; else n = 3 * n + 1; steps++; }
-	return steps;
-}
-o3 int ack(int am, int n)
-{
-	if (am == 0) return n + 1;
-	if (n == 0) return ack(am - 1, 1);
-	return ack(am - 1, ack(am, n - 1));
-}
-o3 int many(int a, int b, int c)
-{
-	int dd = a + b, e = b + c, f = c + a, h = dd * e, i2 = e * f, j = f * dd, k = h + i2 + j, l = k / 7;
-	for (int t = 0; t < 5; t++) { dd += t; e -= t; f = f ^ t; l = l + dd * e - f; }
-	return dd + e + f + h + i2 + j + k + l;
-}
-o3 int mix(int n)
-{
-	int acc = 0;
-	for (int i = 0; i < n; i++) {
-		if (i % 3 == 0 && i % 5 == 0) acc += 15;
-		else if (i % 3 == 0 || i > 90) acc += 3;
-		else acc = acc + (i & 1 ? sq(i) : g);
-		switch (i % 4) { case 0: acc += 1; case 1: acc -= 2; default: acc = acc ^ 1; }
-		if (acc > 100000) break;
-		if (i == 7) continue;
-		acc = acc + i / 10 - i % 7 + (i << 2) - (i >> 1);
-	}
-	return acc;
-}
-o3 int dyn(int n)
-{
-	[]int a = new([]int, n);
-	fixed []int f = new(fixed []int, n);
-	int s = 0;
-	for (int i = 0; i < len(a); i++) { a[i] = i * i; f[i] = n - i; }
-	for (int i = 0; i < n; i++) s = s + a[i] * f[i];
-	free(d*a); free(d*f);
-	return s;
-}
-o3 int pts(int n)
-{
-	*pt p = new(pt);
-	int s = 0;
-	p->x = 1; p->y = 2;
-	for (int i = 0; i < n; i++) { p->x = p->x + p->y; p->y = p->x - p->y; s = s + p->x % 1000; }
-	free(d*p);
-	return s;
-}
-o3 int divs(int x)
-{
-	int s = 0;
-	for (int i = -50; i < 50; i++) s = s + (x + i) / 7 + (x + i) % 7 + (x - i) / -3 + i / 16 + i % 16;
-	return s;
-}
-fn main()
-{
-	o3 int lone = 2;
-	let r = 0;
-	lone = lone * 21;
-	o3 {
-		int i = 0, s = 0;
-		while (i < 100) { s = s + collatz(i + 1); i++; }
-		putn(s); putc(' ');
-		putn(lone); putc(' ');
-		lone++;
-	}
-	putn(lone); putc(' ');
-	putn(ack(2, 3)); putc(' ');
-	putn(many(1, 2, 3)); putc(' ');
-	putn(mix(100)); putc(' ');
-	putn(dyn(50)); putc(' ');
-	putn(pts(30)); putc(' ');
-	putn(divs(1000)); putc(' ');
-	putn(divs(-77)); putc(10);
-	return 0;
-}
diff --git a/docs/history/15-o3/code/tests/o3_bounds.zc b/docs/history/15-o3/code/tests/o3_bounds.zc
deleted file mode 100644
index fb347c0..0000000
--- a/docs/history/15-o3/code/tests/o3_bounds.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// an index outside a []T inside o3 code: caught by the inline check
-fn main() { []int a = new([]int, 5); o3 { int i = 7; a[i] = 1; } free(d*a); return 0; }
diff --git a/docs/history/15-o3/code/tests/overflow_data.zc b/docs/history/15-o3/code/tests/overflow_data.zc
deleted file mode 100644
index 3042f0a..0000000
--- a/docs/history/15-o3/code/tests/overflow_data.zc
+++ /dev/null
@@ -1 +0,0 @@
-fn main() { while (1) asm { 1 } return 0; }
diff --git a/docs/history/15-o3/code/tests/overflow_frame.zc b/docs/history/15-o3/code/tests/overflow_frame.zc
deleted file mode 100644
index 3897bf4..0000000
--- a/docs/history/15-o3/code/tests/overflow_frame.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-fn big(n) { let a[500]; a[0] = n; return big(n + 1) + a[0]; }
-fn main() { return big(0); }
diff --git a/docs/history/15-o3/code/tests/overflow_return.zc b/docs/history/15-o3/code/tests/overflow_return.zc
deleted file mode 100644
index 9d5c622..0000000
--- a/docs/history/15-o3/code/tests/overflow_return.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-fn deep(n) { return deep(n + 1) + 1; }
-fn main() { return deep(0); }
diff --git a/docs/history/15-o3/code/tests/runerr.sh b/docs/history/15-o3/code/tests/runerr.sh
deleted file mode 100755
index 23ea054..0000000
--- a/docs/history/15-o3/code/tests/runerr.sh
+++ /dev/null
@@ -1,10 +0,0 @@
-#!/bin/bash
-# runs every .zc in a folder (tests/errors by default) and checks the compiler
-# rejects it with the message on its first line: // expect: ...
-vm=${1:-zy}; dir=${2:-$(dirname "$0")/errors}; pass=0; fail=0
-for f in "$dir"/*.zc; do
-	want=$(head -1 "$f" | sed 's#^// expect: ##')
-	got=$($vm < "$f" 2>&1 | head -1)
-	if [[ "$got" == *"$want"* ]]; then pass=$((pass+1)); else fail=$((fail+1)); echo "FAIL $(basename $f): got [$got]"; fi
-done
-echo "rejected: $pass passed, $fail failed"
diff --git a/docs/history/15-o3/code/tests/typeerrors/arg.zc b/docs/history/15-o3/code/tests/typeerrors/arg.zc
deleted file mode 100644
index 909672a..0000000
--- a/docs/history/15-o3/code/tests/typeerrors/arg.zc
+++ /dev/null
@@ -1,5 +0,0 @@
-// expect: type error: argument: expected *point, got *int
-typecheck on;
-struct point { int x, y; };
-int f(*point p) { return p.x; }
-fn main() { *int q = new(int); f(q); free(d*q); return 0; }
diff --git a/docs/history/15-o3/code/tests/typeerrors/arith.zc b/docs/history/15-o3/code/tests/typeerrors/arith.zc
deleted file mode 100644
index 76e3111..0000000
--- a/docs/history/15-o3/code/tests/typeerrors/arith.zc
+++ /dev/null
@@ -1,3 +0,0 @@
-// expect: type error: arithmetic needs numbers, got *int
-typecheck on;
-fn main() { *int p = 0; int x = p * 2; return x; }
diff --git a/docs/history/15-o3/code/tests/typeerrors/assign.zc b/docs/history/15-o3/code/tests/typeerrors/assign.zc
deleted file mode 100644
index 8b8a888..0000000
--- a/docs/history/15-o3/code/tests/typeerrors/assign.zc
+++ /dev/null
@@ -1,3 +0,0 @@
-// expect: type error: initializer: expected *char, got int
-typecheck on;
-fn main() { *char s = 5; return 0; }
diff --git a/docs/history/15-o3/code/tests/typeerrors/call.zc b/docs/history/15-o3/code/tests/typeerrors/call.zc
deleted file mode 100644
index 7b03dbf..0000000
--- a/docs/history/15-o3/code/tests/typeerrors/call.zc
+++ /dev/null
@@ -1,3 +0,0 @@
-// expect: type error: only functions can be called, got int
-typecheck on;
-fn main() { int k = 3; return k(1); }
diff --git a/docs/history/15-o3/code/tests/typeerrors/deref.zc b/docs/history/15-o3/code/tests/typeerrors/deref.zc
deleted file mode 100644
index ed030f5..0000000
--- a/docs/history/15-o3/code/tests/typeerrors/deref.zc
+++ /dev/null
@@ -1,3 +0,0 @@
-// expect: type error: only pointers can be dereferenced, got int
-typecheck on;
-fn main() { int x = 3; return *x; }
diff --git a/docs/history/15-o3/code/tests/typeerrors/field.zc b/docs/history/15-o3/code/tests/typeerrors/field.zc
deleted file mode 100644
index ba03697..0000000
--- a/docs/history/15-o3/code/tests/typeerrors/field.zc
+++ /dev/null
@@ -1,3 +0,0 @@
-// expect: point has no field z
-struct point { int x, y; };
-fn main() { point p; return p.z; }
diff --git a/docs/history/15-o3/code/tests/typeerrors/generic.zc b/docs/history/15-o3/code/tests/typeerrors/generic.zc
deleted file mode 100644
index 6d4c4da..0000000
--- a/docs/history/15-o3/code/tests/typeerrors/generic.zc
+++ /dev/null
@@ -1,4 +0,0 @@
-// expect: type error: argument: expected int, got *char
-typecheck on;
-<T> T same(T a, T b) { return a; }
-fn main() { return same(1, "x"); }
diff --git a/docs/history/15-o3/code/tests/typeerrors/notstruct.zc b/docs/history/15-o3/code/tests/typeerrors/notstruct.zc
deleted file mode 100644
index 0dff6bd..0000000
--- a/docs/history/15-o3/code/tests/typeerrors/notstruct.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// expect: .x: that's a int, not a struct or a pointer to one
-fn main() { int n = 1; return n.x; }
diff --git a/docs/history/15-o3/code/tests/typeerrors/ret.zc b/docs/history/15-o3/code/tests/typeerrors/ret.zc
deleted file mode 100644
index be951d5..0000000
--- a/docs/history/15-o3/code/tests/typeerrors/ret.zc
+++ /dev/null
@@ -1,4 +0,0 @@
-// expect: type error: return value: expected bool, got *char
-typecheck on;
-bool f() { return "no"; }
-fn main() { return f(); }
diff --git a/docs/history/15-o3/code/tests/typeerrors/voidret.zc b/docs/history/15-o3/code/tests/typeerrors/voidret.zc
deleted file mode 100644
index 86c9c17..0000000
--- a/docs/history/15-o3/code/tests/typeerrors/voidret.zc
+++ /dev/null
@@ -1,4 +0,0 @@
-// expect: type error: return value: expected void, got int
-typecheck on;
-void f() { return 3; }
-fn main() { f(); return 0; }
diff --git a/docs/history/15-o3/code/tests/typeoff.zc b/docs/history/15-o3/code/tests/typeoff.zc
deleted file mode 100644
index e44e450..0000000
--- a/docs/history/15-o3/code/tests/typeoff.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// the typechecker is off unless asked for: this mismatch compiles and runs
-fn main() { *char s = 5; putn(s as int + 1); putc(10); return 0; }
diff --git a/docs/history/15-o3/code/tests/typeok.zc b/docs/history/15-o3/code/tests/typeok.zc
deleted file mode 100644
index 2d1997b..0000000
--- a/docs/history/15-o3/code/tests/typeok.zc
+++ /dev/null
@@ -1,21 +0,0 @@
-// passes the typechecker: words mix with everything, literal 0 is null,
-// arrays decay to pointers, generic calls bind their parameters
-typecheck on;
-struct pair<A, B> { A a; B b; };
-<A, B> *pair<A, B>.u mk(A x, B y) { *pair<A, B> p = new(pair<A, B>); p.a = x; p.b = y; return u*p; }
-<A, B> A left(*pair<A, B> p) { return p.a; }
-int strlen2(*char s) { int n = 0; while (s[n]) n++; return n; }
-int main() {
-	*pair<int, *char> p = mk(3, "four");
-	int a = left(p);
-	*char s = p.b;
-	[8]char buf;
-	*char q = buf;
-	*int nothing = 0;
-	let w = 5;
-	int mixed = w + 1;
-	q[0] = 'h'; q[1] = 0;
-	putn(a + strlen2(s) + strlen2(buf) + mixed); putc(10);
-	free(d*p);
-	return 0;
-}
diff --git a/docs/history/15-o3/code/tests/types.zc b/docs/history/15-o3/code/tests/types.zc
deleted file mode 100644
index 3408d10..0000000
--- a/docs/history/15-o3/code/tests/types.zc
+++ /dev/null
@@ -1,56 +0,0 @@
-struct point { int x, y; };
-struct rect { point a, b; int tag; };
-struct list<T> { int len; *T items; };
-struct node { int v; *node next; };
-type num = int;
-
-int counter = 5;
-[4]int squares;
-point origin;
-
-int area(*rect r) { return (r.b.x - r.a.x) * (r.b.y - r.a.y); }
-<T> *list<T>.u mklist(int cap) {
-	*list<T> l = new(list<T>);
-	l.len = 0;
-	l.items = new(T, cap) as *T;
-	return u*l;
-}
-<T> T first(*list<T> l) { return l.items[0]; }
-int sum(*node n) { int s = 0; while (n) { s += n.v; n = n.next; } return s; }
-
-fn main()
-{
-	rect r;
-	r.a.x = 1; r.a.y = 2; r.b.x = 4; r.b.y = 6;
-	putn(area(&r)); putc(' ');
-	putn(sizeof(rect)); putc(' '); putn(sizeof(point)); putc(' '); putn(sizeof([3]rect)); putc(' ');
-	let p = new(point);	// let infers *point
-	p.x = 7; p->y = 8;
-	putn(p.x * p.y); putc(' ');
-	free(d*p);
-	*list<int> l = mklist<int>(4);
-	l.items[0] = 42; l.len = 1;
-	putn(first(l)); putc(' ');
-	free(d*l);
-	*node a = new(node), b = new(node);
-	a.v = 3; b.v = 4; a.next = b;
-	putn(sum(a)); putc(' ');
-	free(d*a);	// b went with it: a.next = b made a its owner
-	[3]point pts;
-	pts[2].y = 9;
-	putn(pts[2].y + counter); putc(' ');
-	num k = 3;
-	putn(k); putc(10);
-
-	// reflection
-	tprint(typeof(r)); putc(' '); tprint(typeof(&r)); putc(' '); tprint(typeof(l)); putc(' ');
-	tprint(sigof(mklist)); putc(' '); tprint(sigof(first)); putc(' '); tprint(sigofs("free")); putc(10);
-	let t = typeof(r), i = 0;
-	while (i < tnfields(t)) { puts(tfname(t, i)); putc(':'); tprint(tftype(t, i)); putc('@'); putn(tfoff(t, i)); putc(' '); i++; }
-	putc(10);
-	*point q = new(point);
-	tprint(typeof_obj(q)); putc(' '); putn(typeof_obj(q) == typeof(point)); putc(' '); putn(tkind(typeof_obj(q)) == TY_STRUCT);
-	free(d*q);
-	putc(10);
-	return 0;
-}
diff --git a/docs/history/15-o3/code/tests/umd.zc b/docs/history/15-o3/code/tests/umd.zc
deleted file mode 100644
index 497c9fc..0000000
--- a/docs/history/15-o3/code/tests/umd.zc
+++ /dev/null
@@ -1,51 +0,0 @@
-// lists as [len, items...], items owned by the list
-.u mklist(n) {
-	let l = new(n + 1);
-	l[0] = 0;
-	return u*l;
-}
-fn push(.m l, .d item) { l[l[0] + 1] = d*item; l[0] = l[0] + 1; return 0; }
-fn sum(.m l) { let s = 0, i = 1; while (i <= l[0]) { s += l[i][0]; i++; } return s; }
-.u box(v) { let b = new(1); b[0] = v; return u*b; }
-fn consume(.d b) { return b[0]; }
-
-fn main()
-{
-	let base = live_objects();
-	{
-		let l = mklist(8);		// u from mklist arrives m*here
-		let i = 0;
-		while (i < 5) {
-			let b = box(i * 10);	// m in the loop body
-			d*b;			// give it down
-			push(l, b);
-			i++;
-		}
-		putn(sum(l)); putc(' ');
-		putn(live_objects() - base); putc(' ');	// list + 5 boxes
-	}
-	putn(live_objects() - base); putc(' ');	// freed at the block's end, children too
-
-	// u handed up one block by assignment, and as a block value
-	let outer;
-	{
-		let t = box(7);
-		u*t;
-		outer = t;
-	}
-	let v = { let w = box(8); u*w };
-	putn(outer[0] + v[0]); putc(' ');
-
-	// d given away to a callee
-	let g = box(99);
-	putn(consume(d*g)); putc(' ');
-
-	// containers: child takes its parent's tag
-	let p = new(2), c = new(1);
-	c[0] = 5;
-	p[0] = c;
-	p[1] = new(3);
-	putn(p[0][0]); putc(' ');
-	putn(live_objects() - base); putc(10);
-	return 0;
-}