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3.8 mb of sources duplicated from stage to stage and already superseded.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.

6 files changed, 0 insertions, 86 deletions

diff --git a/docs/history/10-zc/code/examples/echo.zc b/docs/history/10-zc/code/examples/echo.zc
deleted file mode 100644
index 01f28b0..0000000
--- a/docs/history/10-zc/code/examples/echo.zc
+++ /dev/null
@@ -1,2 +0,0 @@
-// everything after the backtick is left unread, for the program itself
-fn main() { while (!eof()) putc(getc()); return 0; }
diff --git a/docs/history/10-zc/code/examples/fact.zc b/docs/history/10-zc/code/examples/fact.zc
deleted file mode 100644
index 2a218b2..0000000
--- a/docs/history/10-zc/code/examples/fact.zc
+++ /dev/null
@@ -1,4 +0,0 @@
-fn fact(n) { if (n < 2) return 1; return n * fact(n - 1); }
-// prints in binary, like the old asm example
-fn bin(n) { if (n > 1) bin(n >> 1); putc('0' + (n & 1)); return 0; }
-fn main() { bin(fact(10)); putc(10); putn(fact(10)); putc(10); return 0; }
diff --git a/docs/history/10-zc/code/examples/hello.zc b/docs/history/10-zc/code/examples/hello.zc
deleted file mode 100644
index f36a810..0000000
--- a/docs/history/10-zc/code/examples/hello.zc
+++ /dev/null
@@ -1 +0,0 @@
-fn main() { puts("hello, world!\n"); return 0; }
diff --git a/docs/history/10-zc/code/examples/lists.zc b/docs/history/10-zc/code/examples/lists.zc
deleted file mode 100644
index 7392752..0000000
--- a/docs/history/10-zc/code/examples/lists.zc
+++ /dev/null
@@ -1,35 +0,0 @@
-// 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 { var b = new(1); b[0] = v; return b as u; }
-fn mklist(cap) -> u { var l = new(cap + 1); l[0] = 0; return l as u; }
-// item arrives as m (it was given down), and goes on as d into the borrowed list
-fn push(m l, d item) { l[l[0] + 1] = item as d; l[0] = l[0] + 1; return 0; }
-fn show(m l)
-{
-	var i = 1;
-	putc('[');
-	while (i <= l[0]) { if (i > 1) putc(' '); putn(l[i][0]); i++; }
-	putc(']');
-	return 0;
-}
-fn squares(n) -> u
-{
-	var l = mklist(n), i = 0;
-	while (i < n) {
-		var b = box(i * i);
-		push(l, b as d);
-		i++;
-	}
-	return l as u;
-}
-fn main()
-{
-	var before = live_objects();
-	{
-		var 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;
-}
diff --git a/docs/history/10-zc/code/examples/repl.zc b/docs/history/10-zc/code/examples/repl.zc
deleted file mode 100644
index 49a8c7b..0000000
--- a/docs/history/10-zc/code/examples/repl.zc
+++ /dev/null
@@ -1,27 +0,0 @@
-// a repl on the resident compiler: each backtick-separated chunk of input is
-// compiled as a function body and run. definitions (fn ...) can be loaded too:
-// a chunk that starts with "fn" goes through load instead of eval.
-var buf[4000];
-fn readchunk()
-{
-	var n = 0, c;
-	while (!eof()) {
-		c = getc();
-		if (c == 96) break;
-		if (n < 3999) { buf[n] = c; n++; }
-	}
-	buf[n] = 0;
-	return n;
-}
-fn main()
-{
-	var q, i;
-	while (!eof()) {
-		readchunk();
-		q = tokens(buf);
-		if (q[0] && q[1] == T_ID && q[2] == intern("fn")) load(q);
-		else eval(q);
-		free(q as d);
-	}
-	return 0;
-}
diff --git a/docs/history/10-zc/code/examples/selfpatch.zc b/docs/history/10-zc/code/examples/selfpatch.zc
deleted file mode 100644
index 35a4843..0000000
--- a/docs/history/10-zc/code/examples/selfpatch.zc
+++ /dev/null
@@ -1,17 +0,0 @@
-// code is data: find the literal 'A' inside f's compiled words and rewrite it.
-// on the jit the store lands on translated code, which gets dropped and
-// retranslated on the next call.
-fn f() { putc('A'); return 0; }
-fn litw(v) { return v + v + 1; }	// how the vm encodes a literal push
-fn main()
-{
-	var p = f;
-	f();
-	while (*p != litw('A')) p++;
-	*p = litw('B');
-	f();
-	*p = litw('C');
-	f();
-	putc(10);
-	return 0;
-}