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3.8 mb of sources duplicated from stage to stage and already superseded.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

1 files changed, 0 insertions, 46 deletions

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;
-}