Handle -- correctly

[cgay]

(The following is unverified internet content. Please verify before acting on it.)

Currently it looks like -- is handled rather poorly in split-args. It just searches for -- as a token and splits the sequence into "clean args" that precede -- and "extra args" that follow --. This doesn't take into account the possibility of supplying "--" as the value of a named option. That is, --foo=-- and --foo -- should be the same thing. (Unlikely to happen? Probably.)

Also, and more importantly, args following -- appear to be glommed onto the value of the final <option> in the parser (or subcommand). Not sure that that makes any sense. Worse yet, add! is used to add the args and add! makes no guarantee where the value will be added to a sequence; beginning? end? middle? Example:

test-positional-option-parsing failed
  #["e", "--", "f"] = p5.option-value failed [#["e", "--", "f"] and #("f", "e") are not =.
  sizes differ (3 and 2), element 0 is the first non-matching element]

Note that the actual parsed value is out of order: #("f", "e")

$ git diff
diff --git a/tests/options-test.dylan b/tests/options-test.dylan
index c2532da..1d8ee27 100644
--- a/tests/options-test.dylan
+++ b/tests/options-test.dylan
@@ -210,10 +210,10 @@ define test test-positional-option-parsing ()
                  help: "h",
                  options: list(make(<flag-option>, names: "flag", help: "h"),
                                p1, p2, p3, p4, p5));
-  assert-no-errors(parse-command-line(cmd, #["a", "b", "c", "d", "e", "f"]));
+  assert-no-errors(parse-command-line(cmd, #["a", "b", "c", "d", "e", "--", "f"]));
   assert-equal("a", p1.option-value);
   assert-equal("b", p2.option-value);
   assert-equal("c", p3.option-value);
   assert-equal("d", p4.option-value);
-  assert-equal(#["e", "f"], p5.option-value);
+  assert-equal(#["e", "--", "f"], p5.option-value);
 end test;

Pretty sure that <positional-option> values with repeated?: #t are lists and that add! adds to the front of a list.