cmdopt2: add convenience function for lambda handlers

cmdopt2/args.hpp

@@ -36,6 +36,7 @@ namespace cruft::cmdopt2 {
     template <typename BaseT>
     struct ops_t : argument_t {
         template <typename ValueT>
+        requires (!std::is_convertible_v<ValueT, acceptor1_t>)
         BaseT bind (ValueT&&) = delete;
 
         template <typename ValueT>
@@ -86,6 +87,14 @@ namespace cruft::cmdopt2 {
             return get ();
         }
 
+        BaseT
+        bind (acceptor1_t _acceptor1)
+        {
+            CHECK (!acceptor1);
+            acceptor1 = std::move (_acceptor1);
+            return get ();
+        }
+
         BaseT
         get (void) const
         {

test/cmdopt2.cpp

@@ -262,6 +262,45 @@ test_repeated (cruft::TAP::logger &tap)
 }
 
 
+///////////////////////////////////////////////////////////////////////////////
+static void
+test_bind (cruft::TAP::logger &tap)
+{
+    static constexpr
+    char const* VALUES[] = {
+        "one",
+        "two",
+        "three"
+    };
+
+    std::vector<char const*> values;
+
+    using namespace cruft::cmdopt2;
+    parser p ("test suite");
+    p.add (
+        keyword ("value")
+            .flag ('v')
+            .repeat (true)
+            .bind ([&] (char const *str) { values.push_back (str); })
+    );
+
+    char const *argv[] = { "./cmd", "--value", VALUES[0], "--value", VALUES[1], "--value", VALUES[2] };
+    auto const consumed = p.parse (std::ssize (argv), argv);
+
+    tap.expect_eq (consumed, std::ssize (argv), "bound function: consumed");
+
+    tap.expect (
+        std::equal (
+            std::begin (values),
+            std::end   (values),
+            std::begin (VALUES),
+            std::end   (VALUES)
+        ),
+        "bound function: values"
+    );
+}
+
+
 ///////////////////////////////////////////////////////////////////////////////
 int main ()
 {
@@ -270,5 +309,6 @@ int main ()
     test_presence (tap);
     test_required (tap);
     test_repeated (tap);
+    test_bind (tap);
     return tap.status ();
 }