Merge pull request #344 from rouault/At_least_one_followed_by_exactly_one

Fix parsing of a program that accepts a positional argument with 1:* cardinality followed by another positional argument with 1:1

include/argparse/argparse.hpp

@@ -2336,6 +2336,22 @@ protected:
           }
         }
         auto argument = positional_argument_it++;
+
+        // Deal with the situation of <positional_arg1>... <positional_arg2>
+        if (argument->m_num_args_range.get_min() == 1 &&
+            argument->m_num_args_range.get_max() == (std::numeric_limits<std::size_t>::max)() &&
+            positional_argument_it != std::end(m_positional_arguments) &&
+            std::next(positional_argument_it) == std::end(m_positional_arguments) &&
+            positional_argument_it->m_num_args_range.get_min() == 1 &&
+            positional_argument_it->m_num_args_range.get_max() == 1 ) {
+          if (std::next(it) != end) {
+            positional_argument_it->consume(std::prev(end), end);
+            end = std::prev(end);
+          } else {
+            throw std::runtime_error("Missing " + positional_argument_it->m_names.front());
+          }
+        }
+
         it = argument->consume(it, end);
         continue;
       }

test/test_positional_arguments.cpp

@@ -264,3 +264,40 @@ TEST_CASE("Square a number" * test_suite("positional_arguments")) {
   program.parse_args({"./main", "15"});
   REQUIRE(program.get<double>("square") == 225);
 }
+
+TEST_CASE("At_least_one_followed_by_exactly_one" * test_suite("positional_arguments")) {
+  GIVEN("a program that accepts a positional argument with at_least_one cardinality followed by another positional argument with 1:1") {
+    argparse::ArgumentParser program;
+
+    std::vector<std::string> at_least_one;
+    program.add_argument("at_least_one")
+      .nargs(argparse::nargs_pattern::at_least_one)
+      .store_into(at_least_one);
+
+    std::string exactly_one;
+    program.add_argument("exactly_one")
+      .store_into(exactly_one);
+
+    WHEN("provided one, two") {
+      THEN("parse_args works") {
+          program.parse_args({"./main", "one", "two"});
+          REQUIRE(at_least_one == std::vector<std::string>{"one"});
+          REQUIRE(exactly_one == "two");
+      }
+    }
+
+    WHEN("provided one, two, three") {
+      THEN("parse_args works") {
+          program.parse_args({"./main", "one", "two", "three"});
+          REQUIRE(at_least_one == std::vector<std::string>{"one", "two"});
+          REQUIRE(exactly_one == "three");
+      }
+    }
+
+    WHEN("provided one, two") {
+      THEN("parse_args throws") {
+          REQUIRE_THROWS(program.parse_args({"./main", "one"}));
+      }
+    }
+  }
+}