Fix positional arguments overload

Fixes #83.

Adds an overload for positional arguments taking a
`std::initializer_list`. When using an `initializer_list` with one
argument, the function call is ambiguous matching both `std::string`
and `std::vector<std::string>`.

CHANGELOG.md

@@ -12,6 +12,8 @@ options. The project adheres to semantic versioning.
   when a positional argument could follow an option with an implicit value.
   For example, `--foo value`, where `foo` has an implicit value, will be
   parsed as `--foo=implicit` and a positional argument `value`.
+* Fixed an ambiguous overload in the `parse_positional` function when an
+  `initializer_list` was directly passed.
 
 ## 2.0
 

include/cxxopts.hpp

@@ -1211,6 +1211,9 @@ namespace cxxopts
     void
     parse_positional(std::vector<std::string> options);
 
+    void
+    parse_positional(std::initializer_list<std::string> options);
+
     std::string
     help(const std::vector<std::string>& groups = {""}) const;
 
@@ -1588,7 +1591,7 @@ inline
 void
 Options::parse_positional(std::string option)
 {
-  parse_positional(std::vector<std::string>{option});
+  parse_positional(std::vector<std::string>{std::move(option)});
 }
 
 inline
@@ -1601,6 +1604,13 @@ Options::parse_positional(std::vector<std::string> options)
   m_positional_set.insert(m_positional.begin(), m_positional.end());
 }
 
+inline
+void
+Options::parse_positional(std::initializer_list<std::string> options)
+{
+  parse_positional(std::vector<std::string>(std::move(options)));
+}
+
 inline
 ParseResult
 Options::parse(int& argc, char**& argv)

test/options.cpp

@@ -145,7 +145,7 @@ TEST_CASE("All positional", "[positional]")
   auto argc = av.argc();
   auto argv = av.argv();
 
-  options.parse_positional("positional");
+  options.parse_positional({"positional"});
 
   auto result = options.parse(argc, argv);