c++17 compat

Author: CamJN

src/iter.hpp

@@ -5,7 +5,12 @@
 namespace IterGen {
 
 template <typename T> struct Iterator {
+#if defined(__cplusplus) && (__cplusplus == 202002L)
   using iterator_concept [[maybe_unused]] = std::contiguous_iterator_tag;
+#else
+  // strongest type of iterator in c++17
+  using iterator_category = std::random_access_iterator_tag;
+#endif
   using difference_type = std::ptrdiff_t;
   using element_type = T;
   // using value_type = element_type; // ← compiler doesn't seem to need this,
@@ -62,7 +67,16 @@ template <typename T> struct Iterator {
 
   reference operator[](difference_type idx) const { return _ptr[idx]; }
 
+#if defined(__cplusplus) && (__cplusplus == 202002L)
   auto operator<=>(const Iterator &) const = default;
+#else
+  bool operator==(const Iterator &other) const { return other._ptr == _ptr; }
+  bool operator!=(const Iterator &other) const { return other._ptr != _ptr; }
+  bool operator<=(const Iterator &other) const { return other._ptr <= _ptr; }
+  bool operator<(const Iterator &other) const { return other._ptr < _ptr; }
+  bool operator>=(const Iterator &other) const { return other._ptr >= _ptr; }
+  bool operator>(const Iterator &other) const { return other._ptr > _ptr; }
+#endif
 
 private:
   pointer _ptr;

src/main.cpp

@@ -17,8 +17,13 @@ int main(int argc, char *argv[]) {
 
   pid_t pid = (argc > 1) ? std::stoi(argv[argc - 1]) : getpid();
 
+#if defined(__cplusplus) && (__cplusplus == 202002L)
   static_assert(std::contiguous_iterator<Argv::Iterator>);
   static_assert(std::contiguous_iterator<ArgvArgc::Iterator>);
+#else
+  static_assert(std::is_same<std::random_access_iterator_tag, Argv::Iterator::iterator_category>::value);
+  static_assert(std::is_same<std::random_access_iterator_tag, ArgvArgc::Iterator::iterator_category>::value);
+#endif
 
   Argv bytes = Argv::as_bytes(pid, skip, nuls);