Add repr for InversePresentation

include/libsemigroups/presentation.hpp

@@ -2346,6 +2346,20 @@ namespace libsemigroups {
   template <typename Word>
   std::string to_human_readable_repr(Presentation<Word> const& p);
 
+  //! \ingroup presentations_group
+  //!
+  //! \brief Return a human readable representation of an InversePresentation.
+  //!
+  //! Return a human readable representation of an InversePresentation.
+  //!
+  //! \tparam Word the type of the words in the InversePresentation.
+  //! \param p the InversePresentation.
+  //!
+  //! \exceptions
+  //! \no_libsemigroups_except
+  template <typename Word>
+  std::string to_human_readable_repr(InversePresentation<Word> const& p);
+
   namespace detail {
     template <typename T>
     struct IsPresentationHelper : std::false_type {};

include/libsemigroups/presentation.tpp

@@ -1061,6 +1061,32 @@ namespace libsemigroups {
     return out;
   }
 
+  template <typename Word>
+  std::string to_human_readable_repr(InversePresentation<Word> const& p) {
+    size_t      alphabet_size = p.alphabet().size();
+    size_t      n_rules       = p.rules.size() / 2;
+    std::string out           = "<";
+    if (p.contains_empty_word()) {
+      out += "Monoid ";
+    } else {
+      out += "Semigroup ";
+    }
+    out += "Presentation with inverses on ";
+    if (alphabet_size == 1) {
+      out += "1 letter ";
+    } else {
+      out += std::to_string(alphabet_size) + " letters ";
+    }
+    out += "with ";
+    if (n_rules == 1) {
+      out += "1 rule";
+    } else {
+      out += std::to_string(n_rules) + " rules";
+    }
+    out += ">";
+    return out;
+  }
+
   template <typename Word>
   InversePresentation<Word>&
   InversePresentation<Word>::inverses_no_checks(word_type const& w) {