Merge branch 'new_python' into 'master'

New "contextual" system of Python wrappers

See merge request SymbioticEDA/nextpnr!4

6 files changed, 468 insertions, 180 deletions

diff --git a/common/nextpnr.cc b/common/nextpnr.cc
index a197eaff..3861e5fe 100644
--- a/common/nextpnr.cc
+++ b/common/nextpnr.cc
@@ -27,8 +27,6 @@ assertion_failure::assertion_failure(std::string msg, std::string expr_str, std:
 {
 }
 
-std::unordered_set<BaseCtx *> IdString::global_ctx;
-
 void IdString::set(const BaseCtx *ctx, const std::string &s)
 {
     auto it = ctx->idstring_str_to_idx->find(s);
diff --git a/common/nextpnr.h b/common/nextpnr.h
index 6a45875b..ec0c2f9f 100644
--- a/common/nextpnr.h
+++ b/common/nextpnr.h
@@ -118,16 +118,6 @@ struct IdString
     bool operator!=(const IdString &other) const { return index != other.index; }
 
     bool empty() const { return index == 0; }
-
-    // --- deprecated old API ---
-
-    static std::unordered_set<BaseCtx *> global_ctx;
-
-    NPNR_DEPRECATED const std::string &global_str() const
-    {
-        assert(global_ctx.size() == 1);
-        return str(*global_ctx.begin());
-    }
 };
 
 NEXTPNR_NAMESPACE_END
@@ -252,8 +242,6 @@ struct BaseCtx
 
     BaseCtx()
     {
-        IdString::global_ctx.insert(this);
-
         idstring_str_to_idx = new std::unordered_map<std::string, int>;
         idstring_idx_to_str = new std::vector<const std::string *>;
         IdString::initialize_add(this, "", 0);
@@ -262,7 +250,6 @@ struct BaseCtx
 
     ~BaseCtx()
     {
-        IdString::global_ctx.erase(this);
         delete idstring_str_to_idx;
         delete idstring_idx_to_str;
     }
diff --git a/common/pybindings.cc b/common/pybindings.cc
index e9ceca51..9bca307c 100644
--- a/common/pybindings.cc
+++ b/common/pybindings.cc
@@ -21,6 +21,7 @@
 #ifndef NO_PYTHON
 
 #include "pybindings.h"
+#include "arch_pybindings.h"
 #include "jsonparse.h"
 #include "nextpnr.h"
 
@@ -61,8 +62,18 @@ Context *load_design_shim(std::string filename, ArchArgs args)
     return d;
 }
 
+void translate_assertfail(const assertion_failure &e)
+{
+    // Use the Python 'C' API to set up an exception object
+    PyErr_SetString(PyExc_AssertionError, e.what());
+}
+
 BOOST_PYTHON_MODULE(MODULE_NAME)
 {
+    register_exception_translator<assertion_failure>(&translate_assertfail);
+
+    using namespace PythonConversion;
+
     class_<GraphicElement>("GraphicElement")
             .def_readwrite("type", &GraphicElement::type)
             .def_readwrite("x1", &GraphicElement::x1)
@@ -71,59 +82,73 @@ BOOST_PYTHON_MODULE(MODULE_NAME)
             .def_readwrite("y2", &GraphicElement::y2)
             .def_readwrite("text", &GraphicElement::text);
 
-    class_<PortRef>("PortRef").def_readwrite("cell", &PortRef::cell).def_readwrite("port", &PortRef::port);
-
-    class_<NetInfo, NetInfo *, boost::noncopyable>("NetInfo")
-            .def_readwrite("name", &NetInfo::name)
-            .def_readwrite("driver", &NetInfo::driver)
-            .def_readwrite("users", &NetInfo::users)
-            .def_readwrite("attrs", &NetInfo::attrs)
-            .def_readwrite("wires", &NetInfo::wires);
-
-    WRAP_MAP(decltype(NetInfo::attrs), "IdStrMap");
-
-    class_<std::vector<PortRef>>("PortRefVector").def(vector_indexing_suite<std::vector<PortRef>>());
-
     enum_<PortType>("PortType")
             .value("PORT_IN", PORT_IN)
             .value("PORT_OUT", PORT_OUT)
             .value("PORT_INOUT", PORT_INOUT)
             .export_values();
 
-    class_<PortInfo>("PortInfo")
-            .def_readwrite("name", &PortInfo::name)
-            .def_readwrite("net", &PortInfo::net)
-            .def_readwrite("type", &PortInfo::type);
-
-    class_<CellInfo, CellInfo *>("CellInfo")
-            .def_readwrite("name", &CellInfo::name)
-            .def_readwrite("type", &CellInfo::type)
-            .def_readwrite("ports", &CellInfo::ports)
-            .def_readwrite("attrs", &CellInfo::attrs)
-            .def_readwrite("params", &CellInfo::params)
-            .def_readwrite("bel", &CellInfo::bel)
-            .def_readwrite("pins", &CellInfo::pins);
-
-    WRAP_MAP(decltype(CellInfo::ports), "IdPortMap");
-    // WRAP_MAP(decltype(CellInfo::pins), "IdIdMap");
-
-    class_<BaseCtx, BaseCtx *, boost::noncopyable>("BaseCtx", no_init)
-            .add_property("nets", make_getter(&Context::nets, return_internal_reference<>()))
-            .add_property("cells", make_getter(&Context::cells, return_internal_reference<>()));
-
-    WRAP_MAP_UPTR(decltype(Context::nets), "IdNetMap");
-    WRAP_MAP_UPTR(decltype(Context::cells), "IdCellMap");
+    typedef std::unordered_map<IdString, std::string> AttrMap;
+    typedef std::unordered_map<IdString, PortInfo> PortMap;
+    typedef std::unordered_map<IdString, IdString> PinMap;
+
+    class_<BaseCtx, BaseCtx *, boost::noncopyable>("BaseCtx", no_init);
+
+    auto ci_cls = class_<ContextualWrapper<CellInfo &>>("CellInfo", no_init);
+    readwrite_wrapper<CellInfo &, typeof(&CellInfo::name), &CellInfo::name, conv_to_str<IdString>,
+                      conv_from_str<IdString>>::def_wrap(ci_cls, "name");
+    readwrite_wrapper<CellInfo &, typeof(&CellInfo::type), &CellInfo::type, conv_to_str<IdString>,
+                      conv_from_str<IdString>>::def_wrap(ci_cls, "type");
+    readonly_wrapper<CellInfo &, typeof(&CellInfo::attrs), &CellInfo::attrs, wrap_context<AttrMap &>>::def_wrap(
+            ci_cls, "attrs");
+    readonly_wrapper<CellInfo &, typeof(&CellInfo::params), &CellInfo::params, wrap_context<AttrMap &>>::def_wrap(
+            ci_cls, "params");
+    readonly_wrapper<CellInfo &, typeof(&CellInfo::ports), &CellInfo::ports, wrap_context<PortMap &>>::def_wrap(
+            ci_cls, "ports");
+    readwrite_wrapper<CellInfo &, typeof(&CellInfo::bel), &CellInfo::bel, conv_to_str<BelId>,
+                      conv_from_str<BelId>>::def_wrap(ci_cls, "bel");
+    readwrite_wrapper<CellInfo &, typeof(&CellInfo::belStrength), &CellInfo::belStrength, pass_through<PlaceStrength>,
+                      pass_through<PlaceStrength>>::def_wrap(ci_cls, "belStrength");
+    readonly_wrapper<CellInfo &, typeof(&CellInfo::pins), &CellInfo::pins, wrap_context<PinMap &>>::def_wrap(ci_cls,
+                                                                                                             "pins");
+
+    auto pi_cls = class_<ContextualWrapper<PortInfo &>>("PortInfo", no_init);
+    readwrite_wrapper<PortInfo &, typeof(&PortInfo::name), &PortInfo::name, conv_to_str<IdString>,
+                      conv_from_str<IdString>>::def_wrap(pi_cls, "name");
+    readonly_wrapper<PortInfo &, typeof(&PortInfo::net), &PortInfo::net, deref_and_wrap<NetInfo>>::def_wrap(pi_cls,
+                                                                                                            "net");
+    readwrite_wrapper<PortInfo &, typeof(&PortInfo::type), &PortInfo::type, pass_through<PortType>,
+                      pass_through<PortType>>::def_wrap(pi_cls, "type");
+
+    typedef std::vector<PortRef> PortVector;
+    typedef std::unordered_map<WireId, PipMap> WireMap;
+
+    auto ni_cls = class_<ContextualWrapper<NetInfo &>>("NetInfo", no_init);
+    readwrite_wrapper<NetInfo &, typeof(&NetInfo::name), &NetInfo::name, conv_to_str<IdString>,
+                      conv_from_str<IdString>>::def_wrap(ni_cls, "name");
+    readwrite_wrapper<NetInfo &, typeof(&NetInfo::driver), &NetInfo::driver, wrap_context<PortRef &>,
+                      unwrap_context<PortRef &>>::def_wrap(ni_cls, "driver");
+    readonly_wrapper<NetInfo &, typeof(&NetInfo::users), &NetInfo::users, wrap_context<PortVector &>>::def_wrap(
+            ni_cls, "users");
+    readonly_wrapper<NetInfo &, typeof(&NetInfo::wires), &NetInfo::wires, wrap_context<WireMap &>>::def_wrap(ni_cls,
+                                                                                                             "wires");
+
+    auto pr_cls = class_<ContextualWrapper<PortRef &>>("PortRef", no_init);
+    readonly_wrapper<PortRef &, typeof(&PortRef::cell), &PortRef::cell, deref_and_wrap<CellInfo>>::def_wrap(pr_cls,
+                                                                                                            "cell");
+    readwrite_wrapper<PortRef &, typeof(&PortRef::port), &PortRef::port, conv_to_str<IdString>,
+                      conv_from_str<IdString>>::def_wrap(pr_cls, "port");
+    readwrite_wrapper<PortRef &, typeof(&PortRef::budget), &PortRef::budget, pass_through<delay_t>,
+                      pass_through<delay_t>>::def_wrap(pr_cls, "budget");
 
     def("parse_json", parse_json_shim);
     def("load_design", load_design_shim, return_value_policy<manage_new_object>());
 
-    class_<IdString>("IdString")
-            .def("__str__", &IdString::global_str, return_value_policy<copy_const_reference>())
-            .def(self < self)
-            .def(self == self);
-    arch_wrap_python();
+    WRAP_MAP(AttrMap, pass_through<std::string>, "AttrMap");
+    WRAP_MAP(PortMap, wrap_context<PortInfo &>, "PortMap");
+    WRAP_MAP(PinMap, conv_to_str<IdString>, "PinMap");
 
-    class_<Context, Context *, bases<Arch>, boost::noncopyable>("Context", no_init).def("checksum", &Context::checksum);
+    arch_wrap_python();
 }
 
 static wchar_t *program;
diff --git a/common/pybindings.h b/common/pybindings.h
index 1565a138..c4d84442 100644
--- a/common/pybindings.h
+++ b/common/pybindings.h
@@ -36,50 +36,6 @@ NEXTPNR_NAMESPACE_BEGIN
 
 using namespace boost::python;
 
-/*
-A wrapper to enable custom type/ID to/from string conversions
- */
-template <typename T> struct string_wrapper
-{
-    template <typename F> struct from_pystring_converter
-    {
-        from_pystring_converter()
-        {
-            converter::registry::push_back(&convertible, &construct, boost::python::type_id<T>());
-        };
-
-        static void *convertible(PyObject *object) { return PyUnicode_Check(object) ? object : 0; }
-
-        static void construct(PyObject *object, converter::rvalue_from_python_stage1_data *data)
-        {
-            const wchar_t *value = PyUnicode_AsUnicode(object);
-            const std::wstring value_ws(value);
-            if (value == 0)
-                throw_error_already_set();
-            void *storage = ((boost::python::converter::rvalue_from_python_storage<T> *)data)->storage.bytes;
-            new (storage) T(fn(std::string(value_ws.begin(), value_ws.end())));
-            data->convertible = storage;
-        }
-
-        static F fn;
-    };
-
-    template <typename F> struct to_str_wrapper
-    {
-        static F fn;
-
-        std::string str(T &x) { return fn(x); }
-    };
-
-    template <typename F1, typename F2> static void wrap(const char *type_name, F1 to_str_fn, F2 from_str_fn)
-    {
-        from_pystring_converter<F2>::fn = from_str_fn;
-        from_pystring_converter<F2>();
-        to_str_wrapper<F1>::fn = to_str_fn;
-        class_<T>(type_name, no_init).def("__str__", to_str_wrapper<F1>::str);
-    };
-};
-
 std::string parse_python_exception();
 
 template <typename Tn> void python_export_global(const char *name, Tn &x)
@@ -106,6 +62,25 @@ void deinit_python();
 
 void execute_python_file(const char *python_file);
 
+// Defauld IdString conversions
+namespace PythonConversion {
+
+template <> struct string_converter<IdString>
+{
+    inline IdString from_str(Context *ctx, std::string name) { return ctx->id(name); }
+
+    inline std::string to_str(Context *ctx, IdString id) { return id.str(ctx); }
+};
+
+template <> struct string_converter<const IdString>
+{
+    inline IdString from_str(Context *ctx, std::string name) { return ctx->id(name); }
+
+    inline std::string to_str(Context *ctx, IdString id) { return id.str(ctx); }
+};
+
+} // namespace PythonConversion
+
 NEXTPNR_NAMESPACE_END
 
 #endif /* end of include guard: COMMON_PYBINDINGS_HH */
diff --git a/common/pycontainers.h b/common/pycontainers.h
index 917f49e9..f4251558 100644
--- a/common/pycontainers.h
+++ b/common/pycontainers.h
@@ -24,10 +24,12 @@
 #include <boost/python.hpp>
 #include <boost/python/suite/indexing/map_indexing_suite.hpp>
 #include <boost/python/suite/indexing/vector_indexing_suite.hpp>
+#include <sstream>
 #include <stdexcept>
 #include <type_traits>
 #include <utility>
 #include "nextpnr.h"
+#include "pywrappers.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 
@@ -37,18 +39,22 @@ inline void KeyError() { PyErr_SetString(PyExc_KeyError, "Key not found"); }
 
 /*
 A wrapper for a Pythonised nextpnr Iterator. The actual class wrapped is a
-pair<Iterator, Iterator> containing (current, end)
+pair<Iterator, Iterator> containing (current, end), wrapped in a ContextualWrapper
+
 */
 
-template <typename T, typename P> struct iterator_wrapper
+template <typename T, typename P, typename value_conv = PythonConversion::pass_through<T>> struct iterator_wrapper
 {
     typedef decltype(*(std::declval<T>())) value_t;
 
-    static value_t next(std::pair<T, T> &iter)
+    typedef PythonConversion::ContextualWrapper<std::pair<T, T>> wrapped_iter_t;
+    using return_t = typename value_conv::ret_type;
+
+    static return_t next(wrapped_iter_t &iter)
     {
-        if (iter.first != iter.second) {
-            value_t val = *iter.first;
-            ++iter.first;
+        if (iter.base.first != iter.base.second) {
+            return_t val = value_conv()(iter.ctx, *iter.base.first);
+            ++iter.base.first;
             return val;
         } else {
             PyErr_SetString(PyExc_StopIteration, "End of range reached");
@@ -61,7 +67,7 @@ template <typename T, typename P> struct iterator_wrapper
 
     static void wrap(const char *python_name)
     {
-        class_<std::pair<T, T>>(python_name, no_init).def("__next__", next, P());
+        class_<wrapped_iter_t>(python_name, no_init).def("__next__", next, P());
     }
 };
 
@@ -71,22 +77,46 @@ and end() which return iterator-like objects supporting ++, * and !=
 Full STL iterator semantics are not required, unlike the standard Boost wrappers
 */
 
-template <typename T, typename P = return_value_policy<return_by_value>> struct range_wrapper
+template <typename T, typename P = return_value_policy<return_by_value>,
+          typename value_conv = PythonConversion::pass_through<T>>
+struct range_wrapper
 {
     typedef decltype(std::declval<T>().begin()) iterator_t;
+    typedef decltype(*(std::declval<iterator_t>())) value_t;
+    typedef typename PythonConversion::ContextualWrapper<T> wrapped_range;
+    typedef typename PythonConversion::ContextualWrapper<std::pair<iterator_t, iterator_t>> wrapped_pair;
+    static wrapped_pair iter(wrapped_range &range)
+    {
+        return wrapped_pair(range.ctx, std::make_pair(range.base.begin(), range.base.end()));
+    }
 
-    static std::pair<iterator_t, iterator_t> iter(T &range) { return std::make_pair(range.begin(), range.end()); }
+    static std::string repr(wrapped_range &range)
+    {
+        PythonConversion::string_converter<value_t> conv;
+        bool first = true;
+        std::stringstream ss;
+        ss << "[";
+        for (const auto &item : range.base) {
+            if (!first)
+                ss << ", ";
+            ss << "'" << conv.to_str(range.ctx, item) << "'";
+            first = false;
+        }
+        ss << "]";
+        return ss.str();
+    }
 
     static void wrap(const char *range_name, const char *iter_name)
     {
-        class_<T>(range_name, no_init).def("__iter__", iter);
-        iterator_wrapper<iterator_t, P>().wrap(iter_name);
+        class_<wrapped_range>(range_name, no_init).def("__iter__", iter).def("__repr__", repr);
+        iterator_wrapper<iterator_t, P, value_conv>().wrap(iter_name);
     }
 
-    typedef iterator_wrapper<iterator_t, P> iter_wrap;
+    typedef iterator_wrapper<iterator_t, P, value_conv> iter_wrap;
 };
 
-#define WRAP_RANGE(t) range_wrapper<t##Range>().wrap(#t "Range", #t "Iterator")
+#define WRAP_RANGE(t, conv)                                                                                            \
+    range_wrapper<t##Range, return_value_policy<return_by_value>, conv>().wrap(#t "Range", #t "Iterator")
 
 /*
 Wrapper for a pair, allows accessing either using C++-style members (.first and
@@ -158,20 +188,23 @@ template <typename T1, typename T2> struct pair_wrapper
 /*
 Special case of above for map key/values
  */
-template <typename T1, typename T2> struct map_pair_wrapper
+template <typename T1, typename T2, typename value_conv> struct map_pair_wrapper
 {
     typedef std::pair<T1, T2> T;
+    typedef PythonConversion::ContextualWrapper<T &> wrapped_pair;
+    typedef typename T::second_type V;
 
     struct pair_iterator_wrapper
     {
-        static object next(std::pair<T &, int> &iter)
+        static object next(std::pair<wrapped_pair &, int> &iter)
         {
             if (iter.second == 0) {
                 iter.second++;
-                return object(iter.first.first);
+                return object(PythonConversion::string_converter<typeof(iter.first.base.first)>().to_str(
+                        iter.first.ctx, iter.first.base.first));
             } else if (iter.second == 1) {
                 iter.second++;
-                return object(iter.first.second);
+                return object(value_conv()(iter.first.ctx, iter.first.base.second));
             } else {
                 PyErr_SetString(PyExc_StopIteration, "End of range reached");
                 boost::python::throw_error_already_set();
@@ -183,30 +216,37 @@ template <typename T1, typename T2> struct map_pair_wrapper
 
         static void wrap(const char *python_name)
         {
-            class_<std::pair<T &, int>>(python_name, no_init).def("__next__", next);
+            class_<std::pair<wrapped_pair &, int>>(python_name, no_init).def("__next__", next);
         }
     };
 
-    static object get(T &x, int i)
+    static object get(wrapped_pair &x, int i)
     {
         if ((i >= 2) || (i < 0))
             KeyError();
-        return (i == 1) ? object(x.second) : object(x.first);
+        return (i == 1) ? object(value_conv()(x.ctx, x.base.second)) : object(x.base.first);
     }
 
-    static int len(T &x) { return 2; }
+    static int len(wrapped_pair &x) { return 2; }
 
-    static std::pair<T &, int> iter(T &x) { return std::make_pair(boost::ref(x), 0); };
+    static std::pair<wrapped_pair &, int> iter(wrapped_pair &x) { return std::make_pair(boost::ref(x), 0); };
+
+    static std::string first_getter(wrapped_pair &t)
+    {
+        return PythonConversion::string_converter<typeof(t.base.first)>().to_str(t.ctx, t.base.first);
+    }
+
+    static typename value_conv::ret_type second_getter(wrapped_pair &t) { return value_conv()(t.ctx, t.base.second); }
 
     static void wrap(const char *pair_name, const char *iter_name)
     {
         pair_iterator_wrapper::wrap(iter_name);
-        class_<T>(pair_name, no_init)
+        class_<wrapped_pair>(pair_name, no_init)
                 .def("__iter__", iter)
                 .def("__len__", len)
                 .def("__getitem__", get)
-                .def_readonly("first", &T::first)
-                .def_readwrite("second", &T::second);
+                .add_property("first", first_getter)
+                .add_property("second", second_getter);
     }
 };
 
@@ -214,26 +254,35 @@ template <typename T1, typename T2> struct map_pair_wrapper
 Wrapper for a map, either an unordered_map, regular map or dict
  */
 
-template <typename T> struct map_wrapper
+template <typename T, typename value_conv> struct map_wrapper
 {
     typedef typename std::remove_cv<typename std::remove_reference<typename T::key_type>::type>::type K;
     typedef typename T::mapped_type V;
+    typedef typename value_conv::ret_type wrapped_V;
     typedef typename T::value_type KV;
+    typedef typename PythonConversion::ContextualWrapper<T &> wrapped_map;
 
-    static V &get(T &x, K const &i)
+    static wrapped_V get(wrapped_map &x, std::string const &i)
     {
-        if (x.find(i) != x.end())
-            return x.at(i);
+        K k = PythonConversion::string_converter<K>().from_str(x.ctx, i);
+        if (x.base.find(k) != x.base.end())
+            return value_conv()(x.ctx, x.base.at(k));
         KeyError();
         std::terminate();
     }
 
-    static void set(T &x, K const &i, V &v) { x[i] = v; }
+    static void set(wrapped_map &x, std::string const &i, V const &v)
+    {
+        x.base[PythonConversion::string_converter<K>().from_str(x.ctx, i)] = v;
+    }
+
+    static size_t len(wrapped_map &x) { return x.base.size(); }
 
-    static void del(T const &x, K const &i)
+    static void del(T const &x, std::string const &i)
     {
-        if (x.find(i) != x.end())
-            x.erase(i);
+        K k = PythonConversion::string_converter<K>().from_str(x.ctx, i);
+        if (x.base.find(k) != x.base.end())
+            x.base.erase(k);
         else
             KeyError();
         std::terminate();
@@ -241,13 +290,13 @@ template <typename T> struct map_wrapper
 
     static void wrap(const char *map_name, const char *kv_name, const char *kv_iter_name, const char *iter_name)
     {
-        map_pair_wrapper<typename KV::first_type, typename KV::second_type>::wrap(kv_name, kv_iter_name);
-        typedef range_wrapper<T, return_value_policy<copy_non_const_reference>> rw;
+        map_pair_wrapper<typename KV::first_type, typename KV::second_type, value_conv>::wrap(kv_name, kv_iter_name);
+        typedef range_wrapper<T &, return_value_policy<return_by_value>, PythonConversion::wrap_context<KV &>> rw;
         typename rw::iter_wrap().wrap(iter_name);
-        class_<T>(map_name, no_init)
+        class_<wrapped_map>(map_name, no_init)
                 .def("__iter__", rw::iter)
-                .def("__len__", &T::size)
-                .def("__getitem__", get, return_internal_reference<>())
+                .def("__len__", len)
+                .def("__getitem__", get)
                 .def("__setitem__", set, with_custodian_and_ward<1, 2>());
     }
 };
@@ -258,17 +307,20 @@ Special case of above for map key/values where value is a unique_ptr
 template <typename T1, typename T2> struct map_pair_wrapper_uptr
 {
     typedef std::pair<T1, T2> T;
+    typedef PythonConversion::ContextualWrapper<T &> wrapped_pair;
     typedef typename T::second_type::element_type V;
+
     struct pair_iterator_wrapper
     {
-        static object next(std::pair<T &, int> &iter)
+        static object next(std::pair<wrapped_pair &, int> &iter)
         {
             if (iter.second == 0) {
                 iter.second++;
-                return object(iter.first.first);
+                return object(PythonConversion::string_converter<typeof(iter.first.base.first)>().to_str(
+                        iter.first.ctx, iter.first.base.first));
             } else if (iter.second == 1) {
                 iter.second++;
-                return object(iter.first.second.get());
+                return object(PythonConversion::ContextualWrapper<V &>(iter.first.ctx, *iter.first.base.second.get()));
             } else {
                 PyErr_SetString(PyExc_StopIteration, "End of range reached");
                 boost::python::throw_error_already_set();
@@ -280,32 +332,41 @@ template <typename T1, typename T2> struct map_pair_wrapper_uptr
 
         static void wrap(const char *python_name)
         {
-            class_<std::pair<T &, int>>(python_name, no_init).def("__next__", next);
+            class_<std::pair<wrapped_pair &, int>>(python_name, no_init).def("__next__", next);
         }
     };
 
-    static object get(T &x, int i)
+    static object get(wrapped_pair &x, int i)
     {
         if ((i >= 2) || (i < 0))
             KeyError();
-        return (i == 1) ? object(x.second.get()) : object(x.first);
+        return (i == 1) ? object(PythonConversion::ContextualWrapper<V &>(x.ctx, *x.base.second.get()))
+                        : object(x.base.first);
     }
 
-    static int len(T &x) { return 2; }
+    static int len(wrapped_pair &x) { return 2; }
 
-    static std::pair<T &, int> iter(T &x) { return std::make_pair(boost::ref(x), 0); };
+    static std::pair<wrapped_pair &, int> iter(wrapped_pair &x) { return std::make_pair(boost::ref(x), 0); };
 
-    static V &second_getter(T &t) { return *t.second.get(); }
+    static std::string first_getter(wrapped_pair &t)
+    {
+        return PythonConversion::string_converter<typeof(t.base.first)>().to_str(t.ctx, t.base.first);
+    }
+
+    static PythonConversion::ContextualWrapper<V &> second_getter(wrapped_pair &t)
+    {
+        return PythonConversion::ContextualWrapper<V &>(t.ctx, *t.base.second.get());
+    }
 
     static void wrap(const char *pair_name, const char *iter_name)
     {
         pair_iterator_wrapper::wrap(iter_name);
-        class_<T, boost::noncopyable>(pair_name, no_init)
+        class_<wrapped_pair>(pair_name, no_init)
                 .def("__iter__", iter)
                 .def("__len__", len)
                 .def("__getitem__", get)
-                .def_readonly("first", &T::first)
-                .add_property("second", make_function(second_getter, return_internal_reference<>()));
+                .add_property("first", first_getter)
+                .add_property("second", second_getter);
     }
 };
 
@@ -317,22 +378,31 @@ template <typename T> struct map_wrapper_uptr
 {
     typedef typename std::remove_cv<typename std::remove_reference<typename T::key_type>::type>::type K;
     typedef typename T::mapped_type::pointer V;
+    typedef typename T::mapped_type::element_type &Vr;
     typedef typename T::value_type KV;
+    typedef typename PythonConversion::ContextualWrapper<T &> wrapped_map;
 
-    static V get(T &x, K const &i)
+    static PythonConversion::ContextualWrapper<Vr> get(wrapped_map &x, std::string const &i)
     {
-        if (x.find(i) != x.end())
-            return x.at(i).get();
+        K k = PythonConversion::string_converter<K>().from_str(x.ctx, i);
+        if (x.base.find(k) != x.base.end())
+            return PythonConversion::ContextualWrapper<Vr>(x.ctx, *x.base.at(k).get());
         KeyError();
         std::terminate();
     }
 
-    static void set(T &x, K const &i, V const &v) { x[i] = typename T::mapped_type(v); }
+    static void set(wrapped_map &x, std::string const &i, V const &v)
+    {
+        x.base[PythonConversion::string_converter<K>().from_str(x.ctx, i)] = typename T::mapped_type(v);
+    }
+
+    static size_t len(wrapped_map &x) { return x.base.size(); }
 
-    static void del(T const &x, K const &i)
+    static void del(T const &x, std::string const &i)
     {
-        if (x.find(i) != x.end())
-            x.erase(i);
+        K k = PythonConversion::string_converter<K>().from_str(x.ctx, i);
+        if (x.base.find(k) != x.base.end())
+            x.base.erase(k);
         else
             KeyError();
         std::terminate();
@@ -341,17 +411,18 @@ template <typename T> struct map_wrapper_uptr
     static void wrap(const char *map_name, const char *kv_name, const char *kv_iter_name, const char *iter_name)
     {
         map_pair_wrapper_uptr<typename KV::first_type, typename KV::second_type>::wrap(kv_name, kv_iter_name);
-        typedef range_wrapper<T, return_internal_reference<>> rw;
+        typedef range_wrapper<T &, return_value_policy<return_by_value>, PythonConversion::wrap_context<KV &>> rw;
         typename rw::iter_wrap().wrap(iter_name);
-        class_<T, boost::noncopyable>(map_name, no_init)
+        class_<wrapped_map>(map_name, no_init)
                 .def("__iter__", rw::iter)
-                .def("__len__", &T::size)
-                .def("__getitem__", get, return_internal_reference<>())
+                .def("__len__", len)
+                .def("__getitem__", get)
                 .def("__setitem__", set, with_custodian_and_ward<1, 2>());
     }
 };
 
-#define WRAP_MAP(t, name) map_wrapper<t>().wrap(#name, #name "KeyValue", #name "KeyValueIter", #name "Iterator")
+#define WRAP_MAP(t, conv, name)                                                                                        \
+    map_wrapper<t, conv>().wrap(#name, #name "KeyValue", #name "KeyValueIter", #name "Iterator")
 #define WRAP_MAP_UPTR(t, name)                                                                                         \
     map_wrapper_uptr<t>().wrap(#name, #name "KeyValue", #name "KeyValueIter", #name "Iterator")
 
diff --git a/common/pywrappers.h b/common/pywrappers.h
index 2c91f26f..725caca8 100644
--- a/common/pywrappers.h
+++ b/common/pywrappers.h
@@ -41,65 +41,297 @@ template <typename T> struct ContextualWrapper
     Context *ctx;
     T base;
 
-    ContextualWrapper(Context *c, T &&x) : ctx(c), base(x){};
+    inline ContextualWrapper(Context *c, T x) : ctx(c), base(x){};
 
-    operator T() { return base; };
+    inline operator T() { return base; };
     typedef T base_type;
 };
 
+template <typename T> struct WrapIfNotContext
+{
+    typedef ContextualWrapper<T> maybe_wrapped_t;
+};
+
+template <> struct WrapIfNotContext<Context>
+{
+    typedef Context maybe_wrapped_t;
+};
+
+template <typename T> inline Context *get_ctx(typename WrapIfNotContext<T>::maybe_wrapped_t &wrp_ctx)
+{
+    return wrp_ctx.ctx;
+}
+
+template <> inline Context *get_ctx<Context>(WrapIfNotContext<Context>::maybe_wrapped_t &unwrp_ctx)
+{
+    return &unwrp_ctx;
+}
+
+template <typename T> inline T &get_base(typename WrapIfNotContext<T>::maybe_wrapped_t &wrp_ctx)
+{
+    return wrp_ctx.base;
+}
+
+template <> inline Context &get_base<Context>(WrapIfNotContext<Context>::maybe_wrapped_t &unwrp_ctx)
+{
+    return unwrp_ctx;
+}
+
 template <typename T> ContextualWrapper<T> wrap_ctx(Context *ctx, T x) { return ContextualWrapper<T>(ctx, x); }
 
 // Dummy class, to be implemented by users
-template <typename T> class string_converter;
+template <typename T> struct string_converter;
+
+class bad_wrap
+{
+};
 
 // Action options
-template <typename T> class do_nothing
+template <typename T> struct pass_through
 {
-    T operator()(Context *ctx, T x) { return x; }
+    inline T operator()(Context *ctx, T x) { return x; }
 
     using ret_type = T;
     using arg_type = T;
 };
 
-template <typename T> class wrap_context
+template <typename T> struct wrap_context
 {
-    ContextualWrapper<T> operator()(Context *ctx, T x) { return ContextualWrapper<T>(ctx, x); }
+    inline ContextualWrapper<T> operator()(Context *ctx, T x) { return ContextualWrapper<T>(ctx, x); }
+
     using arg_type = T;
     using ret_type = ContextualWrapper<T>;
 };
 
-template <typename T> class unwrap_context
+template <typename T> struct unwrap_context
 {
-    T operator()(Context *ctx, ContextualWrapper<T> x) { return x.base; }
+    inline T operator()(Context *ctx, ContextualWrapper<T> x) { return x.base; }
+
     using ret_type = T;
     using arg_type = ContextualWrapper<T>;
 };
 
-template <typename T> class conv_from_string
+template <typename T> struct conv_from_str
 {
-    T operator()(Context *ctx, std::string x) { return string_converter<T>().from_str(ctx, x); }
+    inline T operator()(Context *ctx, std::string x) { return string_converter<T>().from_str(ctx, x); }
+
     using ret_type = T;
     using arg_type = std::string;
 };
 
-template <typename T> class conv_to_string
+template <typename T> struct conv_to_str
 {
-    std::string operator()(Context *ctx, T x) { return string_converter<T>().to_str(ctx, x); }
+    inline std::string operator()(Context *ctx, T x) { return string_converter<T>().to_str(ctx, x); }
+
     using ret_type = std::string;
     using arg_type = T;
 };
 
+template <typename T> struct deref_and_wrap
+{
+    inline ContextualWrapper<T &> operator()(Context *ctx, T *x)
+    {
+        if (x == nullptr)
+            throw bad_wrap();
+        return ContextualWrapper<T &>(ctx, *x);
+    }
+
+    using arg_type = T *;
+    using ret_type = ContextualWrapper<T &>;
+};
+
 // Function wrapper
-// Example: one parameter, one return
-template <typename Class, typename FuncT, FuncT fn, typename rv_conv, typename arg1_conv> struct function_wrapper
+// Zero parameters, one return
+template <typename Class, typename FuncT, FuncT fn, typename rv_conv> struct fn_wrapper_0a
 {
-    using class_type = ContextualWrapper<Class>;
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_result_type = typename rv_conv::ret_type;
+
+    static conv_result_type wrapped_fn(class_type &cls)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        return rv_conv()(ctx, (base.*fn)());
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+};
+
+// One parameter, one return
+template <typename Class, typename FuncT, FuncT fn, typename rv_conv, typename arg1_conv> struct fn_wrapper_1a
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
     using conv_result_type = typename rv_conv::ret_type;
     using conv_arg1_type = typename arg1_conv::arg_type;
 
     static conv_result_type wrapped_fn(class_type &cls, conv_arg1_type arg1)
     {
-        return rv_conv()(cls.ctx, cls.base.*fn(arg1_conv()(cls.ctx, arg1)));
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        return rv_conv()(ctx, (base.*fn)(arg1_conv()(ctx, arg1)));
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+};
+
+// Two parameters, one return
+template <typename Class, typename FuncT, FuncT fn, typename rv_conv, typename arg1_conv, typename arg2_conv>
+struct fn_wrapper_2a
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_result_type = typename rv_conv::ret_type;
+    using conv_arg1_type = typename arg1_conv::arg_type;
+    using conv_arg2_type = typename arg2_conv::arg_type;
+
+    static conv_result_type wrapped_fn(class_type &cls, conv_arg1_type arg1, conv_arg2_type arg2)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        return rv_conv()(ctx, (base.*fn)(arg1_conv()(ctx, arg1), arg2_conv()(ctx, arg2)));
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+};
+
+// Three parameters, one return
+template <typename Class, typename FuncT, FuncT fn, typename rv_conv, typename arg1_conv, typename arg2_conv,
+          typename arg3_conv>
+struct fn_wrapper_3a
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_result_type = typename rv_conv::ret_type;
+    using conv_arg1_type = typename arg1_conv::arg_type;
+    using conv_arg2_type = typename arg2_conv::arg_type;
+    using conv_arg3_type = typename arg3_conv::arg_type;
+
+    static conv_result_type wrapped_fn(class_type &cls, conv_arg1_type arg1, conv_arg2_type arg2, conv_arg3_type arg3)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        return rv_conv()(ctx, (base.*fn)(arg1_conv()(ctx, arg1), arg2_conv()(ctx, arg2), arg3_conv()(ctx, arg3)));
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+};
+
+// Zero parameters void
+template <typename Class, typename FuncT, FuncT fn> struct fn_wrapper_0a_v
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+
+    static void wrapped_fn(class_type &cls)
+    {
+        Class &base = get_base<Class>(cls);
+        return (base.*fn)();
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+};
+
+// One parameter, void
+template <typename Class, typename FuncT, FuncT fn, typename arg1_conv> struct fn_wrapper_1a_v
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_arg1_type = typename arg1_conv::arg_type;
+
+    static void wrapped_fn(class_type &cls, conv_arg1_type arg1)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        return (base.*fn)(arg1_conv()(ctx, arg1));
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+};
+
+// Two parameters, one return
+template <typename Class, typename FuncT, FuncT fn, typename arg1_conv, typename arg2_conv> struct fn_wrapper_2a_v
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_arg1_type = typename arg1_conv::arg_type;
+    using conv_arg2_type = typename arg2_conv::arg_type;
+
+    static void wrapped_fn(class_type &cls, conv_arg1_type arg1, conv_arg2_type arg2)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        return (base.*fn)(arg1_conv()(ctx, arg1), arg2_conv()(ctx, arg2));
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+};
+
+// Three parameters, one return
+template <typename Class, typename FuncT, FuncT fn, typename arg1_conv, typename arg2_conv, typename arg3_conv>
+struct fn_wrapper_3a_v
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_arg1_type = typename arg1_conv::arg_type;
+    using conv_arg2_type = typename arg2_conv::arg_type;
+    using conv_arg3_type = typename arg3_conv::arg_type;
+
+    static void wrapped_fn(class_type &cls, conv_arg1_type arg1, conv_arg2_type arg2, conv_arg3_type arg3)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        return (base.*fn)(arg1_conv()(ctx, arg1), arg2_conv()(ctx, arg2), arg3_conv()(ctx, arg3));
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+};
+
+// Wrapped getter
+template <typename Class, typename MemT, MemT mem, typename v_conv> struct readonly_wrapper
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_val_type = typename v_conv::ret_type;
+
+    static object wrapped_getter(class_type &cls)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        try {
+            return object(v_conv()(ctx, (base.*mem)));
+        } catch (bad_wrap &) {
+            return object();
+        }
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name)
+    {
+        cls_.add_property(name, wrapped_getter);
+    }
+};
+
+// Wrapped getter/setter
+template <typename Class, typename MemT, MemT mem, typename get_conv, typename set_conv> struct readwrite_wrapper
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_val_type = typename get_conv::ret_type;
+
+    static object wrapped_getter(class_type &cls)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        try {
+            return object(get_conv()(ctx, (base.*mem)));
+        } catch (bad_wrap &) {
+            return object();
+        }
+    }
+
+    using conv_arg_type = typename set_conv::arg_type;
+
+    static void wrapped_setter(class_type &cls, conv_arg_type val)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        (base.*mem) = set_conv()(ctx, val);
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name)
+    {
+        cls_.add_property(name, wrapped_getter, wrapped_setter);
     }
 };