19 files changed, 1370 insertions, 0 deletions

diff --git a/extra/guile/CMakeLists.txt b/extra/guile/CMakeLists.txt
new file mode 100644
index 000000000000..99338060d6da
--- /dev/null
+++ b/extra/guile/CMakeLists.txt
@@ -0,0 +1,24 @@
+
+find_package(PkgConfig)
+
+pkg_check_modules(Guile guile-2.2)
+
+if (NOT Guile_FOUND)
+  message(STATUS "Disabling Guile modules")
+  return()
+endif()
+
+set(GUILE_EXTENSION_DIR ${CMAKE_CURRENT_BINARY_DIR})
+configure_file(immer.scm.in immer.scm)
+
+add_library(guile-immer SHARED EXCLUDE_FROM_ALL
+  src/immer.cpp)
+target_include_directories(guile-immer PUBLIC
+  ${CMAKE_CURRENT_SOURCE_DIR}
+  ${CALLABLE_TRAITS_INCLUDE_DIR}
+  ${Guile_INCLUDE_DIRS})
+target_link_libraries(guile-immer PUBLIC
+  immer
+  ${Guile_LIBRARIES})
+
+add_custom_target(guile DEPENDS guile-immer)
diff --git a/extra/guile/README.rst b/extra/guile/README.rst
new file mode 100644
index 000000000000..09cf8be644ec
--- /dev/null
+++ b/extra/guile/README.rst
@@ -0,0 +1,144 @@
+
+Guile bindings
+==============
+
+This library includes experimental bindings bring efficient immutable
+vectors for the `GNU Guile`_ Scheme implementation.  The interface is
+somewhat **incomplete**, but you can already do something interesting
+things like:
+
+.. literalinclude:: ../extra/guile/example.scm
+   :language: scheme
+   :start-after: intro/start
+   :end-before:  intro/end
+..
+
+    **Do you want to help** making these bindings complete and production
+    ready?  Drop a line at `immer@sinusoid.al
+    <mailto:immer@sinusoid.al>`_ or `open an issue on Github
+    <https://github.com/arximboldi/immer>`_
+
+.. _GNU Guile: https://www.gnu.org/software/guile/
+
+Installation
+------------
+
+.. highlight:: sh
+
+To install the software, you need `GNU Guile 2.2
+<https://www.gnu.org/software/guile/download/>`_.  Then you have to
+`clone the repository <https://github.com/arximboldi/immer>`_ and
+inside the repository do something like::
+
+    mkdir build; cd build
+    cmake .. -DCMAKE_BUILD_TYPE=Release \
+             -DGUILE_EXTENSION_DIR="<somewhere...>"
+    make guile
+    cp extra/guile/libguile-immer.so "<...the GUILE_EXTENSION_DIR>"
+    cp extra/guile/immer.scm "<somewhere in your GUILE_LOAD_PATH>"
+
+Benchmarks
+----------
+
+The library includes some quick and dirty benchmarks that show how
+these vectors perform compared to *mutable vectors*, *lists*, and
+*v-lists*.  Once you have installed the library, you may run them by
+executing the following in the project root::
+
+    guile extra/guile/benchmark.scm
+
+This is the output I get when running those:
+
+.. code-block:: scheme
+   :name: benchmark-output
+
+   (define bench-size 1000000)
+   (define bench-samples 10)
+   ;;;; benchmarking creation...
+   ; evaluating:
+         (apply ivector (iota bench-size))
+   ; average time: 0.0608697784 seconds
+   ; evaluating:
+         (apply ivector-u32 (iota bench-size))
+   ; average time: 0.0567354933 seconds
+   ; evaluating:
+         (iota bench-size)
+   ; average time: 0.032995402 seconds
+   ; evaluating:
+         (apply vector (iota bench-size))
+   ; average time: 0.0513594425 seconds
+   ; evaluating:
+         (apply u32vector (iota bench-size))
+   ; average time: 0.0939185315 seconds
+   ; evaluating:
+         (list->vlist (iota bench-size))
+   ; average time: 0.2369570977 seconds
+   ;;;; benchmarking iteration...
+   (define bench-ivector (apply ivector (iota bench-size)))
+   (define bench-ivector-u32 (apply ivector-u32 (iota bench-size)))
+   (define bench-list (iota bench-size))
+   (define bench-vector (apply vector (iota bench-size)))
+   (define bench-u32vector (apply u32vector (iota bench-size)))
+   (define bench-vlist (list->vlist (iota bench-size)))
+   ; evaluating:
+         (ivector-fold + 0 bench-ivector)
+   ; average time: 0.035750341 seconds
+   ; evaluating:
+         (ivector-u32-fold + 0 bench-ivector-u32)
+   ; average time: 0.0363843682 seconds
+   ; evaluating:
+         (fold + 0 bench-list)
+   ; average time: 0.0271881423 seconds
+   ; evaluating:
+         (vector-fold + 0 bench-vector)
+   ; average time: 0.0405022349 seconds
+   ; evaluating:
+         (vlist-fold + 0 bench-vlist)
+   ; average time: 0.0424709098 seconds
+   ;;;; benchmarking iteration by index...
+   ; evaluating:
+         (let iter ((i 0) (acc 0))
+           (if (< i (ivector-length bench-ivector))
+             (iter (+ i 1) (+ acc (ivector-ref bench-ivector i)))
+             acc))
+   ; average time: 0.2195658936 seconds
+   ; evaluating:
+         (let iter ((i 0) (acc 0))
+           (if (< i (ivector-u32-length bench-ivector-u32))
+             (iter (+ i 1) (+ acc (ivector-u32-ref bench-ivector-u32 i)))
+             acc))
+   ; average time: 0.2205486326 seconds
+   ; evaluating:
+         (let iter ((i 0) (acc 0))
+           (if (< i (vector-length bench-vector))
+             (iter (+ i 1) (+ acc (vector-ref bench-vector i)))
+             acc))
+   ; average time: 0.0097157637 seconds
+   ; evaluating:
+         (let iter ((i 0) (acc 0))
+           (if (< i (u32vector-length bench-u32vector))
+             (iter (+ i 1) (+ acc (u32vector-ref bench-u32vector i)))
+             acc))
+   ; average time: 0.0733736008 seconds
+   ; evaluating:
+         (let iter ((i 0) (acc 0))
+           (if (< i (vlist-length bench-vlist))
+             (iter (+ i 1) (+ acc (vlist-ref bench-vlist i)))
+             acc))
+   ; average time: 0.3220357243 seconds
+   ;;;; benchmarking concatenation...
+   ; evaluating:
+         (ivector-append bench-ivector bench-ivector)
+   ; average time: 1.63022e-5 seconds
+   ; evaluating:
+         (ivector-u32-append bench-ivector-u32 bench-ivector-u32)
+   ; average time: 1.63754e-5 seconds
+   ; evaluating:
+         (append bench-list bench-list)
+   ; average time: 0.0135592963 seconds
+   ; evaluating:
+         (vector-append bench-vector bench-vector)
+   ; average time: 0.0044506586 seconds
+   ; evaluating:
+         (vlist-append bench-vlist bench-vlist)
+   ; average time: 0.3227312512 seconds
diff --git a/extra/guile/benchmark.scm b/extra/guile/benchmark.scm
new file mode 100644
index 000000000000..463a8eb17d9e
--- /dev/null
+++ b/extra/guile/benchmark.scm
@@ -0,0 +1,168 @@
+;;
+;; immer: immutable data structures for C++
+;; Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+;;
+;; This software is distributed under the Boost Software License, Version 1.0.
+;; See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+;;
+
+(use-modules (immer)
+             (fector) ; https://wingolog.org/pub/fector.scm
+             (srfi srfi-1)
+             (srfi srfi-43)
+             (ice-9 vlist)
+             (ice-9 pretty-print)
+             (rnrs bytevectors))
+
+(define-syntax display-eval
+  (syntax-rules ()
+    ((_ expr)
+     (begin (pretty-print 'expr
+                          #:max-expr-width 72)
+            expr))))
+
+(display-eval (define bench-size 1000000))
+(display-eval (define bench-samples 10))
+
+(define (average . ns)
+  (/ (apply + ns) (length ns)))
+
+(define (generate-n n fn)
+  (unfold (lambda (x) (= x n))
+          (lambda (x) (fn))
+          (lambda (x) (+ x 1))
+          0))
+
+(define-syntax benchmark
+  (syntax-rules ()
+    ((_ expr)
+     (begin
+       (display "; evaluating:    ") (newline)
+       (pretty-print 'expr
+                     #:max-expr-width 72
+                     #:per-line-prefix "      ")
+       (let* ((sample (lambda ()
+                        (gc)
+                        (let* ((t0 (get-internal-real-time))
+                               (r  expr)
+                               (t1 (get-internal-real-time)))
+                          (/ (- t1 t0) internal-time-units-per-second))))
+              (samples (generate-n bench-samples sample))
+              (result (apply average samples)))
+         (display "; average time: ")
+         (display (exact->inexact result))
+         (display " seconds")
+         (newline))))))
+
+(display ";;;; benchmarking creation...") (newline)
+
+(display-eval
+ (define (fector . args)
+   (persistent-fector (fold (lambda (v fv) (fector-push! fv v))
+                            (transient-fector)
+                            args))))
+
+(benchmark (apply ivector (iota bench-size)))
+(benchmark (apply ivector-u32 (iota bench-size)))
+(benchmark (iota bench-size))
+(benchmark (apply vector (iota bench-size)))
+(benchmark (apply u32vector (iota bench-size)))
+(benchmark (list->vlist (iota bench-size)))
+(benchmark (apply fector (iota bench-size)))
+
+(display ";;;; benchmarking iteration...") (newline)
+
+(display-eval (define bench-ivector (apply ivector (iota bench-size))))
+(display-eval (define bench-ivector-u32 (apply ivector-u32 (iota bench-size))))
+(display-eval (define bench-list (iota bench-size)))
+(display-eval (define bench-vector (apply vector (iota bench-size))))
+(display-eval (define bench-u32vector (apply u32vector (iota bench-size))))
+(display-eval (define bench-vlist (list->vlist (iota bench-size))))
+(display-eval (define bench-fector (apply fector (iota bench-size))))
+(display-eval (define bench-bytevector-u32
+                (uint-list->bytevector (iota bench-size)
+                                       (native-endianness)
+                                       4)))
+
+(benchmark (ivector-fold + 0 bench-ivector))
+(benchmark (ivector-u32-fold + 0 bench-ivector-u32))
+(benchmark (fold + 0 bench-list))
+(benchmark (vector-fold + 0 bench-vector))
+(benchmark (vlist-fold + 0 bench-vlist))
+(benchmark (fector-fold + bench-fector 0))
+
+(display ";;;; benchmarking iteration by index...") (newline)
+
+(display-eval
+ (define-syntax iteration-by-index
+   (syntax-rules ()
+     ((_ *length *ref *vector *step)
+      (let ((len (*length *vector)))
+        (let iter ((i 0) (acc 0))
+          (if (< i len)
+              (iter (+ i *step)
+                    (+ acc (*ref *vector i)))
+              acc)))))))
+
+(display-eval
+ (define-syntax iteration-by-index-truncate
+   (syntax-rules ()
+     ((_ *length *ref *vector *step)
+      (let ((len (*length *vector)))
+        (let iter ((i 0) (acc 0))
+          (if (< i len)
+              (iter (+ i *step)
+                    (logand #xffffffffFFFFFFFF
+                            (+ acc (*ref *vector i))))
+              acc)))))))
+
+(benchmark (iteration-by-index ivector-length
+                               ivector-ref
+                               bench-ivector 1))
+(benchmark (iteration-by-index ivector-u32-length
+                               ivector-u32-ref
+                               bench-ivector-u32 1))
+(benchmark (iteration-by-index vector-length
+                               vector-ref
+                               bench-vector 1))
+(benchmark (iteration-by-index u32vector-length
+                               u32vector-ref
+                               bench-u32vector 1))
+(benchmark (iteration-by-index vlist-length
+                               vlist-ref
+                               bench-vlist 1))
+(benchmark (iteration-by-index fector-length
+                               fector-ref
+                               bench-fector 1))
+(benchmark (iteration-by-index bytevector-length
+                               bytevector-u32-native-ref
+                               bench-bytevector-u32 4))
+
+(benchmark (iteration-by-index-truncate ivector-length
+                                        ivector-ref
+                                        bench-ivector 1))
+(benchmark (iteration-by-index-truncate ivector-u32-length
+                                        ivector-u32-ref
+                                        bench-ivector-u32 1))
+(benchmark (iteration-by-index-truncate vector-length
+                                        vector-ref
+                                        bench-vector 1))
+(benchmark (iteration-by-index-truncate u32vector-length
+                                        u32vector-ref
+                                        bench-u32vector 1))
+(benchmark (iteration-by-index-truncate vlist-length
+                                        vlist-ref
+                                        bench-vlist 1))
+(benchmark (iteration-by-index-truncate fector-length
+                                        fector-ref
+                                        bench-fector 1))
+(benchmark (iteration-by-index-truncate bytevector-length
+                                        bytevector-u32-native-ref
+                                        bench-bytevector-u32 4))
+
+(display ";;;; benchmarking concatenation...") (newline)
+(benchmark (ivector-append bench-ivector bench-ivector))
+(benchmark (ivector-u32-append bench-ivector-u32 bench-ivector-u32))
+(benchmark (append bench-list bench-list))
+(benchmark (vector-append bench-vector bench-vector))
+(benchmark (vlist-append bench-vlist bench-vlist))
diff --git a/extra/guile/example.scm b/extra/guile/example.scm
new file mode 100644
index 000000000000..6649508cedc3
--- /dev/null
+++ b/extra/guile/example.scm
@@ -0,0 +1,51 @@
+;;
+;; immer: immutable data structures for C++
+;; Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+;;
+;; This software is distributed under the Boost Software License, Version 1.0.
+;; See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+;;
+
+;; include:intro/start
+(use-modules (immer)
+             (rnrs base))
+
+(let ((v1 (ivector 1 "hola" 3 'que #:tal)))
+  (assert (eq? (ivector-ref v1 3) 'que))
+
+  (let* ((v2 (ivector-set v1 3 'what))
+         (v2 (ivector-update v2 2 (lambda (x) (+ 1 x)))))
+    (assert (eq? (ivector-ref v1 2) 3))
+    (assert (eq? (ivector-ref v1 3) 'que))
+    (assert (eq? (ivector-ref v2 2) 4))
+    (assert (eq? (ivector-ref v2 3) 'what))
+
+    (let ((v3 (ivector-push v2 "hehe")))
+      (assert (eq? (ivector-length v3) 6))
+      (assert (eq? (ivector-ref v3 (- (ivector-length v3) 1)) "hehe")))))
+
+(let ((v (apply ivector (iota 10))))
+  (assert (eq? (ivector-length v) 10))
+  (assert (eq? (ivector-length (ivector-drop v 3)) 7))
+  (assert (eq? (ivector-length (ivector-take v 3)) 3))
+  (assert (eq? (ivector-length (ivector-append v v)) 20)))
+
+(let ((v1 (make-ivector 3))
+      (v2 (make-ivector 3 ":)")))
+  (assert (eq? (ivector-ref v1 2)
+               (vector-ref (make-vector 3) 2)))
+  (assert (eq? (ivector-ref v2 2) ":)")))
+;; include:intro/end
+
+;; Experiments
+
+(let ((d (dummy)))
+  (dummy-foo d)
+  (dummy-bar d 42))
+(gc)
+
+(func1)
+(func2)
+(func3 (dummy) 12)
+(foo-func1)
+(gc)
diff --git a/extra/guile/immer.scm.in b/extra/guile/immer.scm.in
new file mode 100644
index 000000000000..8624aabd5bf4
--- /dev/null
+++ b/extra/guile/immer.scm.in
@@ -0,0 +1,5 @@
+(define-module (immer))
+
+;; The extension automatically exports the names via 'scm_c_export'
+(load-extension "@GUILE_EXTENSION_DIR@/libguile-immer"
+                "init_immer")
diff --git a/extra/guile/scm/detail/convert.hpp b/extra/guile/scm/detail/convert.hpp
new file mode 100644
index 000000000000..4c87ff185669
--- /dev/null
+++ b/extra/guile/scm/detail/convert.hpp
@@ -0,0 +1,58 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#pragma once
+
+#include <scm/detail/util.hpp>
+
+#include <cstdint>
+#include <type_traits>
+#include <utility>
+
+#include <libguile.h>
+
+namespace scm {
+namespace detail {
+
+template <typename T, typename Enable=void>
+struct convert;
+
+template <typename T>
+auto to_scm(T&& v)
+    -> SCM_DECLTYPE_RETURN(
+        convert<std::decay_t<T>>::to_scm(std::forward<T>(v)));
+
+template <typename T>
+auto to_cpp(SCM v)
+    -> SCM_DECLTYPE_RETURN(
+        convert<std::decay_t<T>>::to_cpp(v));
+
+} // namespace detail
+} // namespace scm
+
+#define SCM_DECLARE_NUMERIC_TYPE(cpp_name__, scm_name__)                \
+    namespace scm {                                                     \
+    namespace detail {                                                  \
+    template <>                                                         \
+    struct convert<cpp_name__> {                                        \
+        static cpp_name__ to_cpp(SCM v) { return scm_to_ ## scm_name__(v); } \
+        static SCM to_scm(cpp_name__ v) { return scm_from_ ## scm_name__(v); } \
+    };                                                                  \
+    }} /* namespace scm::detail */                                      \
+    /**/
+
+SCM_DECLARE_NUMERIC_TYPE(float,         double);
+SCM_DECLARE_NUMERIC_TYPE(double,        double);
+SCM_DECLARE_NUMERIC_TYPE(std::int8_t,   int8);
+SCM_DECLARE_NUMERIC_TYPE(std::int16_t,  int16);
+SCM_DECLARE_NUMERIC_TYPE(std::int32_t,  int32);
+SCM_DECLARE_NUMERIC_TYPE(std::int64_t,  int64);
+SCM_DECLARE_NUMERIC_TYPE(std::uint8_t,  uint8);
+SCM_DECLARE_NUMERIC_TYPE(std::uint16_t, uint16);
+SCM_DECLARE_NUMERIC_TYPE(std::uint32_t, uint32);
+SCM_DECLARE_NUMERIC_TYPE(std::uint64_t, uint64);
diff --git a/extra/guile/scm/detail/define.hpp b/extra/guile/scm/detail/define.hpp
new file mode 100644
index 000000000000..08b6e763381f
--- /dev/null
+++ b/extra/guile/scm/detail/define.hpp
@@ -0,0 +1,36 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#pragma once
+
+#ifndef SCM_AUTO_EXPORT
+#define SCM_AUTO_EXPORT 1
+#endif
+
+#include <scm/detail/subr_wrapper.hpp>
+#include <scm/list.hpp>
+
+namespace scm {
+namespace detail {
+
+template <typename Tag, typename Fn>
+static void define_impl(const std::string& name, Fn fn)
+{
+    using args_t = function_args_t<Fn>;
+    constexpr auto args_size = pack_size_v<args_t>;
+    constexpr auto has_rest  = std::is_same<pack_last_t<args_t>, scm::args>{};
+    constexpr auto arg_count = args_size - has_rest;
+    auto subr = (scm_t_subr) +subr_wrapper_aux<Tag>(fn, args_t{});
+    scm_c_define_gsubr(name.c_str(), arg_count, 0, has_rest, subr);
+#if SCM_AUTO_EXPORT
+    scm_c_export(name.c_str());
+#endif
+}
+
+} // namespace detail
+} // namespace scm
diff --git a/extra/guile/scm/detail/finalizer_wrapper.hpp b/extra/guile/scm/detail/finalizer_wrapper.hpp
new file mode 100644
index 000000000000..258249eb2c73
--- /dev/null
+++ b/extra/guile/scm/detail/finalizer_wrapper.hpp
@@ -0,0 +1,62 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#pragma once
+
+#include <scm/detail/invoke.hpp>
+#include <scm/detail/function_args.hpp>
+#include <scm/detail/convert.hpp>
+
+namespace scm {
+namespace detail {
+// this anonymous namespace should help avoiding registration clashes
+// among translation units.
+namespace {
+
+template <typename Tag, typename Fn>
+auto finalizer_wrapper_impl(Fn fn, pack<>)
+{
+    check_call_once<Tag, Fn>();
+    static const Fn fn_ = fn;
+    return [] { invoke(fn_); };
+}
+template <typename Tag, typename Fn, typename T1>
+auto finalizer_wrapper_impl(Fn fn, pack<T1>)
+{
+    check_call_once<Tag, Fn>();
+    static const Fn fn_ = fn;
+    return [] (SCM a1) { invoke(fn_, to_cpp<T1>(a1)); };
+}
+template <typename Tag, typename Fn, typename T1, typename T2>
+auto finalizer_wrapper_impl(Fn fn, pack<T1, T2>)
+{
+    check_call_once<Tag, Fn>();
+    static const Fn fn_ = fn;
+    return [] (SCM a1, SCM a2) {
+        invoke(fn_, to_cpp<T1>(a1), to_cpp<T2>(a2));
+    };
+}
+template <typename Tag, typename Fn, typename T1, typename T2, typename T3>
+auto finalizer_wrapper_impl(Fn fn, pack<T1, T2, T3>)
+{
+    check_call_once<Tag, Fn>();
+    static const Fn fn_ = fn;
+    return [] (SCM a1, SCM a2, SCM a3) {
+        invoke(fn_, to_cpp<T1>(a1), to_cpp<T2>(a2), to_cpp<T3>(a3));
+    };
+}
+
+template <typename Tag, typename Fn>
+auto finalizer_wrapper(Fn fn)
+{
+    return finalizer_wrapper_impl<Tag>(fn, function_args_t<Fn>{});
+}
+
+} // anonymous namespace
+} // namespace detail
+} // namespace scm
diff --git a/extra/guile/scm/detail/function_args.hpp b/extra/guile/scm/detail/function_args.hpp
new file mode 100644
index 000000000000..809e3eb1979b
--- /dev/null
+++ b/extra/guile/scm/detail/function_args.hpp
@@ -0,0 +1,21 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#pragma once
+
+#include <scm/detail/pack.hpp>
+#include <boost/callable_traits/args.hpp>
+
+namespace scm {
+namespace detail {
+
+template <typename Fn>
+using function_args_t = boost::callable_traits::args_t<Fn, pack>;
+
+} // namespace detail
+} // namespace scm
diff --git a/extra/guile/scm/detail/invoke.hpp b/extra/guile/scm/detail/invoke.hpp
new file mode 100644
index 000000000000..d9f2b37ccece
--- /dev/null
+++ b/extra/guile/scm/detail/invoke.hpp
@@ -0,0 +1,39 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#pragma once
+
+// Adapted from the official std::invoke proposal:
+// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4169.html
+
+#include <type_traits>
+#include <functional>
+
+namespace scm {
+namespace detail {
+
+template <typename Functor, typename... Args>
+std::enable_if_t<
+    std::is_member_pointer<std::decay_t<Functor>>::value,
+    std::result_of_t<Functor&&(Args&&...)>>
+invoke(Functor&& f, Args&&... args)
+{
+    return std::mem_fn(f)(std::forward<Args>(args)...);
+}
+
+template <typename Functor, typename... Args>
+std::enable_if_t<
+    !std::is_member_pointer<std::decay_t<Functor>>::value,
+    std::result_of_t<Functor&&(Args&&...)>>
+invoke(Functor&& f, Args&&... args)
+{
+    return std::forward<Functor>(f)(std::forward<Args>(args)...);
+}
+
+} // namespace detail
+} // namespace scm
diff --git a/extra/guile/scm/detail/pack.hpp b/extra/guile/scm/detail/pack.hpp
new file mode 100644
index 000000000000..9a1813570bcd
--- /dev/null
+++ b/extra/guile/scm/detail/pack.hpp
@@ -0,0 +1,52 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#pragma once
+
+namespace scm {
+namespace detail {
+
+struct none_t;
+
+template <typename... Ts>
+struct pack {};
+
+template <typename Pack>
+struct pack_size;
+
+template <typename... Ts>
+struct pack_size<pack<Ts...>>
+{
+    static constexpr auto value = sizeof...(Ts);
+};
+
+template <typename Pack>
+constexpr auto pack_size_v = pack_size<Pack>::value;
+
+template <typename Pack>
+struct pack_last
+{
+    using type = none_t;
+};
+
+template <typename T, typename ...Ts>
+struct pack_last<pack<T, Ts...>>
+    : pack_last<pack<Ts...>>
+{};
+
+template <typename T>
+struct pack_last<pack<T>>
+{
+    using type = T;
+};
+
+template <typename Pack>
+using pack_last_t = typename pack_last<Pack>::type;
+
+} // namespace detail
+} // namespace scm
diff --git a/extra/guile/scm/detail/subr_wrapper.hpp b/extra/guile/scm/detail/subr_wrapper.hpp
new file mode 100644
index 000000000000..fc11ff1c51ec
--- /dev/null
+++ b/extra/guile/scm/detail/subr_wrapper.hpp
@@ -0,0 +1,111 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#pragma once
+
+#include <scm/detail/invoke.hpp>
+#include <scm/detail/function_args.hpp>
+#include <scm/detail/convert.hpp>
+
+namespace scm {
+namespace detail {
+
+// this anonymous namespace should help avoiding registration clashes
+// among translation units.
+namespace {
+
+template <typename Tag, typename R, typename Fn>
+auto subr_wrapper_impl(Fn fn, pack<R>, pack<>)
+{
+    check_call_once<Tag, Fn>();
+    static const Fn fn_ = fn;
+    return [] () -> SCM { return to_scm(invoke(fn_)); };
+}
+template <typename Tag, typename Fn, typename R, typename T1>
+auto subr_wrapper_impl(Fn fn, pack<R>, pack<T1>)
+{
+    check_call_once<Tag, Fn>();
+    static const Fn fn_ = fn;
+    return [] (SCM a1) -> SCM {
+        return to_scm(invoke(fn_, to_cpp<T1>(a1)));
+    };
+}
+template <typename Tag, typename Fn, typename R, typename T1, typename T2>
+auto subr_wrapper_impl(Fn fn, pack<R>, pack<T1, T2>)
+{
+    check_call_once<Tag, Fn>();
+    static const Fn fn_ = fn;
+    return [] (SCM a1, SCM a2) -> SCM {
+        return to_scm(invoke(fn_, to_cpp<T1>(a1), to_cpp<T2>(a2)));
+    };
+}
+template <typename Tag, typename Fn, typename R, typename T1, typename T2,
+          typename T3>
+auto subr_wrapper_impl(Fn fn, pack<R>, pack<T1, T2, T3>)
+{
+    check_call_once<Tag, Fn>();
+    static const Fn fn_ = fn;
+    return [] (SCM a1, SCM a2, SCM a3) -> SCM {
+        return to_scm(invoke(fn_, to_cpp<T1>(a1), to_cpp<T2>(a2),
+                             to_cpp<T3>(a3)));
+    };
+}
+
+template <typename Tag, typename Fn>
+auto subr_wrapper_impl(Fn fn, pack<void>, pack<>)
+{
+    check_call_once<Tag, Fn>();
+    static const Fn fn_ = fn;
+    return [] () -> SCM { invoke(fn_); return SCM_UNSPECIFIED; };
+}
+template <typename Tag, typename Fn, typename T1>
+auto subr_wrapper_impl(Fn fn, pack<void>, pack<T1>)
+{
+    check_call_once<Tag, Fn>();
+    static const Fn fn_ = fn;
+    return [] (SCM a1) -> SCM {
+        invoke(fn_, to_cpp<T1>(a1)); return SCM_UNSPECIFIED;
+    };
+}
+template <typename Tag, typename Fn, typename T1, typename T2>
+auto subr_wrapper_impl(Fn fn, pack<void>, pack<T1, T2>)
+{
+    check_call_once<Tag, Fn>();
+    static const Fn fn_ = fn;
+    return [] (SCM a1, SCM a2) -> SCM {
+        invoke(fn_, to_cpp<T1>(a1), to_cpp<T2>(a2));
+        return SCM_UNSPECIFIED;
+    };
+}
+template <typename Tag, typename Fn, typename T1, typename T2, typename T3>
+auto subr_wrapper_impl(Fn fn, pack<void>, pack<T1, T2, T3>)
+{
+    check_call_once<Tag, Fn>();
+    static const Fn fn_ = fn;
+    return [] (SCM a1, SCM a2, SCM a3) -> SCM {
+        invoke(fn_, to_cpp<T1>(a1), to_cpp<T2>(a2), to_cpp<T3>(a3));
+        return SCM_UNSPECIFIED;
+    };
+}
+
+template <typename Tag, typename Fn, typename... Args>
+auto subr_wrapper_aux(Fn fn, pack<Args...>)
+{
+    return subr_wrapper_impl<Tag>(
+        fn, pack<std::result_of_t<Fn(Args...)>>{}, pack<Args...>{});
+}
+
+template <typename Tag, typename Fn>
+auto subr_wrapper(Fn fn)
+{
+    return subr_wrapper_aux<Tag>(fn, function_args_t<Fn>{});
+}
+
+} // anonymous namespace
+} // namespace detail
+} // namespace scm
diff --git a/extra/guile/scm/detail/util.hpp b/extra/guile/scm/detail/util.hpp
new file mode 100644
index 000000000000..fdc323722e99
--- /dev/null
+++ b/extra/guile/scm/detail/util.hpp
@@ -0,0 +1,49 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#pragma once
+
+#include <libguile.h>
+
+namespace scm {
+namespace detail {
+
+#define SCM_DECLTYPE_RETURN(...)                \
+    decltype(__VA_ARGS__)                       \
+    { return __VA_ARGS__; }                     \
+    /**/
+
+template <typename... Ts>
+constexpr bool is_valid_v = true;
+
+template <typename... Ts>
+using is_valid_t = void;
+
+template <typename... Ts>
+void check_call_once()
+{
+    static bool called = false;
+    if (called) scm_misc_error (nullptr, "Double defined binding. \
+This may be caused because there are multiple C++ binding groups in the same \
+translation unit.  You may solve this by using different type tags for each \
+binding group.", SCM_EOL);
+    called = true;
+}
+
+struct move_sequence
+{
+    move_sequence() = default;
+    move_sequence(const move_sequence&) = delete;
+    move_sequence(move_sequence&& other)
+    { other.moved_from_ = true; };
+
+    bool moved_from_ = false;
+};
+
+} // namespace detail
+} // namespace scm
diff --git a/extra/guile/scm/group.hpp b/extra/guile/scm/group.hpp
new file mode 100644
index 000000000000..69cd385820cb
--- /dev/null
+++ b/extra/guile/scm/group.hpp
@@ -0,0 +1,88 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#pragma once
+
+#include <scm/detail/define.hpp>
+#include <string>
+
+namespace scm {
+namespace detail {
+
+template <typename Tag, int Seq=0>
+struct definer
+{
+    using this_t = definer;
+    using next_t = definer<Tag, Seq + 1>;
+
+    std::string group_name_ = {};
+
+    definer() = default;
+    definer(definer&&) = default;
+
+    template <int Seq2,
+              typename Enable=std::enable_if_t<Seq2 + 1 == Seq>>
+    definer(definer<Tag, Seq2>)
+    {}
+
+    template <typename Fn>
+    next_t define(std::string name, Fn fn) &&
+    {
+        define_impl<this_t>(name, fn);
+        return { std::move(*this) };
+    }
+
+    template <typename Fn>
+    next_t maker(Fn fn) &&
+    {
+        define_impl<this_t>("make", fn);
+        return { std::move(*this) };
+    }
+};
+
+template <typename Tag, int Seq=0>
+struct group_definer
+{
+    using this_t = group_definer;
+    using next_t = group_definer<Tag, Seq + 1>;
+
+    std::string group_name_ = {};
+
+    group_definer(std::string name)
+        : group_name_{std::move(name)} {}
+
+    group_definer(group_definer&&) = default;
+
+    template <int Seq2,
+              typename Enable=std::enable_if_t<Seq2 + 1 == Seq>>
+    group_definer(group_definer<Tag, Seq2>)
+    {}
+
+    template <typename Fn>
+    next_t define(std::string name, Fn fn) &&
+    {
+        define_impl<this_t>(group_name_ + "-" + name, fn);
+        return { std::move(*this) };
+    }
+};
+
+} // namespace detail
+
+template <typename Tag=void>
+detail::definer<Tag> group()
+{
+    return {};
+}
+
+template <typename Tag=void>
+detail::group_definer<Tag> group(std::string name)
+{
+    return { std::move(name) };
+}
+
+} // namespace scm
diff --git a/extra/guile/scm/list.hpp b/extra/guile/scm/list.hpp
new file mode 100644
index 000000000000..dc162c200244
--- /dev/null
+++ b/extra/guile/scm/list.hpp
@@ -0,0 +1,54 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#pragma once
+
+#include <scm/val.hpp>
+#include <iostream>
+
+namespace scm {
+
+struct list : detail::wrapper
+{
+    using base_t = detail::wrapper;
+    using base_t::base_t;
+
+    using iterator = list;
+    using value_type = val;
+
+    list() : base_t{SCM_EOL} {};
+    list end() const { return {}; }
+    list begin() const { return *this; }
+
+    explicit operator bool() { return handle_ != SCM_EOL; }
+
+    val operator* () const { return val{scm_car(handle_)}; }
+
+    list& operator++ ()
+    {
+        handle_ = scm_cdr(handle_);
+        return *this;
+    }
+
+    list operator++ (int)
+    {
+        auto result = *this;
+        result.handle_ = scm_cdr(handle_);
+        return result;
+    }
+};
+
+struct args : list
+{
+    using list::list;
+};
+
+} // namespace scm
+
+SCM_DECLARE_WRAPPER_TYPE(scm::list);
+SCM_DECLARE_WRAPPER_TYPE(scm::args);
diff --git a/extra/guile/scm/scm.hpp b/extra/guile/scm/scm.hpp
new file mode 100644
index 000000000000..f4e4989a44a9
--- /dev/null
+++ b/extra/guile/scm/scm.hpp
@@ -0,0 +1,14 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#pragma once
+
+#include <scm/val.hpp>
+#include <scm/list.hpp>
+#include <scm/group.hpp>
+#include <scm/type.hpp>
diff --git a/extra/guile/scm/type.hpp b/extra/guile/scm/type.hpp
new file mode 100644
index 000000000000..da53ed46ef8b
--- /dev/null
+++ b/extra/guile/scm/type.hpp
@@ -0,0 +1,153 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#pragma once
+
+#include <scm/detail/finalizer_wrapper.hpp>
+#include <scm/detail/define.hpp>
+#include <string>
+
+namespace scm {
+namespace detail {
+
+template <typename T>
+struct foreign_type_storage
+{
+    static SCM data;
+};
+
+template <typename T>
+SCM foreign_type_storage<T>::data = SCM_UNSPECIFIED;
+
+template <typename T>
+struct convert_foreign_type
+{
+    using storage_t = foreign_type_storage<T>;
+    static T& to_cpp(SCM v)
+    {
+        assert(storage_t::data != SCM_UNSPECIFIED &&
+               "can not convert to undefined type");
+        scm_assert_foreign_object_type(storage_t::data, v);
+        return *(T*)scm_foreign_object_ref(v, 0);
+    }
+
+    template <typename U>
+    static SCM to_scm(U&& v)
+    {
+        assert(storage_t::data != SCM_UNSPECIFIED &&
+               "can not convert from undefined type");
+        return scm_make_foreign_object_1(
+            storage_t::data,
+            new (scm_gc_malloc(sizeof(T), "scmpp")) T(
+                std::forward<U>(v)));
+    }
+};
+
+// Assume that every other type is foreign
+template <typename T>
+struct convert<T,
+               std::enable_if_t<!std::is_fundamental<T>::value &&
+                                // only value types are supported at
+                                // the moment but the story might
+                                // change later...
+                                !std::is_pointer<T>::value>>
+    : convert_foreign_type<T>
+{
+};
+
+template <typename Tag, typename T, int Seq=0>
+struct type_definer : move_sequence
+{
+    using this_t = type_definer;
+    using next_t = type_definer<Tag, T, Seq + 1>;
+
+    std::string type_name_ = {};
+    scm_t_struct_finalize finalizer_ = nullptr;
+
+    type_definer(type_definer&&) = default;
+
+    type_definer(std::string type_name)
+        : type_name_(std::move(type_name))
+    {}
+
+    ~type_definer()
+    {
+        if (!moved_from_) {
+            using storage_t = detail::foreign_type_storage<T>;
+            assert(storage_t::data == SCM_UNSPECIFIED);
+            storage_t::data = scm_make_foreign_object_type(
+                scm_from_utf8_symbol(("<" + type_name_ + ">").c_str()),
+                scm_list_1(scm_from_utf8_symbol("data")),
+                finalizer_);
+        }
+    }
+
+    template <int Seq2, typename Enable=std::enable_if_t<Seq2 + 1 == Seq>>
+    type_definer(type_definer<Tag, T, Seq2> r)
+        : move_sequence{std::move(r)}
+        , type_name_{std::move(r.type_name_)}
+        , finalizer_{std::move(r.finalizer_)}
+    {}
+
+    next_t constructor() &&
+    {
+        define_impl<this_t>(type_name_, [] { return T{}; });
+        return { std::move(*this) };
+    }
+
+    template <typename Fn>
+    next_t constructor(Fn fn) &&
+    {
+        define_impl<this_t>(type_name_, fn);
+        return { std::move(*this) };
+    }
+
+    next_t finalizer() &&
+    {
+        finalizer_ = (scm_t_struct_finalize) +finalizer_wrapper<Tag>(
+            [] (T& x) { x.~T(); });
+        return { std::move(*this) };
+    }
+
+    template <typename Fn>
+    next_t finalizer(Fn fn) &&
+    {
+        finalizer_ = (scm_t_struct_finalize) +finalizer_wrapper<Tag>(fn);
+        return { std::move(*this) };
+    }
+
+    next_t maker() &&
+    {
+        define_impl<this_t>("make-" + type_name_, [] { return T{}; });
+        return { std::move(*this) };
+    }
+
+    template <typename Fn>
+    next_t maker(Fn fn) &&
+    {
+        define_impl<this_t>("make-" + type_name_, fn);
+        return { std::move(*this) };
+    }
+
+    template <typename Fn>
+    next_t define(std::string name, Fn fn) &&
+    {
+        define_impl<this_t>(type_name_ + "-" + name, fn);
+        return { std::move(*this) };
+    }
+};
+
+} // namespace detail
+
+template <typename Tag, typename T=Tag>
+detail::type_definer<Tag, T> type(std::string type_name)
+{
+    return { type_name };
+}
+
+} // namespace scm
diff --git a/extra/guile/scm/val.hpp b/extra/guile/scm/val.hpp
new file mode 100644
index 000000000000..63d7189262da
--- /dev/null
+++ b/extra/guile/scm/val.hpp
@@ -0,0 +1,88 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#pragma once
+
+#include <scm/detail/convert.hpp>
+
+namespace scm {
+namespace detail {
+
+template <typename T>
+struct convert_wrapper_type
+{
+    static T to_cpp(SCM v) { return T{v}; }
+    static SCM to_scm(T v) { return v.get(); }
+};
+
+struct wrapper
+{
+    wrapper() = default;
+    wrapper(SCM hdl) : handle_{hdl} {}
+    SCM get() const { return handle_; }
+    operator SCM () const { return handle_; }
+
+    bool operator==(wrapper other) { return handle_ == other.handle_; }
+    bool operator!=(wrapper other) { return handle_ != other.handle_; }
+
+protected:
+    SCM handle_ = SCM_UNSPECIFIED;
+};
+
+} // namespace detail
+
+struct val : detail::wrapper
+{
+    using base_t = detail::wrapper;
+    using base_t::base_t;
+
+    template <typename T,
+              typename = std::enable_if_t<
+                  (!std::is_same<std::decay_t<T>, val>{} &&
+                   !std::is_same<std::decay_t<T>, SCM>{})>>
+    val(T&& x)
+        : base_t(detail::to_scm(std::forward<T>(x)))
+    {}
+
+    template <typename T,
+              typename = std::enable_if_t<
+                  std::is_same<T, decltype(detail::to_cpp<T>(SCM{}))>{}>>
+    operator T() const { return detail::to_cpp<T>(handle_); }
+
+    template <typename T,
+              typename = std::enable_if_t<
+                  std::is_same<T&, decltype(detail::to_cpp<T>(SCM{}))>{}>>
+    operator T& () const { return detail::to_cpp<T>(handle_); }
+
+    template <typename T,
+              typename = std::enable_if_t<
+                  std::is_same<const T&, decltype(detail::to_cpp<T>(SCM{}))>{}>>
+    operator const T& () const { return detail::to_cpp<T>(handle_); }
+
+    val operator() () const
+    { return val{scm_call_0(get())}; }
+    val operator() (val a0) const
+    { return val{scm_call_1(get(), a0)}; }
+    val operator() (val a0, val a1) const
+    { return val{scm_call_2(get(), a0, a1)}; }
+    val operator() (val a0, val a1, val a3) const
+    { return val{scm_call_3(get(), a0, a1, a3)}; }
+};
+
+} // namespace scm
+
+#define SCM_DECLARE_WRAPPER_TYPE(cpp_name__)                            \
+    namespace scm {                                                     \
+    namespace detail {                                                  \
+    template <>                                                         \
+    struct convert<cpp_name__>                                          \
+        : convert_wrapper_type<cpp_name__> {};                          \
+    }} /* namespace scm::detail */                                      \
+    /**/
+
+SCM_DECLARE_WRAPPER_TYPE(val);
diff --git a/extra/guile/src/immer.cpp b/extra/guile/src/immer.cpp
new file mode 100644
index 000000000000..7933447a8d18
--- /dev/null
+++ b/extra/guile/src/immer.cpp
@@ -0,0 +1,153 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#include <immer/flex_vector.hpp>
+#include <immer/flex_vector_transient.hpp>
+#include <immer/algorithm.hpp>
+#include <scm/scm.hpp>
+#include <iostream>
+
+namespace {
+
+struct guile_heap
+{
+    static void* allocate(std::size_t size)
+    { return scm_gc_malloc(size, "immer"); }
+
+    static void* allocate(std::size_t size, immer::norefs_tag)
+    { return scm_gc_malloc_pointerless(size, "immer"); }
+
+    template <typename ...Tags>
+    static void deallocate(std::size_t size, void* obj, Tags...)
+    { scm_gc_free(obj, size, "immer"); }
+};
+
+using guile_memory = immer::memory_policy<
+    immer::heap_policy<guile_heap>,
+    immer::no_refcount_policy,
+    immer::gc_transience_policy,
+    false>;
+
+template <typename T>
+using guile_ivector = immer::flex_vector<T, guile_memory>;
+
+struct dummy
+{
+    SCM port_ = scm_current_warning_port();
+
+    dummy(dummy&&)
+    { scm_puts("~~ dummy move constructor\n", port_); }
+
+    dummy()
+    { scm_puts("~~ dummy default constructor\n", port_); }
+
+    ~dummy()
+    { scm_puts("~~ dummy finalized\n", port_); }
+
+    void foo()
+    { scm_puts("~~ dummy foo\n", port_); }
+
+    int bar(int x)
+    {
+        auto res = x + 42;
+        scm_puts("~~ dummy bar: ", port_);
+        scm_display(scm::val{res}, port_);
+        scm_newline(port_);
+        return res;
+    }
+};
+
+template <int I>
+void func()
+{
+    auto port = scm_current_warning_port();
+    scm_puts("~~ func", port);
+    scm_display(scm_from_int(I), port);
+    scm_newline(port);
+}
+
+template <typename T = scm::val>
+void init_ivector(std::string type_name = "")
+{
+    using namespace std::string_literals;
+
+    using self_t = guile_ivector<T>;
+    using size_t = typename self_t::size_type;
+
+    auto name = "ivector"s + (type_name.empty() ? ""s : "-" + type_name);
+
+    scm::type<self_t>(name)
+        .constructor([] (scm::args rest) {
+            return self_t(rest.begin(), rest.end());
+        })
+        .maker([] (size_t n, scm::args rest) {
+            return self_t(n, rest ? *rest : scm::val{});
+        })
+        .define("ref", &self_t::operator[])
+        .define("length", &self_t::size)
+        .define("set", [] (const self_t& v, size_t i, scm::val x) {
+            return v.set(i, x);
+        })
+        .define("update", [] (const self_t& v, size_t i, scm::val fn) {
+            return v.update(i, fn);
+        })
+        .define("push", [] (const self_t& v, scm::val x) {
+            return v.push_back(x);
+        })
+        .define("take", [] (const self_t& v, size_t s) {
+            return v.take(s);
+        })
+        .define("drop", [] (const self_t& v, size_t s) {
+            return v.drop(s);
+        })
+        .define("append", [] (self_t v, scm::args rest) {
+            for (auto x : rest)
+                v = v + x;
+            return v;
+        })
+        .define("fold", [] (scm::val fn, scm::val first, const self_t& v) {
+            return immer::accumulate(v, first, fn);
+        })
+        ;
+}
+
+} // anonymous namespace
+
+struct bar_tag_t {};
+
+extern "C"
+void init_immer()
+{
+    scm::type<dummy>("dummy")
+        .constructor()
+        .finalizer()
+        .define("foo", &dummy::foo)
+        .define("bar", &dummy::bar);
+
+    scm::group()
+        .define("func1", func<1>);
+
+    scm::group<bar_tag_t>()
+        .define("func2", func<2>)
+        .define("func3", &dummy::bar);
+
+    scm::group("foo")
+        .define("func1", func<1>);
+
+    init_ivector();
+    init_ivector<std::uint8_t>("u8");
+    init_ivector<std::uint16_t>("u16");
+    init_ivector<std::uint32_t>("u32");
+    init_ivector<std::uint64_t>("u64");
+    init_ivector<std::int8_t>("s8");
+    init_ivector<std::int16_t>("s16");
+    init_ivector<std::int32_t>("s32");
+    init_ivector<std::int64_t>("s64");
+    init_ivector<float>("f32");
+    init_ivector<double>("f64");
+}