Hackery hackety hacks for PMFs

Author: vendethiel

src/cpp/bin/testml-cpp-tap

@@ -16,13 +16,14 @@ testml-run-file() {
   /usr/bin/env c++ \
     -o $testml_runner \
     -std=c++14 -Wall -Wextra \
-    -g \
+    -I ext \
     $src_bin \
     $lib/run/tap.cpp \
     $lib/runtime.cpp \
     $lib/stdlib.cpp \
     $lib/bridge.cpp \
     $lib/wrapper.cpp \
+    $lib/utils.cpp \
     $bridge_file || return
 
   chmod +x $testml_runner

src/cpp/lib/testml/bridge.hpp

@@ -7,8 +7,12 @@
 #include <stdexcept>
 #include <string>
 
-#include "../../ext/nlohmann/json.hpp"
+#include "boost/callable_traits/args.hpp"
+#include "boost/callable_traits/class_of.hpp"
+#include "boost/callable_traits/return_type.hpp"
+#include "nlohmann/json.hpp"
 
+#include "utils.hpp"
 #include "wrapper.hpp"
 
 namespace testml {
@@ -19,60 +23,85 @@ namespace testml {
     using wrapper::cook;
     using wrapper::uncook;
 
+    namespace ct = boost::callable_traits;
+
     // we need this details class so that we can have a non-templated value
     // stored in the Bridge _fns map.
     struct FnHolder {
       virtual json call(std::vector<json> const&) = 0;
     };
 
     // the implementation of a FnHolder, which keeps the types around
-    template<typename Ret, typename... Arg>
+    template<typename BridgeT, typename Fn>
     class FnHolderImpl : public FnHolder {
-      using Fn = std::function<Ret(Arg...)>;
       Fn _fn;
+      BridgeT* _bridge;
+      static constexpr bool _is_pmf = std::is_member_function_pointer<Fn>::value;
+      using RawArg = ct::args_t<Fn>;
+      // in case of a PMF, remove the class type from the argument list
+      using Arg = std::conditional_t<_is_pmf, typename utils::remove_first_type<RawArg>::type, RawArg>;
+      using Ret = ct::return_type_t<Fn>;
+      static constexpr std::size_t _num_args = std::tuple_size<Arg>::value;
 
       // type of the N-th argument that the stored function takes
       template<std::size_t I>
-      using ArgType = typename std::tuple_element<I, std::tuple<Arg...>>::type;
+      using ArgType = typename std::tuple_element<I, Arg>::type;
 
       // uncook each argument to its expected type, and call the function
+      // we do SFINAE in the return type, using comma+sizeof() to get a dependance on I.
+
+      // PMF case
+      template<std::size_t... I>
+      auto call_impl(std::vector<json> const& args, std::index_sequence<I...>)
+      -> typename std::enable_if<(sizeof...(I), _is_pmf), Ret>::type {
+        return (_bridge->*_fn)(uncook<ArgType<I>>(args[I])...);
+      }
+
+      // non-PMF case (BridgeT = nullptr_t)
       template<std::size_t... I>
-      Ret call_impl(std::vector<json> const& args, std::index_sequence<I...>) {
+      auto call_impl(std::vector<json> const& args, std::index_sequence<I...>)
+      -> typename std::enable_if<(sizeof...(I), !_is_pmf), Ret>::type {
         return _fn(uncook<ArgType<I>>(args[I])...);
       }
 
     public:
-      FnHolderImpl(Fn fn) : _fn{std::move(fn)} {
+      FnHolderImpl(BridgeT* bridge, Fn fn)
+        : _fn{std::move(fn)},
+          _bridge{bridge} {
       }
 
       // check arity and call the function using our little helper, before wrapping it back to json
       json call(std::vector<json> const& args) override {
-        if (args.size() != sizeof...(Arg)) {
-          throw std::runtime_error("Bridge method call with wrong arity, expected " + std::to_string(sizeof...(Arg)) + ", got " + std::to_string(args.size()) + ".");
+        if (args.size() != _num_args) {
+          throw std::runtime_error("Bridge method call with wrong arity, expected " + std::to_string(_num_args) + ", got " + std::to_string(args.size()) + ".");
         }
 
-        // generate an index_sequence so that the call_impl() can spread on each argument
-        return cook(call_impl(args, std::make_index_sequence<sizeof...(Arg)>{}));
+        return cook(call_impl(args, std::make_index_sequence<_num_args>{}));
       }
 
     };
 
   }
 
   class Bridge {
+    // store a wrapper FnHolder in the map, with FnHolderImpl to keep the correct types around and do FFI correctly
     std::unordered_map<std::string, std::unique_ptr<details::FnHolder>> _fns;
 
   public:
-    template<typename Ret, typename... Arg>
-    void bind(std::string const& name, std::function<Ret(Arg...)> fn) {
-      // store a wrapper FnHolder in the map, with FnHolderImpl to keep the correct types around and do FFI correctly
-      using HolderType = details::FnHolderImpl<Ret, Arg...>;
-      _fns[name] = std::make_unique<HolderType>(std::move(fn));
+    template<typename BridgeT, typename Fn>
+    auto bind(std::string const& name, BridgeT* obj, Fn fn)
+    -> typename std::enable_if<std::is_member_function_pointer<Fn>::value, void>::type {
+      static_assert(std::is_same<details::ct::class_of_t<Fn>, BridgeT>::value, "Bridge subclass must pass itself");
+
+      using HolderType = details::FnHolderImpl<BridgeT, Fn>;
+      _fns[name] = std::make_unique<HolderType>(obj, std::move(fn));
     }
 
-    template<typename Ret, typename... Arg>
-    void bind(std::string const& name, Ret(*fn)(Arg...)) {
-      bind(name, std::function<Ret(Arg...)>(fn));
+    template<typename Fn>
+    auto bind(std::string const& name, Fn fn)
+    -> typename std::enable_if<!std::is_member_function_pointer<Fn>::value, void>::type {
+      using HolderType = details::FnHolderImpl<std::nullptr_t, Fn>;
+      _fns[name] = std::make_unique<HolderType>(nullptr, std::move(fn));
     }
 
     nlohmann::json call(std::string const& name, std::vector<nlohmann::json> const& args);

src/cpp/lib/testml/run/tap.cpp

@@ -29,7 +29,7 @@ namespace run {
     std::cout << "\n";
   }
 
-  void TAP::testml_done() {
+  void TAP::testml_end() {
     std::cout << "1.." << count;
   }
 

src/cpp/lib/testml/run/tap.hpp

@@ -14,7 +14,7 @@ namespace run {
 
   protected:
     void testml_eq(json want, json got, std::string const& label) override;
-    void testml_done() override;
+    void testml_end() override;
 
   private:
     void tap_pass(std::string const& label);

src/cpp/lib/testml/runtime.cpp

@@ -8,6 +8,7 @@
 
 #include "runtime.hpp"
 #include "bridge.hpp"
+#include "utils.hpp"
 
 [[noreturn]] static void NYI(std::string const& add = "") {
   throw std::runtime_error("Not Yet Implemented, sorry! " + add);
@@ -17,12 +18,6 @@ using json = nlohmann::json;
 
 namespace testml {
 
-  namespace {
-    bool is_all_lowercase(std::string const& s) {
-      return std::all_of(s.begin(), s.end(), [](char c) { return std::islower(c); });
-    }
-  }
-
   Runtime::Runtime(std::string const& filename, Bridge& bridge)
     : _bridge{bridge} {
 
@@ -32,30 +27,35 @@ namespace testml {
     _data = _ast["data"];
   }
 
-  json Runtime::exec_expr(json fragment) {
-    if (!fragment.is_array() || fragment.size() == 0)
-      return json::array_t{fragment};
+  json Runtime::exec(json expr) {
+    json executed = exec_expr(expr);
+    return executed.size() > 0 ? executed[0] : static_cast<json>(nullptr);
+  }
 
-    // TODO check if the first element is a string, otherwise return it unwrapped
+  json Runtime::exec_expr(json expr) {
+    if (!expr.is_array() || expr.size() == 0 || !expr[0].is_string())
+      return json::array_t{expr};
 
-    std::string opcode = fragment[0];
-    fragment.erase(fragment.begin()); // pop first arg
+    std::string opcode = expr[0];
+    expr.erase(expr.begin()); // pop first arg
     json val;
+    // TODO vtable
     if (opcode == "%<>") {
-      // TODO bound check
-      // TODO std::unordered_map<std::string key, std::tuple<int arity, std::function call>>
-      each_pick(fragment[0], fragment[1]);
+      each_pick(expr[0], expr[1]);
       return {}; // no return value
     } else if (opcode == "==") {
-      assert_eq(fragment[0], fragment[1], fragment.size() == 3 ? fragment[2] : "");
+      assert_eq(expr[0], expr[1], expr.size() == 3 ? expr[2] : "");
       return {}; // no return value
     } else if (opcode == ".") {
-      val = exec_dot(fragment);
+      val = exec_dot(expr);
     } else if (opcode == "*") {
-      val = get_point(fragment[0]);
-    } else if (is_all_lowercase(opcode)) {
-      val = call_bridge(opcode, fragment);
+      val = get_point(expr[0]);
+    } else if (utils::is_all_lowercase(opcode)) {
+      val = call_bridge(opcode, expr);
+    } else if (utils::is_all_uppercase(opcode)) {
+      NYI("std lib");
     } else if (true) {
+      // TODO func
       NYI(opcode);
     } else {
       throw std::runtime_error("Can't resolve TestML function");
@@ -66,18 +66,22 @@ namespace testml {
   json Runtime::call_bridge(std::string const& name, json::array_t args) {
     std::vector<json> transformed;
     std::transform(args.begin(), args.end(), std::back_inserter(transformed),
-      [this](json& j) { return exec_expr(j)[0] /* TODO exec() */; });
+      [this](json& j) { return exec(j); });
     return _bridge.call(name, transformed);
   }
 
+  void Runtime::assert_eq(json::array_t left, json::array_t right, std::string const& label) {
+    testml_eq(exec_expr(left), exec_expr(right), label);
+  }
+
   json Runtime::get_point(std::string const& name) {
     return _currentBlock["point"][name];
   }
 
-  json Runtime::exec_dot(json::array_t fragment) {
+  json Runtime::exec_dot(json::array_t calls) {
     json context = {}; // result of last call
-    
-    for (auto call : fragment) {
+
+    for (auto call : calls) {
       // add context right after the opcode
       call.insert(call.begin() + 1 /* after opcode */, context.begin(), context.end());
       // we now have the full argument list
@@ -117,10 +121,6 @@ namespace testml {
     }
   }
 
-  void Runtime::assert_eq(json::array_t left, json::array_t right, std::string const& label) {
-    testml_eq(exec_expr(left), exec_expr(right), label);
-  }
-
   bool Runtime::is_function(json value) {
     if (!value.is_object()) {
       return false;
@@ -131,11 +131,11 @@ namespace testml {
     return value[0].is_string() && value[0] == "=>";
   }
 
-  void Runtime::run() {
+  void Runtime::test() {
     for (auto& statement : _ast["code"]) {
       exec_expr(statement);
     }
-    testml_done();
+    testml_end();
   }
 
   Runtime::~Runtime() {

src/cpp/lib/testml/runtime.hpp

@@ -15,7 +15,7 @@ namespace testml {
     Runtime(std::string const& filename, Bridge&);
     virtual ~Runtime() = 0;
 
-    void run();
+    void test();
 
   private:
     // toplevel methods
@@ -24,21 +24,24 @@ namespace testml {
 
   private:
     // other methods
-    json exec_expr(json fragment);
-    json exec_dot(json::array_t fragment);
+    json exec(json expr);
+    json exec_expr(json expr);
     json call_bridge(std::string const& name, json::array_t args);
     json get_point(std::string const& name);
 
   private:
     void assert_eq(json::array_t got, json::array_t want, std::string const& label);
 
+  private:
+    json exec_dot(json::array_t calls);
+
   private:
     bool is_function(json value);
 
   protected:
     // those methods are to be overriden by the runtime class implementing
     virtual void testml_eq(json want, json got, std::string const& label) = 0;
-    virtual void testml_done() = 0;
+    virtual void testml_end() = 0;
 
   private:
     Bridge& _bridge;

src/cpp/lib/testml/utils.cpp

@@ -0,0 +1,19 @@
+#include "utils.hpp"
+
+namespace testml {
+namespace utils {
+
+  bool is_all_lowercase(std::string const& s) {
+    return std::all_of(s.begin(), s.end(),
+      [](char c) { return std::islower(c); }
+    );
+  }
+
+  bool is_all_uppercase(std::string const& s) {
+    return std::all_of(s.begin(), s.end(),
+      [](char c) { return std::isupper(c); }
+    );
+  }
+
+}
+}

src/cpp/lib/testml/utils.hpp

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <string>
+
+namespace testml {
+namespace utils {
+
+  bool is_all_lowercase(std::string const& s);
+  bool is_all_uppercase(std::string const& s);
+
+  template<typename T>
+  struct remove_first_type
+  {
+  };
+
+  template<typename T, typename... Ts>
+  struct remove_first_type<std::tuple<T, Ts...>>
+  {
+    typedef std::tuple<Ts...> type;
+  };
+
+  template<>
+  struct remove_first_type<std::tuple<>>
+  {
+    typedef std::tuple<> type;
+  };
+
+}
+}

src/cpp/src/testml-run.cpp

@@ -2,19 +2,14 @@
 #include <exception>
 
 #include "../lib/testml/run/tap.hpp"
+#include "../test/testml-bridge.hpp"
 
 int main(int, char* argv[]) {
 
-  testml::Bridge bridge;
-  bridge.bind("add", +[](int a, int b) {
-    return a + b;
-  });
-  bridge.bind("sub", +[](int a, int b) {
-    return a - b;
-  });
+  TestMLBridge bridge;
   try {
     testml::run::TAP tap{argv[1], bridge};
-    tap.run();
+    tap.test();
   } catch (std::exception& e) {
     std::cout << "exception thrown: " << e.what() << std::endl;
   }

src/cpp/test/testml-bridge.cpp

@@ -0,0 +1,13 @@
+#include "testml-bridge.hpp"
+
+TestMLBridge::TestMLBridge() {
+  bind("add", this, &TestMLBridge::add);
+  bind("sub", [](int a, int b) {
+    return a - b;
+  });
+}
+
+int TestMLBridge::add(int a, int b) {
+  return a + b;
+}
+