Add reflection for binary expressions, and first working autodiff example

The test @autodiff function can now handle the "r = a + b;" case.

This code:

   test: @autodiff @print type = {

      // A simple first function would be:
      // func: (a: double, b: double) -> double = { return a + b; }
      func: (a: double, b: double) -> (r: double) = { r = a + b; }

      // The generated autodiff forward transformation would be:
      // func_diff: (a: double, a_d: double, b: double, b_d: double) -> (r: double, r_d: double) = {
      //     r_d = a * b_d + b * a_d;
      //     r = a * b;
      // }

   }

Generates the following, as reported by @print in the cppfront compile output:

   test:/* @autodiff @print */ type =
   {
      func:(
         in a: double,
         in b: double,
      ) -> (out r: double, ) =
      {
         r = a + b;
         return;
      }

      func_diff:(
         in a: double,
         in a_d: double,
         in b: double,
         in b_d: double,
      ) -> (
               out r: double = 1,
               out r_d: double = 1,
         ) =
      {
         r_d = a * b_d + b * a_d;
         r = a * b;
         return;
      }
   }

And a bug fix: When a file that contains Cpp2 code begins with Cpp1 #includes, preserve their position at the top of the generated file too. This allows a Cpp2 type's template parameter list to use types a from Cpp1 header file.

Author: hsutter

build_h2.bat

@@ -1,6 +1,6 @@
 @echo off
 cd source
-cppfront reflect.h2 -verb
+cppfront reflect.h2 -verb %1
 cd ..\include
-cppfront cpp2regex.h2 -verb
+cppfront cpp2regex.h2 -verb %1
 cd..

regression-tests/test-results/mixed-bounds-check.cpp

@@ -1,3 +1,5 @@
+#line 2 "mixed-bounds-check.cpp2"
+#include <vector>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -12,8 +14,6 @@
 
 #line 1 "mixed-bounds-check.cpp2"
 
-#include <vector>
-
 #line 4 "mixed-bounds-check.cpp2"
 [[nodiscard]] auto main() -> int;
 

regression-tests/test-results/mixed-bugfix-for-literal-as-nttp.cpp

@@ -1,3 +1,4 @@
+#include <chrono>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -11,7 +12,8 @@
 //=== Cpp2 type definitions and function declarations ===========================
 
 #line 1 "mixed-bugfix-for-literal-as-nttp.cpp2"
-#include <chrono>
+
+#line 2 "mixed-bugfix-for-literal-as-nttp.cpp2"
 auto main() -> int;
 
 //=== Cpp2 function definitions =================================================

regression-tests/test-results/mixed-captures-in-expressions-and-postconditions.cpp

@@ -1,3 +1,6 @@
+#line 2 "mixed-captures-in-expressions-and-postconditions.cpp2"
+#include <algorithm>
+#include <vector>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -12,9 +15,6 @@
 
 #line 1 "mixed-captures-in-expressions-and-postconditions.cpp2"
 
-#include <algorithm>
-#include <vector>
-
 #line 5 "mixed-captures-in-expressions-and-postconditions.cpp2"
 [[nodiscard]] auto main() -> int;
 

regression-tests/test-results/mixed-fixed-type-aliases.cpp

@@ -1,3 +1,6 @@
+#include <filesystem>
+#include <iostream>
+#include <typeinfo>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -14,9 +17,7 @@ template<typename T> class mytype;
 //=== Cpp2 type definitions and function declarations ===========================
 
 #line 1 "mixed-fixed-type-aliases.cpp2"
-#include <filesystem>
-#include <iostream>
-#include <typeinfo>
+#line 4 "mixed-fixed-type-aliases.cpp2"
 
 namespace my {
     using u16 = float;

regression-tests/test-results/mixed-forwarding.cpp

@@ -1,3 +1,5 @@
+#include <iostream>
+#include <utility>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -11,8 +13,7 @@
 //=== Cpp2 type definitions and function declarations ===========================
 
 #line 1 "mixed-forwarding.cpp2"
-#include <iostream>
-#include <utility>
+#line 3 "mixed-forwarding.cpp2"
 
 struct X {
     int i;

regression-tests/test-results/mixed-function-expression-and-std-for-each.cpp

@@ -1,3 +1,8 @@
+#include <vector>
+#include <string>
+#include <span>
+#include <algorithm>
+#include <iostream>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -11,11 +16,6 @@
 //=== Cpp2 type definitions and function declarations ===========================
 
 #line 1 "mixed-function-expression-and-std-for-each.cpp2"
-#include <vector>
-#include <string>
-#include <span>
-#include <algorithm>
-#include <iostream>
 
 #line 7 "mixed-function-expression-and-std-for-each.cpp2"
 [[nodiscard]] auto main() -> int;

regression-tests/test-results/mixed-function-expression-and-std-ranges-for-each-with-capture.cpp

@@ -1,3 +1,9 @@
+#include <vector>
+#include <ranges>
+#include <string>
+#include <span>
+#include <algorithm>
+#include <iostream>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -11,12 +17,6 @@
 //=== Cpp2 type definitions and function declarations ===========================
 
 #line 1 "mixed-function-expression-and-std-ranges-for-each-with-capture.cpp2"
-#include <vector>
-#include <ranges>
-#include <string>
-#include <span>
-#include <algorithm>
-#include <iostream>
 
 #line 8 "mixed-function-expression-and-std-ranges-for-each-with-capture.cpp2"
 [[nodiscard]] auto main() -> int;

regression-tests/test-results/mixed-function-expression-and-std-ranges-for-each.cpp

@@ -1,3 +1,9 @@
+#include <vector>
+#include <ranges>
+#include <string>
+#include <span>
+#include <algorithm>
+#include <iostream>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -11,12 +17,6 @@
 //=== Cpp2 type definitions and function declarations ===========================
 
 #line 1 "mixed-function-expression-and-std-ranges-for-each.cpp2"
-#include <vector>
-#include <ranges>
-#include <string>
-#include <span>
-#include <algorithm>
-#include <iostream>
 
 #line 8 "mixed-function-expression-and-std-ranges-for-each.cpp2"
 [[nodiscard]] auto main() -> int;

regression-tests/test-results/mixed-function-expression-with-pointer-capture.cpp

@@ -1,3 +1,9 @@
+#include <vector>
+#include <ranges>
+#include <string>
+#include <span>
+#include <algorithm>
+#include <iostream>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -11,12 +17,6 @@
 //=== Cpp2 type definitions and function declarations ===========================
 
 #line 1 "mixed-function-expression-with-pointer-capture.cpp2"
-#include <vector>
-#include <ranges>
-#include <string>
-#include <span>
-#include <algorithm>
-#include <iostream>
 
 #line 8 "mixed-function-expression-with-pointer-capture.cpp2"
 [[nodiscard]] auto main() -> int;

regression-tests/test-results/mixed-function-expression-with-repeated-capture.cpp

@@ -1,3 +1,9 @@
+#include <vector>
+#include <ranges>
+#include <string>
+#include <span>
+#include <algorithm>
+#include <iostream>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -11,12 +17,6 @@
 //=== Cpp2 type definitions and function declarations ===========================
 
 #line 1 "mixed-function-expression-with-repeated-capture.cpp2"
-#include <vector>
-#include <ranges>
-#include <string>
-#include <span>
-#include <algorithm>
-#include <iostream>
 
 #line 8 "mixed-function-expression-with-repeated-capture.cpp2"
 [[nodiscard]] auto main() -> int;

regression-tests/test-results/mixed-hello.cpp

@@ -1,3 +1,6 @@
+#line 2 "mixed-hello.cpp2"
+#include <iostream>
+#include <string>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -12,9 +15,6 @@
 
 #line 1 "mixed-hello.cpp2"
 
-#include <iostream>
-#include <string>
-
 #line 5 "mixed-hello.cpp2"
 [[nodiscard]] auto name() -> std::string;
 

regression-tests/test-results/mixed-initialization-safety-3-contract-violation.cpp

@@ -1,3 +1,6 @@
+#include <random>
+#include <string>
+#include <vector>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -11,9 +14,6 @@
 //=== Cpp2 type definitions and function declarations ===========================
 
 #line 1 "mixed-initialization-safety-3-contract-violation.cpp2"
-#include <random>
-#include <string>
-#include <vector>
 
 #line 5 "mixed-initialization-safety-3-contract-violation.cpp2"
 [[nodiscard]] auto main() -> int;

regression-tests/test-results/mixed-initialization-safety-3.cpp

@@ -1,3 +1,6 @@
+#include <random>
+#include <string>
+#include <vector>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -11,9 +14,6 @@
 //=== Cpp2 type definitions and function declarations ===========================
 
 #line 1 "mixed-initialization-safety-3.cpp2"
-#include <random>
-#include <string>
-#include <vector>
 
 #line 5 "mixed-initialization-safety-3.cpp2"
 [[nodiscard]] auto main() -> int;

regression-tests/test-results/mixed-inspect-templates.cpp

@@ -1,3 +1,6 @@
+#include <vector>
+#include <array>
+#include <string>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -11,9 +14,7 @@
 //=== Cpp2 type definitions and function declarations ===========================
 
 #line 1 "mixed-inspect-templates.cpp2"
-#include <vector>
-#include <array>
-#include <string>
+#line 4 "mixed-inspect-templates.cpp2"
 
 template <typename A, typename B>
 struct my_type {};

regression-tests/test-results/mixed-inspect-values-2.cpp

@@ -1,3 +1,6 @@
+#line 2 "mixed-inspect-values-2.cpp2"
+#include <iostream>
+#include <vector>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -12,8 +15,7 @@
 
 #line 1 "mixed-inspect-values-2.cpp2"
 
-#include <iostream>
-#include <vector>
+#line 4 "mixed-inspect-values-2.cpp2"
 
 constexpr auto less_than = [](int value) {
     return [=](auto x) { return x < value;};

regression-tests/test-results/mixed-lifetime-safety-and-null-contracts.cpp

@@ -1,3 +1,7 @@
+#line 2 "mixed-lifetime-safety-and-null-contracts.cpp2"
+#include <iostream>
+#include <vector>
+#include <string>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -12,10 +16,6 @@
 
 #line 1 "mixed-lifetime-safety-and-null-contracts.cpp2"
 
-#include <iostream>
-#include <vector>
-#include <string>
-
 #line 6 "mixed-lifetime-safety-and-null-contracts.cpp2"
 [[nodiscard]] auto main() -> int;
 #line 11 "mixed-lifetime-safety-and-null-contracts.cpp2"

regression-tests/test-results/mixed-lifetime-safety-pointer-init-4.cpp

@@ -1,3 +1,6 @@
+#line 2 "mixed-lifetime-safety-pointer-init-4.cpp2"
+#include <iostream>
+#include <random>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -12,9 +15,6 @@
 
 #line 1 "mixed-lifetime-safety-pointer-init-4.cpp2"
 
-#include <iostream>
-#include <random>
-
 #line 5 "mixed-lifetime-safety-pointer-init-4.cpp2"
 [[nodiscard]] auto main() -> int;
 

regression-tests/test-results/mixed-multiple-return-values.cpp

@@ -1,3 +1,7 @@
+#line 2 "mixed-multiple-return-values.cpp2"
+#include <iostream>
+#include <random>
+#include <string>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -12,9 +16,6 @@
 
 #line 1 "mixed-multiple-return-values.cpp2"
 
-#include <iostream>
-#include <random>
-#include <string>
 
 struct f_ret { int i; std::string s; };
 

regression-tests/test-results/mixed-out-destruction.cpp

@@ -1,3 +1,4 @@
+#include <iostream>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -11,7 +12,7 @@
 //=== Cpp2 type definitions and function declarations ===========================
 
 #line 1 "mixed-out-destruction.cpp2"
-#include <iostream>
+#line 2 "mixed-out-destruction.cpp2"
 
 struct X {
     inline static int Xnum = 0;

regression-tests/test-results/mixed-parameter-passing-generic-out.cpp

@@ -1,3 +1,4 @@
+#include <iostream>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -11,7 +12,7 @@
 //=== Cpp2 type definitions and function declarations ===========================
 
 #line 1 "mixed-parameter-passing-generic-out.cpp2"
-#include <iostream>
+#line 2 "mixed-parameter-passing-generic-out.cpp2"
 
 struct X {
     X(int) { }

regression-tests/test-results/mixed-parameter-passing-with-forward.cpp

@@ -1,3 +1,7 @@
+#line 2 "mixed-parameter-passing-with-forward.cpp2"
+#include <string>
+#include <cstdlib>
+#include <ctime>
 
 
 //=== Cpp2 type declarations ====================================================
@@ -12,10 +16,6 @@
 
 #line 1 "mixed-parameter-passing-with-forward.cpp2"
 
-#include <string>
-#include <cstdlib>
-#include <ctime>
-
 #line 6 "mixed-parameter-passing-with-forward.cpp2"
 auto copy_from([[maybe_unused]] auto unnamed_param_1) -> void;