Created 'Apply' Node which will apply a std::function to two arguments, allowing for the user to submit whatever function they want to provide on the operator such as standard ones like std::plus. Also extended the compile time string by giving it a constexpr compatible equality and plus operator (string concating)

Author: shaerthomas

lookuptable.h

@@ -1,4 +1,5 @@
 #include <iostream>
+#include "specialtypes.h"
 
 /*
 Compile time datastructure used for mapping variable names to values.
@@ -15,29 +16,7 @@ Registering new identifiers (and values)
 
 
 
-/*
-Compatible string literal compile time type (used for ids)
-
-https://stackoverflow.com/questions/62853609/understanding-user-defined-string-literals-addition-for-c20
-*/
-template<size_t N>
-struct string_literal
-{
-    std::array<char, N> arr_;
-
-    constexpr string_literal(const char(&in)[N]) : arr_{}   
-    {
-        std::copy(in, in + N, arr_.begin());
-    }
-
-    friend std::ostream& operator<<(std::ostream& os, const string_literal& dt)
-    {
-        //std::string lol(arr_;
-        os << std::string(dt.arr_.data());
-        return os;
-    }
 
-};
 
 
 

main

@@ -80,26 +80,28 @@ int main(int argc, char* argv[])
     runTests();
     /*
     TODO.
-    Make it so that you don't have to explicitly pass in a linkedlist item to Execute
+    Make it so that you don't have to explicitly pass in a linkedlist item to Execute.
+
+    Make it so that the Apply function takes in any amount of arguments
     */
 
 
 
     using code = Execute<LinkedListEmptyNode,
                          Assign<"x", ValNum<6>>,
-                         Assign<"y", BinOpPlus<ValNum<2>, Var<"x">>>,
-                         Assign<"z", BinOpPlus<BinOpPlus<Var<"y">, ValNum<10>>, ValNum<7>>>,
-                         Assign<"a", ValStr<"Hello World!">>>;
+                         Assign<"y", Apply<std::plus<>, ValNum<2>, Var<"x">>>,
+                         Assign<"z", Apply<std::plus<>, Apply<std::multiplies<>, Var<"y">, ValNum<10>>, ValNum<7>>>,
+                         Assign<"text", ValStr<"Hello ">>,
+                         Assign<"text2", Apply<std::plus<>, Var<"text">, ValStr<"World!">>>>;
 
     static_assert(LinkedListGetValue<code::values, "x">::value == 6);
     static_assert(LinkedListGetValue<code::values, "y">::value == 8);
-    static_assert(LinkedListGetValue<code::values, "z">::value == 25);
-    std::cout << LinkedListGetValue<code::values, "a">::value << std::endl;
-    //static_assert(LinkedListGetValue<code::values, "z">::value == 25);
+    static_assert(LinkedListGetValue<code::values, "z">::value == 87);
+    constexpr string_literal teststring = "Hello World!";
+
+    
+    static_assert(LinkedListGetValue<code::values, "text2">::value == teststring);
 
-    // std::cout << LinkedListGetValue<code::values, "x">::value << std::endl;
-    // std::cout << LinkedListGetValue<code::values, "y">::value << std::endl;
-    // std::cout << LinkedListGetValue<code::values, "z">::value << std::endl;
 
 
 

main.cpp

@@ -46,12 +46,12 @@ struct Var {
 };
 
 
-template<typename A, typename B>
-struct BinOpPlus {
+template<typename Func, typename A, typename B>
+struct Apply {
 
     template<typename SymbolTable>
     static const constexpr auto getValue() {
-        return A::template getValue<SymbolTable>() + B::template getValue<SymbolTable>();
+        return Func{}(A::template getValue<SymbolTable>(), B::template getValue<SymbolTable>());
     }
 };
 

node.h

@@ -0,0 +1,59 @@
+#include <iostream>
+
+/*
+Compatible string literal compile time type (used for ids)
+
+https://stackoverflow.com/questions/62853609/understanding-user-defined-string-literals-addition-for-c20
+
+*/
+
+
+#include <array>
+#include <algorithm>
+
+
+
+template<size_t N>
+struct string_literal
+{
+    std::array<char, N> arr_;
+
+    constexpr string_literal(const char(&in)[N]) : arr_{}   
+    {
+        std::copy(in, in + N, arr_.begin());
+    }
+
+    constexpr string_literal(std::array<char, N> a) : arr_{a}   
+    {
+    }
+
+    friend std::ostream& operator<<(std::ostream& os, const string_literal& dt)
+    {
+        os << std::string(dt.arr_.data());
+        return os;
+    }
+
+
+
+};
+
+template<template <size_t> typename String1, size_t StringSize1,
+        template <size_t> typename String2, size_t StringSize2>
+constexpr bool operator==(const String1<StringSize1>& a, const String2<StringSize2>& b) {
+        return a.arr_ == b.arr_;
+    }
+
+template<template <size_t> typename String1, size_t StringSize1,
+        template <size_t> typename String2, size_t StringSize2>
+constexpr string_literal<(StringSize1 + StringSize2)-1>  operator+(const String1<StringSize1>& a, const String2<StringSize2>& b) {
+
+        std::array<char, StringSize1 + StringSize2-1> temp;
+
+        std::copy_n(a.arr_.begin(), StringSize1-1 , std::begin(temp));
+        std::copy_n(b.arr_.begin(), StringSize2 ,std::begin(temp) + StringSize1  - 1);
+
+
+        string_literal<(StringSize1 + StringSize2)-1> temp2 = temp;
+
+        return temp2;
+    }