add C++20 lambda template

Author: avitase

snippets/snippet18.cfg

@@ -1,5 +1,6 @@
 {
     "cpp_file": "snippet18.cpp",
-    "compiler": "g92",
+    "compiler": "clang900",
+    "flags": "-std=c++2a",
     "execute": true
 }

snippets/snippet18.cpp

@@ -1,14 +1,14 @@
 #include <cmath>
+#include <iostream>
 
 int main() {
-    auto y = [](auto x) {
-        using T = decltype(x);
+    auto y = []<typename T>(T x) {
         T mean = 1.;
         T width = 3.;
         auto norm = 1. / std::sqrt(2. * M_PI);
         auto arg = (x - mean) / width;
         return norm * std::exp(-.5 * arg * arg);
     }(.5);
-    
-    return y;
+
+    std::cout << y;
 }

snippets/snippet18_cpplst.tex

@@ -1,16 +1,16 @@
-\begin{lstlisting}[title=\href{https://godbolt.org/z/3-FVEE}{\texttt{godbolt.org/z/3-FVEE}}]
+\begin{lstlisting}[title=\href{https://godbolt.org/z/NC6DKj}{\texttt{godbolt.org/z/NC6DKj}}]
 #include <cmath>
+#include <iostream>
 
 int main() {
-    auto y = [](auto x) {
-        using T = decltype(x);
+    auto y = []<typename T>(T x) {
         T mean = 1.;
         T width = 3.;
         auto norm = 1. / std::sqrt(2. * M_PI);
         auto arg = (x - mean) / width;
         return norm * std::exp(-.5 * arg * arg);
     }(.5);
-    
-    return y;
+
+    std::cout << y;
 }
 \end{lstlisting}