init

cmake/external/glib/cppgir/expected-lite/example/01-basic.cpp

@@ -0,0 +1,33 @@
+// Convert text to number and yield expected with number or error text.
+
+#include "nonstd/expected.hpp"
+
+#include <cstdlib>
+#include <iostream>
+#include <string>
+
+using namespace nonstd;
+using namespace std::literals;
+
+auto to_int( char const * const text ) -> expected<int, std::string>
+{
+    char * pos = nullptr;
+    auto value = strtol( text, &pos, 0 );
+
+    if ( pos != text ) return value;
+    else               return make_unexpected( "'"s + text + "' isn't a number" );
+}
+
+int main( int argc, char * argv[] )
+{
+    auto text = argc > 1 ? argv[1] : "42";
+
+    auto ei = to_int( text );
+
+    if ( ei ) std::cout << "'" << text << "' is " << *ei << ", ";
+    else      std::cout << "Error: " << ei.error();
+}
+
+// cl -EHsc -wd4814 -I../include 01-basic.cpp && 01-basic.exe 123 && 01-basic.exe abc
+// g++ -std=c++14 -Wall -I../include -o 01-basic.exe 01-basic.cpp && 01-basic.exe 123 && 01-basic.exe abc
+// '123' is 123, Error: 'abc' isn't a number