Squashed 'libs/cli11/' content from commit dcbcb47

git-subtree-dir: libs/cli11
git-subtree-split: dcbcb4721dda5dab0a56d9faaaee50e6a30f7758

examples/custom_parse.cpp

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+// Copyright (c) 2017-2022, University of Cincinnati, developed by Henry Schreiner
+// under NSF AWARD 1414736 and by the respective contributors.
+// All rights reserved.
+//
+// SPDX-License-Identifier: BSD-3-Clause
+
+// from Issue #566 on github https://github.com/CLIUtils/CLI11/issues/566
+
+#include <CLI/CLI.hpp>
+#include <iostream>
+#include <sstream>
+
+// example file to demonstrate a custom lexical cast function
+
+template <class T = int> struct Values {
+    T a;
+    T b;
+    T c;
+};
+
+// in C++20 this is constructible from a double due to the new aggregate initialization in C++20.
+using DoubleValues = Values<double>;
+
+// the lexical cast operator should be in the same namespace as the type for ADL to work properly
+bool lexical_cast(const std::string &input, Values<double> & /*v*/) {
+    std::cout << "called correct lexical_cast function ! val: " << input << std::endl;
+    return true;
+}
+
+DoubleValues doubles;
+void argparse(CLI::Option_group *group) { group->add_option("--dv", doubles)->default_str("0"); }
+
+int main(int argc, char **argv) {
+    CLI::App app;
+
+    argparse(app.add_option_group("param"));
+    CLI11_PARSE(app, argc, argv);
+    return 0;
+}