initial commit

libs/CLI11/examples/json.cpp

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+// Copyright (c) 2017-2021, 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
+
+#include <CLI/CLI.hpp>
+#include <iostream>
+#include <memory>
+#include <nlohmann/json.hpp>
+#include <string>
+#include <vector>
+
+// This example is only built on GCC 7 on Travis due to mismatch in stdlib
+// for clang (CLI11 is forgiving about mismatches, json.hpp is not)
+
+using nlohmann::json;
+
+class ConfigJSON : public CLI::Config {
+  public:
+    std::string to_config(const CLI::App *app, bool default_also, bool, std::string) const override {
+
+        json j;
+
+        for(const CLI::Option *opt : app->get_options({})) {
+
+            // Only process option with a long-name and configurable
+            if(!opt->get_lnames().empty() && opt->get_configurable()) {
+                std::string name = opt->get_lnames()[0];
+
+                // Non-flags
+                if(opt->get_type_size() != 0) {
+
+                    // If the option was found on command line
+                    if(opt->count() == 1)
+                        j[name] = opt->results().at(0);
+                    else if(opt->count() > 1)
+                        j[name] = opt->results();
+
+                    // If the option has a default and is requested by optional argument
+                    else if(default_also && !opt->get_default_str().empty())
+                        j[name] = opt->get_default_str();
+
+                    // Flag, one passed
+                } else if(opt->count() == 1) {
+                    j[name] = true;
+
+                    // Flag, multiple passed
+                } else if(opt->count() > 1) {
+                    j[name] = opt->count();
+
+                    // Flag, not present
+                } else if(opt->count() == 0 && default_also) {
+                    j[name] = false;
+                }
+            }
+        }
+
+        for(const CLI::App *subcom : app->get_subcommands({}))
+            j[subcom->get_name()] = json(to_config(subcom, default_also, false, ""));
+
+        return j.dump(4);
+    }
+
+    std::vector<CLI::ConfigItem> from_config(std::istream &input) const override {
+        json j;
+        input >> j;
+        return _from_config(j);
+    }
+
+    std::vector<CLI::ConfigItem>
+    _from_config(json j, std::string name = "", std::vector<std::string> prefix = {}) const {
+        std::vector<CLI::ConfigItem> results;
+
+        if(j.is_object()) {
+            for(json::iterator item = j.begin(); item != j.end(); ++item) {
+                auto copy_prefix = prefix;
+                if(!name.empty())
+                    copy_prefix.push_back(name);
+                auto sub_results = _from_config(*item, item.key(), copy_prefix);
+                results.insert(results.end(), sub_results.begin(), sub_results.end());
+            }
+        } else if(!name.empty()) {
+            results.emplace_back();
+            CLI::ConfigItem &res = results.back();
+            res.name = name;
+            res.parents = prefix;
+            if(j.is_boolean()) {
+                res.inputs = {j.get<bool>() ? "true" : "false"};
+            } else if(j.is_number()) {
+                std::stringstream ss;
+                ss << j.get<double>();
+                res.inputs = {ss.str()};
+            } else if(j.is_string()) {
+                res.inputs = {j.get<std::string>()};
+            } else if(j.is_array()) {
+                for(std::string ival : j)
+                    res.inputs.push_back(ival);
+            } else {
+                throw CLI::ConversionError("Failed to convert " + name);
+            }
+        } else {
+            throw CLI::ConversionError("You must make all top level values objects in json!");
+        }
+
+        return results;
+    }
+};
+
+int main(int argc, char **argv) {
+    CLI::App app;
+    app.config_formatter(std::make_shared<ConfigJSON>());
+
+    int item;
+
+    app.add_flag("--simple");
+    app.add_option("--item", item);
+    app.set_config("--config");
+
+    CLI11_PARSE(app, argc, argv);
+
+    std::cout << app.config_to_str(true, true) << std::endl;
+}