Writing argument description to config string (issue #65)

include/CLI/App.hpp

@@ -809,35 +809,47 @@ class App {
 
     /// Produce a string that could be read in as a config of the current values of the App. Set default_also to include
     /// default arguments. Prefix will add a string to the beginning of each option.
-    std::string config_to_str(bool default_also = false, std::string prefix = "") const {
+    std::string
+    config_to_str(bool default_also = false, std::string prefix = "", bool write_description = false) const {
         std::stringstream out;
         for(const Option_p &opt : options_) {
 
             // Only process option with a long-name and configurable
             if(!opt->lnames_.empty() && opt->get_configurable()) {
                 std::string name = prefix + opt->lnames_[0];
+                std::string value;
 
                 // Non-flags
                 if(opt->get_expected() != 0) {
 
                     // If the option was found on command line
                     if(opt->count() > 0)
-                        out << name << "=" << detail::inijoin(opt->results()) << std::endl;
+                        value = detail::inijoin(opt->results());
 
                     // If the option has a default and is requested by optional argument
                     else if(default_also && !opt->defaultval_.empty())
-                        out << name << "=" << opt->defaultval_ << std::endl;
+                        value = opt->defaultval_;
                     // Flag, one passed
                 } else if(opt->count() == 1) {
-                    out << name << "=true" << std::endl;
+                    value = "true";
 
                     // Flag, multiple passed
                 } else if(opt->count() > 1) {
-                    out << name << "=" << opt->count() << std::endl;
+                    value = std::to_string(opt->count());
 
                     // Flag, not present
                 } else if(opt->count() == 0 && default_also) {
-                    out << name << "=false" << std::endl;
+                    value = "false";
+                }
+
+                if(!value.empty()) {
+                    if(write_description && opt->has_description()) {
+                        if(static_cast<int>(out.tellp()) != 0) {
+                            out << std::endl;
+                        }
+                        out << "; " << detail::fix_newlines("; ", opt->get_description()) << std::endl;
+                    }
+                    out << name << "=" << value << std::endl;
                 }
             }
         }

include/CLI/StringTools.hpp

@@ -187,5 +187,21 @@ inline std::vector<std::string> split_up(std::string str) {
     return output;
 }
 
+/// Add a leader to the beginning of all new lines (nothing is added
+/// at the start of the first line). `"; "` would be for ini files
+///
+/// Can't use Regex, or this would be a subs.
+inline std::string fix_newlines(std::string leader, std::string input) {
+    std::string::size_type n = 0;
+    while(n != std::string::npos && n < input.size()) {
+        n = input.find('\n', n);
+        if(n != std::string::npos) {
+            input = input.substr(0, n + 1) + leader + input.substr(n + 1);
+            n += leader.size();
+        }
+    }
+    return input;
+}
+
 } // namespace detail
 } // namespace CLI

tests/HelpersTest.cpp

@@ -359,3 +359,17 @@ TEST(Types, LexicalCastString) {
     CLI::detail::lexical_cast(input, output);
     EXPECT_EQ(input, output);
 }
+
+TEST(FixNewLines, BasicCheck) {
+    std::string input = "one\ntwo";
+    std::string output = "one\n; two";
+    std::string result = CLI::detail::fix_newlines("; ", input);
+    EXPECT_EQ(result, output);
+}
+
+TEST(FixNewLines, EdgesCheck) {
+    std::string input = "\none\ntwo\n";
+    std::string output = "\n; one\n; two\n; ";
+    std::string result = CLI::detail::fix_newlines("; ", input);
+    EXPECT_EQ(result, output);
+}

tests/IniTest.cpp

@@ -575,6 +575,44 @@ TEST_F(TApp, IniOutputNoConfigurable) {
     EXPECT_EQ("simple=3\n", str);
 }
 
+TEST_F(TApp, IniOutputShortSingleDescription) {
+    std::string flag = "some_flag";
+    std::string description = "Some short description.";
+    app.add_flag("--" + flag, description);
+
+    run();
+
+    std::string str = app.config_to_str(true, "", true);
+    EXPECT_THAT(str, HasSubstr("; " + description + "\n" + flag + "=false\n"));
+}
+
+TEST_F(TApp, IniOutputShortDoubleDescription) {
+    std::string flag1 = "flagnr1";
+    std::string flag2 = "flagnr2";
+    std::string description1 = "First description.";
+    std::string description2 = "Second description.";
+    app.add_flag("--" + flag1, description1);
+    app.add_flag("--" + flag2, description2);
+
+    run();
+
+    std::string str = app.config_to_str(true, "", true);
+    EXPECT_EQ(str, "; " + description1 + "\n" + flag1 + "=false\n\n; " + description2 + "\n" + flag2 + "=false\n");
+}
+
+TEST_F(TApp, IniOutputMultiLineDescription) {
+    std::string flag = "some_flag";
+    std::string description = "Some short description.\nThat has lines.";
+    app.add_flag("--" + flag, description);
+
+    run();
+
+    std::string str = app.config_to_str(true, "", true);
+    EXPECT_THAT(str, HasSubstr("; Some short description.\n"));
+    EXPECT_THAT(str, HasSubstr("; That has lines.\n"));
+    EXPECT_THAT(str, HasSubstr(flag + "=false\n"));
+}
+
 TEST_F(TApp, IniOutputVector) {
 
     std::vector<int> v;