set_help_flag now can replace a flag if needed, or remove it

README.md

@@ -132,8 +132,6 @@ app.add_set(option_name,
 
 app.add_set_ignore_case(... // String only
 
-app.add_help_flag(name, optional_discription);
-
 App* subcom = app.add_subcommand(name, discription);
 ```
 
@@ -163,7 +161,7 @@ The add commands return a pointer to an internally stored `Option`. If you set t
 * `->check(CLI::NonexistentPath)`: Requires that the path does not exist.
 * `->check(CLI::Range(min,max))`: Requires that the option be between min and max (make sure to use floating point if needed). Min defaults to 0.
 
-These options return the `Option` pointer, so you can chain them together, and even skip storing the pointer entirely. Check takes any function that has the signature `bool(std::string)`. If you want to change the default help option, it is available through `get_help_ptr`. If you just want to see the unconverted values, use `.results()` to get the `std::vector<std::string>` of results.
+These options return the `Option` pointer, so you can chain them together, and even skip storing the pointer entirely. Check takes any function that has the signature `bool(std::string)`. If you just want to see the unconverted values, use `.results()` to get the `std::vector<std::string>` of results.
 
 
 On the command line, options can be given as:
@@ -247,7 +245,7 @@ arguments, use `.config_to_str(default_also=false)`, where `default_also` will a
 
 ## Subclassing
 
-The App class was designed allow toolkits to subclass it, to provide default options and setup/teardown code. Subcommands remain an unsubclassed `App`, since those are not expected to need setup and teardown. The default `App` only adds a help flag, `-h,--help`, but provides an option to disable it in the constructor (and in `add_subcommand`). You can remove options if you have pointers to them using `.remove_option(opt)`. You can add a `pre_callback` override to customize the after parse
+The App class was designed allow toolkits to subclass it, to provide default options and setup/teardown code. Subcommands remain an unsubclassed `App`, since those are not expected to need setup and teardown. The default `App` only adds a help flag, `-h,--help`, but provides an option to disable it in the constructor (and in `add_subcommand`), and can removed/replaced using `.set_help_flag(name, help_string)`. You can remove options if you have pointers to them using `.remove_option(opt)`. You can add a `pre_callback` override to customize the after parse
 but before run behavior, while
 still giving the user freedom to `set_callback` on the main app.  
 

include/CLI/App.hpp

@@ -140,7 +140,7 @@ class App {
     App(std::string description_, bool help, detail::enabler) : description_(std::move(description_)) {
 
         if(help)
-            add_help_flag("-h,--help", "Print this help message and exit");
+            set_help_flag("-h,--help", "Print this help message and exit");
     }
 
   public:
@@ -331,11 +331,17 @@ class App {
         return opt;
     }
 
-    /// Add a help flag, replaced the existing one if present
-    Option *add_help_flag(std::string name, std::string description = "") {
-        if(help_ptr_ != nullptr)
+    /// Set a help flag, replaced the existing one if present
+    Option *set_help_flag(std::string name = "", std::string description = "") {
+        if(help_ptr_ != nullptr) {
             remove_option(help_ptr_);
-        help_ptr_ = add_flag(name, description);
+            help_ptr_ = nullptr;
+        }
+
+        // Empty name will simply remove the help flag
+        if(!name.empty())
+            help_ptr_ = add_flag(name, description);
+
         return help_ptr_;
     }
 

tests/HelpTest.cpp

@@ -287,12 +287,30 @@ TEST(THelp, OnlyOneHelp) {
     CLI::App app{"My prog"};
 
     // It is not supported to have more than one help flag, last one wins
-    app.add_help_flag("--help", "No short name allowed");
-    app.add_help_flag("--yelp", "Alias for help");
+    app.set_help_flag("--help", "No short name allowed");
+    app.set_help_flag("--yelp", "Alias for help");
 
     std::vector<std::string> input{"--help"};
     EXPECT_THROW(app.parse(input), CLI::ExtrasError);
-
+}
+
+TEST(THelp, RemoveHelp) {
+    CLI::App app{"My prog"};
+    app.set_help_flag();
+
+    std::string help = app.help();
+
+    EXPECT_THAT(help, HasSubstr("My prog"));
+    EXPECT_THAT(help, Not(HasSubstr("-h,--help")));
+    EXPECT_THAT(help, Not(HasSubstr("Options:")));
+    EXPECT_THAT(help, HasSubstr("Usage:"));
+
+    std::vector<std::string> input{"--help"};
+    try {
+        app.parse(input);
+    } catch(const CLI::ParseError &e) {
+        EXPECT_EQ(static_cast<int>(CLI::ExitCodes::Extras), e.get_exit_code());
+    }
 }
 
 TEST(THelp, NoHelp) {
@@ -316,7 +334,7 @@ TEST(THelp, NoHelp) {
 TEST(THelp, CustomHelp) {
     CLI::App app{"My prog", false};
 
-    CLI::Option *help_option = app.add_help_flag("--yelp", "display help and exit");
+    CLI::Option *help_option = app.set_help_flag("--yelp", "display help and exit");
     EXPECT_EQ(app.get_help_ptr(), help_option);
 
     std::string help = app.help();