Version add (#452)

* Add a dedicated version option to CLI11 to facilitate use of version flags, similar to help flags

* add some test for the version flag

* update errors and formatting

* clear up gcc 4.8 warnings

* add a few more tests

* fix compiler error

* fix a few comments, and change default version flag to only use "--version"

* remove `version` calls and tests

* formatting and add `std::string version()`  back in.

examples/CMakeLists.txt

@@ -54,6 +54,9 @@ set_property(TEST simple_all PROPERTY PASS_REGULAR_EXPRESSION
     "Received flag: 2 (2) times"
     "Some value: 1.2")
 
+add_test(NAME simple_version COMMAND simple --version)
+set_property(TEST simple_version PROPERTY PASS_REGULAR_EXPRESSION
+    "${CLI11_VERSION}")
 
 add_cli_exe(subcommands subcommands.cpp)
 add_test(NAME subcommands_none COMMAND subcommands)

examples/simple.cpp

@@ -11,7 +11,8 @@
 int main(int argc, char **argv) {
 
     CLI::App app("K3Pi goofit fitter");
-
+    // add version output
+    app.set_version_flag("--version", std::string(CLI11_VERSION));
     std::string file;
     CLI::Option *opt = app.add_option("-f,--file,file", file, "File name");
 

include/CLI/App.hpp

@@ -139,6 +139,9 @@ class App {
     /// A pointer to the help all flag if there is one INHERITABLE
     Option *help_all_ptr_{nullptr};
 
+    /// A pointer to a version flag if there is one
+    Option *version_ptr_{nullptr};
+
     /// This is the formatter for help printing. Default provided. INHERITABLE (same pointer)
     std::shared_ptr<FormatterBase> formatter_{new Formatter()};
 
@@ -703,6 +706,45 @@ class App {
         return help_all_ptr_;
     }
 
+    /// Set a version flag and version display string, replace the existing one if present
+    Option *set_version_flag(std::string flag_name = "", const std::string &versionString = "") {
+        // take flag_description by const reference otherwise add_flag tries to assign to version_description
+        if(version_ptr_ != nullptr) {
+            remove_option(version_ptr_);
+            version_ptr_ = nullptr;
+        }
+
+        // Empty name will simply remove the version flag
+        if(!flag_name.empty()) {
+            version_ptr_ = add_flag_callback(
+                flag_name,
+                [versionString]() { throw(CLI::CallForVersion(versionString, 0)); },
+                "display program version information and exit");
+            version_ptr_->configurable(false);
+        }
+
+        return version_ptr_;
+    }
+    /// Generate the version string through a callback function
+    Option *set_version_flag(std::string flag_name, std::function<std::string()> vfunc) {
+        // take flag_description by const reference otherwise add_flag tries to assign to version_description
+        if(version_ptr_ != nullptr) {
+            remove_option(version_ptr_);
+            version_ptr_ = nullptr;
+        }
+
+        // Empty name will simply remove the version flag
+        if(!flag_name.empty()) {
+            version_ptr_ = add_flag_callback(
+                flag_name,
+                [vfunc]() { throw(CLI::CallForVersion(vfunc(), 0)); },
+                "display program version information and exit");
+            version_ptr_->configurable(false);
+        }
+
+        return version_ptr_;
+    }
+
   private:
     /// Internal function for adding a flag
     Option *_add_flag_internal(std::string flag_name, CLI::callback_t fun, std::string flag_description) {
@@ -1345,6 +1387,11 @@ class App {
             return e.get_exit_code();
         }
 
+        if(dynamic_cast<const CLI::CallForVersion *>(&e) != nullptr) {
+            out << e.what() << std::endl;
+            return e.get_exit_code();
+        }
+
         if(e.get_exit_code() != static_cast<int>(ExitCodes::Success)) {
             if(failure_message_)
                 err << failure_message_(this, e) << std::flush;
@@ -1530,6 +1577,23 @@ class App {
         return formatter_->make_help(this, prev, mode);
     }
 
+    /// Displays a version string
+    std::string version() const {
+        std::string val;
+        if(version_ptr_ != nullptr) {
+            auto rv = version_ptr_->results();
+            version_ptr_->clear();
+            version_ptr_->add_result("true");
+            try {
+                version_ptr_->run_callback();
+            } catch(const CLI::CallForVersion &cfv) {
+                val = cfv.what();
+            }
+            version_ptr_->clear();
+            version_ptr_->add_result(rv);
+        }
+        return val;
+    }
     ///@}
     /// @name Getters
     ///@{
@@ -1726,6 +1790,12 @@ class App {
     /// Get a pointer to the config option. (const)
     const Option *get_config_ptr() const { return config_ptr_; }
 
+    /// Get a pointer to the version option.
+    Option *get_version_ptr() { return version_ptr_; }
+
+    /// Get a pointer to the version option. (const)
+    const Option *get_version_ptr() const { return version_ptr_; }
+
     /// Get the parent of this subcommand (or nullptr if master app)
     App *get_parent() { return parent_; }
 

include/CLI/Error.hpp

@@ -157,18 +157,25 @@ class Success : public ParseError {
 };
 
 /// -h or --help on command line
-class CallForHelp : public ParseError {
-    CLI11_ERROR_DEF(ParseError, CallForHelp)
+class CallForHelp : public Success {
+    CLI11_ERROR_DEF(Success, CallForHelp)
     CallForHelp() : CallForHelp("This should be caught in your main function, see examples", ExitCodes::Success) {}
 };
 
 /// Usually something like --help-all on command line
-class CallForAllHelp : public ParseError {
-    CLI11_ERROR_DEF(ParseError, CallForAllHelp)
+class CallForAllHelp : public Success {
+    CLI11_ERROR_DEF(Success, CallForAllHelp)
     CallForAllHelp()
         : CallForAllHelp("This should be caught in your main function, see examples", ExitCodes::Success) {}
 };
 
+/// -v or --version on command line
+class CallForVersion : public Success {
+    CLI11_ERROR_DEF(Success, CallForVersion)
+    CallForVersion()
+        : CallForVersion("This should be caught in your main function, see examples", ExitCodes::Success) {}
+};
+
 /// Does not output a diagnostic in CLI11_PARSE, but allows to return from main() with a specific error code.
 class RuntimeError : public ParseError {
     CLI11_ERROR_DEF(ParseError, RuntimeError)

include/CLI/StringTools.hpp

@@ -190,7 +190,7 @@ inline bool valid_name_string(const std::string &str) {
     return true;
 }
 
-/// check if a string is a container segment separator (empty or "%%"
+/// check if a string is a container segment separator (empty or "%%")
 inline bool is_separator(const std::string &str) {
     static const std::string sep("%%");
     return (str.empty() || str == sep);

include/CLI/TypeTools.hpp

@@ -232,7 +232,7 @@ struct is_mutable_container<
 // check to see if an object is a mutable container (fail by default)
 template <typename T, typename _ = void> struct is_readable_container : std::false_type {};
 
-/// type trait to test if a type is a container meaning it has a value_type, it has an iterator, a clear, and an en end
+/// type trait to test if a type is a container meaning it has a value_type, it has an iterator, a clear, and an end
 /// methods and an insert function.  And for our purposes we exclude std::string and types that can be constructed from
 /// a std::string
 template <typename T>
@@ -244,7 +244,7 @@ struct is_readable_container<
 // check to see if an object is a wrapper (fail by default)
 template <typename T, typename _ = void> struct is_wrapper : std::false_type {};
 
-// check if an object is a is a wrapper (it has a value_type defined)
+// check if an object is a wrapper (it has a value_type defined)
 template <typename T>
 struct is_wrapper<T, conditional_t<false, void_t<typename T::value_type>, void>> : public std::true_type {};
 
@@ -344,7 +344,7 @@ auto value_string(const T &value) -> decltype(to_string(value)) {
     return to_string(value);
 }
 
-/// temple to get the underlying value type if it exists or use a default
+/// template to get the underlying value type if it exists or use a default
 template <typename T, typename def, typename Enable = void> struct wrapped_type { using type = def; };
 
 /// Type size for regular object types that do not look like a tuple

tests/HelpTest.cpp

@@ -1165,3 +1165,53 @@ TEST(THelp, FunctionDefaultString) {
 
     EXPECT_THAT(help, HasSubstr("INT=Powerful"));
 }
+
+TEST(TVersion, simple_flag) {
+
+    CLI::App app;
+
+    app.set_version_flag("-v,--version", "VERSION " CLI11_VERSION);
+
+    auto vers = app.version();
+    EXPECT_THAT(vers, HasSubstr("VERSION"));
+
+    app.set_version_flag();
+    EXPECT_TRUE(app.version().empty());
+}
+
+TEST(TVersion, callback_flag) {
+
+    CLI::App app;
+
+    app.set_version_flag("-v,--version", []() { return std::string("VERSION " CLI11_VERSION); });
+
+    auto vers = app.version();
+    EXPECT_THAT(vers, HasSubstr("VERSION"));
+
+    app.set_version_flag("-v", []() { return std::string("VERSION2 " CLI11_VERSION); });
+    vers = app.version();
+    EXPECT_THAT(vers, HasSubstr("VERSION"));
+}
+
+TEST(TVersion, parse_throw) {
+
+    CLI::App app;
+
+    app.set_version_flag("--version", CLI11_VERSION);
+
+    EXPECT_THROW(app.parse("--version"), CLI::CallForVersion);
+    EXPECT_THROW(app.parse("--version --arg2 5"), CLI::CallForVersion);
+
+    auto ptr = app.get_version_ptr();
+
+    ptr->ignore_case();
+    try {
+        app.parse("--Version");
+    } catch(const CLI::CallForVersion &v) {
+        EXPECT_STREQ(v.what(), CLI11_VERSION);
+        EXPECT_EQ(v.get_exit_code(), 0);
+        const auto &appc = app;
+        auto cptr = appc.get_version_ptr();
+        EXPECT_EQ(cptr->count(), 1U);
+    }
+}