feat: support for Atomic types in flags and options (#520)

include/CLI/App.hpp

@@ -789,7 +789,8 @@ class App {
     /// Add option for flag with integer result - defaults to allowing multiple passings, but can be forced to one
     /// if `multi_option_policy(CLI::MultiOptionPolicy::Throw)` is used.
     template <typename T,
-              enable_if_t<std::is_integral<T>::value && !is_bool<T>::value, detail::enabler> = detail::dummy>
+              enable_if_t<std::is_constructible<T, std::int64_t>::value && !is_bool<T>::value, detail::enabler> =
+                  detail::dummy>
     Option *add_flag(std::string flag_name,
                      T &flag_count,  ///< A variable holding the count
                      std::string flag_description = "") {
@@ -810,7 +811,7 @@ class App {
     /// that can be converted from a string
     template <typename T,
               enable_if_t<!detail::is_mutable_container<T>::value && !std::is_const<T>::value &&
-                              (!std::is_integral<T>::value || is_bool<T>::value) &&
+                              (!std::is_constructible<T, std::int64_t>::value || is_bool<T>::value) &&
                               !std::is_constructible<std::function<void(int)>, T>::value,
                           detail::enabler> = detail::dummy>
     Option *add_flag(std::string flag_name,
@@ -824,9 +825,9 @@ class App {
     }
 
     /// Vector version to capture multiple flags.
-    template <
-        typename T,
-        enable_if_t<!std::is_assignable<std::function<void(std::int64_t)>, T>::value, detail::enabler> = detail::dummy>
+    template <typename T,
+              enable_if_t<!std::is_assignable<std::function<void(std::int64_t)> &, T>::value, detail::enabler> =
+                  detail::dummy>
     Option *add_flag(std::string flag_name,
                      std::vector<T> &flag_results,  ///< A vector of values with the flag results
                      std::string flag_description = "") {

include/CLI/TypeTools.hpp

@@ -964,7 +964,22 @@ bool lexical_cast(const std::string &input, T &output) {
 
 /// wrapper types
 template <typename T,
-          enable_if_t<classify_object<T>::value == object_category::wrapper_value, detail::enabler> = detail::dummy>
+          enable_if_t<classify_object<T>::value == object_category::wrapper_value &&
+                          std::is_assignable<T &, typename T::value_type>::value,
+                      detail::enabler> = detail::dummy>
+bool lexical_cast(const std::string &input, T &output) {
+    typename T::value_type val;
+    if(lexical_cast(input, val)) {
+        output = val;
+        return true;
+    }
+    return from_stream(input, output);
+}
+
+template <typename T,
+          enable_if_t<classify_object<T>::value == object_category::wrapper_value &&
+                          !std::is_assignable<T &, typename T::value_type>::value && std::is_assignable<T &, T>::value,
+                      detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     typename T::value_type val;
     if(lexical_cast(input, val)) {
@@ -1019,8 +1034,36 @@ bool lexical_cast(const std::string &input, T &output) {
     return from_stream(input, output);
 }
 
+/// Non-string convertible from an int
+template <typename T,
+          enable_if_t<classify_object<T>::value == object_category::other && std::is_assignable<T &, int>::value,
+                      detail::enabler> = detail::dummy>
+bool lexical_cast(const std::string &input, T &output) {
+    int val;
+    if(integral_conversion(input, val)) {
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4800)
+#endif
+        // with Atomic<XX> this could produce a warning due to the conversion but if atomic gets here it is an old style
+        // so will most likely still work
+        output = val;
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+        return true;
+    }
+    // LCOV_EXCL_START
+    // This version of cast is only used for odd cases in an older compilers the fail over
+    // from_stream is tested elsewhere an not relevent for coverage here
+    return from_stream(input, output);
+    // LCOV_EXCL_STOP
+}
+
 /// Non-string parsable by a stream
-template <typename T, enable_if_t<classify_object<T>::value == object_category::other, detail::enabler> = detail::dummy>
+template <typename T,
+          enable_if_t<classify_object<T>::value == object_category::other && !std::is_assignable<T &, int>::value,
+                      detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     static_assert(is_istreamable<T>::value,
                   "option object type must have a lexical cast overload or streaming input operator(>>) defined, if it "
@@ -1043,7 +1086,7 @@ bool lexical_assign(const std::string &input, AssignTo &output) {
 /// Assign a value through lexical cast operations
 template <typename AssignTo,
           typename ConvertTo,
-          enable_if_t<std::is_same<AssignTo, ConvertTo>::value &&
+          enable_if_t<std::is_same<AssignTo, ConvertTo>::value && std::is_assignable<AssignTo &, AssignTo>::value &&
                           classify_object<AssignTo>::value != object_category::string_assignable &&
                           classify_object<AssignTo>::value != object_category::string_constructible,
                       detail::enabler> = detail::dummy>
@@ -1052,9 +1095,46 @@ bool lexical_assign(const std::string &input, AssignTo &output) {
         output = AssignTo{};
         return true;
     }
+
     return lexical_cast(input, output);
 }
 
+/// Assign a value through lexical cast operations
+template <typename AssignTo,
+          typename ConvertTo,
+          enable_if_t<std::is_same<AssignTo, ConvertTo>::value && !std::is_assignable<AssignTo &, AssignTo>::value &&
+                          classify_object<AssignTo>::value == object_category::wrapper_value,
+                      detail::enabler> = detail::dummy>
+bool lexical_assign(const std::string &input, AssignTo &output) {
+    if(input.empty()) {
+        typename AssignTo::value_type emptyVal{};
+        output = emptyVal;
+        return true;
+    }
+    return lexical_cast(input, output);
+}
+
+/// Assign a value through lexical cast operations for int compatible values
+/// mainly for atomic operations on some compilers
+template <typename AssignTo,
+          typename ConvertTo,
+          enable_if_t<std::is_same<AssignTo, ConvertTo>::value && !std::is_assignable<AssignTo &, AssignTo>::value &&
+                          classify_object<AssignTo>::value != object_category::wrapper_value &&
+                          std::is_assignable<AssignTo &, int>::value,
+                      detail::enabler> = detail::dummy>
+bool lexical_assign(const std::string &input, AssignTo &output) {
+    if(input.empty()) {
+        output = 0;
+        return true;
+    }
+    int val;
+    if(lexical_cast(input, val)) {
+        output = val;
+        return true;
+    }
+    return false;
+}
+
 /// Assign a value converted from a string in lexical cast to the output value directly
 template <typename AssignTo,
           typename ConvertTo,
@@ -1366,10 +1446,11 @@ bool lexical_conversion(const std::vector<std ::string> &strings, AssignTo &outp
 }
 
 /// conversion for wrapper types
-template <
-    typename AssignTo,
-    class ConvertTo,
-    enable_if_t<classify_object<ConvertTo>::value == object_category::wrapper_value, detail::enabler> = detail::dummy>
+template <typename AssignTo,
+          class ConvertTo,
+          enable_if_t<classify_object<ConvertTo>::value == object_category::wrapper_value &&
+                          std::is_assignable<ConvertTo &, ConvertTo>::value,
+                      detail::enabler> = detail::dummy>
 bool lexical_conversion(const std::vector<std::string> &strings, AssignTo &output) {
     if(strings.empty() || strings.front().empty()) {
         output = ConvertTo{};
@@ -1383,6 +1464,26 @@ bool lexical_conversion(const std::vector<std::string> &strings, AssignTo &outpu
     return false;
 }
 
+/// conversion for wrapper types
+template <typename AssignTo,
+          class ConvertTo,
+          enable_if_t<classify_object<ConvertTo>::value == object_category::wrapper_value &&
+                          !std::is_assignable<AssignTo &, ConvertTo>::value,
+                      detail::enabler> = detail::dummy>
+bool lexical_conversion(const std::vector<std::string> &strings, AssignTo &output) {
+    using ConvertType = typename ConvertTo::value_type;
+    if(strings.empty() || strings.front().empty()) {
+        output = ConvertType{};
+        return true;
+    }
+    ConvertType val;
+    if(lexical_conversion<typename ConvertTo::value_type, typename ConvertTo::value_type>(strings, val)) {
+        output = val;
+        return true;
+    }
+    return false;
+}
+
 /// Sum a vector of flag representations
 /// The flag vector produces a series of strings in a vector,  simple true is represented by a "1",  simple false is
 /// by
@@ -1411,5 +1512,32 @@ void sum_flag_vector(const std::vector<std::string> &flags, T &output) {
     output = static_cast<T>(count);
 }
 
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4800)
+#endif
+// with Atomic<XX> this could produce a warning due to the conversion but if atomic gets here it is an old style so will
+// most likely still work
+
+/// Sum a vector of flag representations
+/// The flag vector produces a series of strings in a vector,  simple true is represented by a "1",  simple false is
+/// by
+/// "-1" an if numbers are passed by some fashion they are captured as well so the function just checks for the most
+/// common true and false strings then uses stoll to convert the rest for summing
+template <typename T,
+          enable_if_t<!std::is_signed<T>::value && !std::is_unsigned<T>::value, detail::enabler> = detail::dummy>
+void sum_flag_vector(const std::vector<std::string> &flags, T &output) {
+    std::int64_t count{0};
+    for(auto &flag : flags) {
+        count += detail::to_flag_value(flag);
+    }
+    std::string out = detail::to_string(count);
+    lexical_cast(out, output);
+}
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 }  // namespace detail
 }  // namespace CLI

tests/HelpersTest.cpp

@@ -7,6 +7,7 @@
 #include "app_helper.hpp"
 
 #include <array>
+#include <atomic>
 #include <climits>
 #include <complex>
 #include <cstdint>
@@ -991,6 +992,8 @@ TEST(Types, TypeName) {
     EXPECT_EQ("ENUM", enum_name2);
     std::string umapName = CLI::detail::type_name<std::unordered_map<int, std::tuple<std::string, double>>>();
     EXPECT_EQ("[INT,[TEXT,FLOAT]]", umapName);
+
+    vclass = CLI::detail::classify_object<std::atomic<int>>::value;
 }
 
 TEST(Types, OverflowSmall) {

tests/OptionTypeTest.cpp

@@ -5,6 +5,7 @@
 // SPDX-License-Identifier: BSD-3-Clause
 
 #include "app_helper.hpp"
+#include <atomic>
 #include <complex>
 #include <cstdint>
 #include <cstdlib>
@@ -141,6 +142,33 @@ TEST_F(TApp, BoolAndIntFlags) {
     EXPECT_EQ((unsigned int)2, uflag);
 }
 
+TEST_F(TApp, atomic_bool_flags) {
+
+    std::atomic<bool> bflag{false};
+    std::atomic<int> iflag{0};
+
+    app.add_flag("-b", bflag);
+    app.add_flag("-i,--int", iflag);
+
+    args = {"-b", "-i"};
+    run();
+    EXPECT_TRUE(bflag.load());
+    EXPECT_EQ(1, iflag.load());
+
+    args = {"-b", "-b"};
+    ASSERT_NO_THROW(run());
+    EXPECT_TRUE(bflag.load());
+
+    bflag = false;
+
+    args = {"-iii"};
+    run();
+    EXPECT_FALSE(bflag.load());
+    EXPECT_EQ(3, iflag.load());
+    args = {"--int=notanumber"};
+    EXPECT_THROW(run(), CLI::ConversionError);
+}
+
 TEST_F(TApp, BoolOption) {
     bool bflag{false};
     app.add_option("-b", bflag);
@@ -167,6 +195,26 @@ TEST_F(TApp, BoolOption) {
     EXPECT_FALSE(bflag);
 }
 
+TEST_F(TApp, atomic_int_option) {
+    std::atomic<int> i{0};
+    auto aopt = app.add_option("-i,--int", i);
+    args = {"-i4"};
+    run();
+    EXPECT_EQ(1u, app.count("--int"));
+    EXPECT_EQ(1u, app.count("-i"));
+    EXPECT_EQ(i, 4);
+    EXPECT_EQ(app["-i"]->as<std::string>(), "4");
+    EXPECT_EQ(app["--int"]->as<double>(), 4.0);
+
+    args = {"--int", "notAnInt"};
+    EXPECT_THROW(run(), CLI::ConversionError);
+
+    aopt->expected(0, 1);
+    args = {"--int"};
+    run();
+    EXPECT_EQ(i, 0);
+}
+
 TEST_F(TApp, CharOption) {
     char c1{'t'};
     app.add_option("-c", c1);