Update docs, deprecate visit_scan_arg

.github/workflows/docs.yml

@@ -60,7 +60,7 @@ jobs:
       - name: Generate docs
         run: |
           cd docs
-          poxy --verbose --git-tags --min-version v2.0.0
+          poxy --verbose --git-tags --min-version v2.0.0 --no-squash-patches
 
       - name: Deploy
         uses: peaceiris/actions-gh-pages@v3

CHANGELOG.md

@@ -1,5 +1,17 @@
 # Changelog
 
+## 4.0.0
+
+_Released 2024-xx-xx_
+
+TODO
+
+## 3.0.2
+
+_Released 2024-xx-xx_
+
+TODO
+
 ## 3.0.1
 
 _Released 2024-06-15_

cmake/dependencies.cmake

@@ -110,7 +110,7 @@ else ()
     FetchContent_Declare(
             fast_float
             GIT_REPOSITORY https://github.com/fastfloat/fast_float.git
-            GIT_TAG v6.1.1
+            GIT_TAG v6.1.6
             GIT_SHALLOW TRUE
     )
 

docs/CMakeLists.txt

@@ -25,6 +25,7 @@ add_custom_command(
         DEPENDS
             "${CMAKE_CURRENT_LIST_DIR}/pages/guide.md"
             "${CMAKE_CURRENT_LIST_DIR}/pages/mainpage.md"
+            "${CMAKE_CURRENT_LIST_DIR}/../CHANGELOG.md"
             "${SCN_ABSOLUTE_PUBLIC_HEADERS}"
         COMMENT "Generating docs"
         VERBATIM)

docs/pages/guide.md

@@ -138,10 +138,10 @@ auto [other_result, i] = scn::scan<int>(result->range(), "{}");
 
 The return type of `->range()` is a view into the range `scn::scan` was given.
 Its type may not be the same as the source range, but its iterator and sentinel types are the same.
-If the range given to `scn::scan` does not model `ranges::borrowed_range`
-(essentially, the returned range would dangle), the returned range is of type `ranges::dangling`.
+If the range given to `scn::scan` does not model `scn::ranges::borrowed_range`
+(essentially, the returned range would dangle), the returned range is of type `scn::ranges::dangling`.
 
-Because the range type returned by `scn::scan` is always a `subrange` over its input,
+Because the range type returned by `scn::scan` is always a `scn::ranges::subrange` over its input,
 it's easy to use `scn::scan` in loops, as long as the input type is a `subrange` to begin with.
 If it's not, consider making it one with `scn::ranges::subrange{your-input-range}`.
 
@@ -284,7 +284,7 @@ template <>
 struct scn::scanner<mytype, char> {
     template <typename ParseContext>
     constexpr auto parse(ParseContext& pctx)
-        -> scan_expected<typename ParseContext::iterator>;
+        -> typename ParseContext::iterator;
 
     template <typename Context>
     auto scan(mytype& val, Context& ctx)
@@ -302,11 +302,14 @@ struct scn::scanner<mytype, char> : scn::scanner<std::string_view, char> {};
 
 // Accept only empty
 template <typename ParseContext>
-constexpr auto parse(ParseContext& pctx) -> scan_expected<typename ParseContext::iterator> {
+constexpr auto parse(ParseContext& pctx) -> typename ParseContext::iterator {
     return pctx.begin();
 }
 \endcode
 
+`parse` can report errors by throwing an exception of type `scn::scan_format_string_error`,
+or by calling the `on_error` member function on the `ParseContext`.
+
 `scan` parses the actual value, using the supplied `Context`.
 The context has a member function, `current`, to get an iterator pointing to the next character in the source range,
 and `range`, to get the entire source range that's still left to scan.

docs/pages/mainpage.md

@@ -9,7 +9,7 @@ The code lives over at GitHub, at https://github.com/eliaskosunen/scnlib.
 
 \code{.cpp}
 #include <scn/scan.h>
-#include <print> // for std::print, C++23
+#include <print> // for std::println, C++23
 
 int main() {
     auto result = scn::scan<int, double>("42, 3.14", "{}, {}");
@@ -23,8 +23,9 @@ int main() {
 
 \section main-about About this documentation
 
-This documentation is for the version 3.0 of the library.
-For version 2.0.3, see https://scnlib.dev/v2.0.3/.
+This documentation is for the version 4.0 of the library.
+For other versions, see the dropdown in the upper right corner of the website.
+See <b><a href="./md_poxy_changelog.html">Changelog</a></b> for more.
 
 An introductory guide to the library can be found at \ref guide "Guide".
 
@@ -71,7 +72,7 @@ Another option would be usage through CMake's `FetchContent` module.
 FetchContent_Declare(
         scn
         GIT_REPOSITORY  https://github.com/eliaskosunen/scnlib
-        GIT_TAG         v3.0.1
+        GIT_TAG         v4.0.0
         GIT_SHALLOW     TRUE
 )
 FetchContent_MakeAvailable(scn)
@@ -83,7 +84,7 @@ target_link_libraries(my_program scn::scn)
 
 \subsection main-deps Dependencies
 
-scnlib internally depends on
+scnlib internally optionally depends on
 <a href="https://github.com/fastfloat/fast_float">fast_float</a>.
 
 By default, the CMake machinery automatically fetches, builds, and links it with `FetchContent`.
@@ -117,8 +118,8 @@ Library dependencies
 <tr>
 <td>fast_float</td>
 <td>`>= 5.0.0`</td>
-<td>✅</td>
-<td>Header only. Downloaded by default with `FetchContent`, controlled with `SCN_USE_EXTERNAL_FAST_FLOAT`.</td>
+<td>⚠️</td>
+<td>Required if `SCN_DISABLE_FAST_FLOAT` is `OFF`.<br>Header only. Downloaded by default with `FetchContent`, controlled with `SCN_USE_EXTERNAL_FAST_FLOAT`.</td>
 </tr>
 
 <tr>
@@ -214,6 +215,14 @@ scnlib configuration options
 <th>Description</th>
 </tr>
 
+<tr>
+<td>`SCN_DISABLE_FAST_FLOAT`</td>
+<td>✅</td>
+<td>✅</td>
+<td>`OFF`</td>
+<td>Disable external dependency on FastFloat.<br>Using `ON` requires standard library support for floating-point `std::from_chars`.<sup>1</sup></td>
+</tr>
+
 <tr>
 <td>`SCN_DISABLE_REGEX`</td>
 <td>✅</td>
@@ -227,7 +236,7 @@ scnlib configuration options
 <td>✅</td>
 <td>⚠️</td>
 <td>`"std"`</td>
-<td>Regular expression backend to use<br>(use integer values on the command line)<br>Values: `"std"=0`, `"Boost"`=1`, `"re2"=2`</td>
+<td>Regular expression backend to use<br> (use integer values on the command line)<br>Values: `"std"=0`, `"Boost"=1`, `"re2"=2`</td>
 </tr>
 
 <tr>
@@ -279,6 +288,9 @@ scnlib configuration options
 </tr>
 </table>
 
+<sup>1</sup>: As on October 2024, `std::from_chars` with floating-point values is supported on libstdc++ v11 and newer,
+and MSVC 19.24 (VS 2019 16.4) or newer. libc++ doesn't provide any support yet.
+
 Below, `ENABLE_FULL` is true, if `SCN_CI` is set in CMake, or scnlib
 is built as the primary project.
 

include/scn/fwd.h

@@ -937,7 +937,7 @@ SCN_GCC_POP
 #define SCN_FWD(x)          static_cast<decltype(x)&&>(x)
 #define SCN_DECLVAL(T)      static_cast<T (*)()>(nullptr)()
 
-#define SCN_BEGIN_NAMESPACE inline namespace v3 {
+#define SCN_BEGIN_NAMESPACE inline namespace v4 {
 #define SCN_END_NAMESPACE   }
 
 /////////////////////////////////////////////////////////////////

include/scn/istream.h

@@ -29,16 +29,14 @@ SCN_BEGIN_NAMESPACE
 
 namespace detail {
 template <typename T, typename CharT, typename Enable = void>
-struct is_streamable_impl : std::false_type {
-};
+struct is_streamable_impl : std::false_type {};
 
 template <typename T, typename CharT>
 struct is_streamable_impl<
     T,
     CharT,
     std::enable_if_t<sizeof(SCN_DECLVAL(std::basic_istream<CharT>&)
-                            << std::declval<T>()) != 0>> : std::true_type {
-};
+                            << std::declval<T>()) != 0>> : std::true_type {};
 
 template <typename CharT>
 struct dummy_context_for_is_streamamble {
@@ -54,8 +52,7 @@ struct is_streamable
                                map(SCN_DECLVAL(T&)))>,
               unscannable&>,
           is_streamable_impl<T, CharT>,
-          std::false_type> {
-};
+          std::false_type> {};
 
 /**
  * Wraps `SourceRange`, and makes it a `std::basic_streambuf`.
@@ -189,16 +186,19 @@ struct basic_istream_scanner {
 
         if (!(stream >> val)) {
             if (stream.eof()) {
-                return unexpected_scan_error(scan_error::end_of_input, "EOF");
+                return detail::unexpected_scan_error(scan_error::end_of_input,
+                                                     "EOF");
             }
             if (SCN_UNLIKELY(stream.bad())) {
-                return unexpected_scan_error(scan_error::invalid_source_state,
-                                             "Bad std::istream after reading");
+                return detail::unexpected_scan_error(
+                    scan_error::invalid_source_state,
+                    "Bad std::istream after reading");
             }
 
             SCN_UNLIKELY_ATTR
-            return unexpected_scan_error(scan_error::invalid_scanned_value,
-                                         "Failed to read with std::istream");
+            return detail::unexpected_scan_error(
+                scan_error::invalid_scanned_value,
+                "Failed to read with std::istream");
         }
 
         if (traits::eq_int_type(streambuf.last_char(), traits::eof())) {