Release v1.2.0

CMakeLists.txt

@@ -206,7 +206,7 @@ configure_package_config_file(
 
 write_basic_package_version_file(
     ${CMAKE_CURRENT_BINARY_DIR}/smlConfigVersion.cmake
-    VERSION 1.1.13
+    VERSION 1.2.0
     COMPATIBILITY SameMajorVersion
 )
 

README.md

@@ -287,6 +287,7 @@ send: 42
     * [sm [state machine]](https://boost-ext.github.io/sml/user_guide.html#sm-state-machine)
     * [policies [state machine]](https://boost-ext.github.io/sml/user_guide.html#policies-state-machine)
     * [testing::sm [testing]](https://boost-ext.github.io/sml/user_guide.html#testingsm-testing)
+    * [make_action [utility]](https://boost-ext.github.io/sml/user_guide.html#make_action-utility)
     * [make_dispatch_table [utility]](https://boost-ext.github.io/sml/user_guide.html#make_dispatch_table-utility)
 * [Examples](https://boost-ext.github.io/sml/examples.html)
     * [Hello World](https://boost-ext.github.io/sml/examples.html#hello-world)
@@ -312,7 +313,11 @@ send: 42
     * [SDL2 Integration](https://boost-ext.github.io/sml/examples.html#sdl2-integration)
     * [Plant UML Integration](https://boost-ext.github.io/sml/examples.html#plant-uml-integration)
 * [FAQ](https://boost-ext.github.io/sml/faq.html)
+    * [Limitations](https://boost-ext.github.io/sml/faq.html#limitations)
+    * [`on_entry<_>` across translation units](https://boost-ext.github.io/sml/faq.html#on_entry_-across-translation-units)
+    * [`operator,` with two raw member-function-pointer actions](https://boost-ext.github.io/sml/faq.html#operator-with-two-raw-member-function-pointer-actions)
 * [CHANGELOG](https://boost-ext.github.io/sml/CHANGELOG.html)
+    * [[1.2.0] - 2026-06-01](https://boost-ext.github.io/sml/CHANGELOG.html#120-2026-06-01)
     * [[1.1.13] - 2025-12-01](https://boost-ext.github.io/sml/CHANGELOG.html#1113-2025-12-01)
     * [[1.1.12] - 2025-04-02](https://boost-ext.github.io/sml/CHANGELOG.html#1112-2025-04-02)
     * [[1.1.11] - 2024-03-09](https://boost-ext.github.io/sml/CHANGELOG.html#1111-2024-03-09)

doc/CHANGELOG.md

@@ -1,3 +1,27 @@
+## [1.2.0] - 2026-06-01
+- **Additions**
+    - `sm::flush_queue()` — drain pending queued events from async handlers (#456)
+    - `sml::clear_defer` action — discard deferred events from a transition (#643)
+    - `sml::deps<Ts...>` policy — explicit pool dependencies for generic-lambda actions/guards (#437)
+    - `sml::make_action<Deps...>(f)` — wrap a template/generic/constrained callable so its dependency and event types are deduced from the explicit `<Deps...>` list (#629)
+
+- **Behavior changes**
+    - Empty-SM min-size trick is now OFF by default on GCC/Clang (it was UB at `-O2`);
+      opt back in with `BOOST_SML_CFG_ENABLE_MIN_SIZE`. `sizeof(sm)` for an empty SM may change (#249)
+    - `any`/`_` wildcard no longer fires when a composable sub-SM has terminated (#622)
+    - Events raised via `process(E{})` are now storable in the process queue (#580)
+    - Guard taking `const State&` now sees live pool state instead of a stale copy (#530)
+    - Sub-SM defer queue is cleared when its composite state is re-entered (#253)
+
+- **Bug Fixes**
+    - Template-depth, `-Wshadow`, `-Wextra-semi`, UBSan, final-class, null-deref,
+      double-pop, reserved-identifier and related fixes — see full list:
+    - https://github.com/boost-ext/sml/compare/v1.1.13...v1.2.0
+
+- **Documented limitations**
+    - `on_entry<_>` multi-TU linker limitation and dispatch priority (#565)
+    - `operator,` with two raw member-function-pointer actions; `wrap()` workaround (#389)
+
 ## [1.1.13] - 2025-12-01
 - Changes
     - https://github.com/boost-ext/sml/compare/v1.1.12...v1.1.13

doc/examples.md

@@ -25,66 +25,88 @@
 
 ###Hello World
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/hello_world.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/dq85hW4ab)
 
 ###Events
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/events.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/s816cG5j8)
 
 ###States
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/states.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/c9asGjYTr)
 
 ###Actions Guards
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/actions_guards.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/nehrdofPx)
 
 ###Transitions
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/transitions.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/qr8qs78Ts)
 
 ###Defer/Process
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/defer_and_process.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/T7YaW61en)
 
 ###Orthogonal Regions
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/orthogonal_regions.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/vqGbsrqM3)
 
 ###Composite
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/composite.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/5sYb9eGbe)
 
 ###History
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/history.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/Pvz6Y7vd4)
 
 ###Error handling
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/error_handling.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/cGd7TnM1G)
 
 ###Logging
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/logging.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/Tec7jz36r)
 
 ###Nested
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/nested.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/xd9PoEPdn)
 
 ###Testing
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/testing.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/oc73h5sY8)
 
 ###Runtime Dispatcher
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/dispatch_table.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/j5bMnobY9)
 
 ###eUML Emulation
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/euml_emulation.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/n93Y5Mner)
 
 ###Dependencies
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/dependencies.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/afxWz4jq3)
 
 ###Data
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/data.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/P4vn1dK9e)
 
 ###In-Place
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/in_place.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/r43fKbz6z)
 
 ###Dependency Injection
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/dependency_injection.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/1Pv6EaG7n)
 
 ###Arduino Integration
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/arduino.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/Kfba9GovG)
 
 ###SDL2 Integration
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/sdl2.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/8heY58eE6)
 
 ###Plant UML Integration
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/example/plant_uml.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/8eT6aWsc9)

doc/faq.md

@@ -0,0 +1,31 @@
+# FAQ
+
+## Limitations
+
+### `on_entry<_>` across translation units
+
+When `on_entry<_>` (the wildcard entry handler) is defined in one translation unit
+while the `initial`-event specialization is left undefined, the linker reports an
+undefined reference. Make sure the entry handler is fully defined where it is used.
+
+Dispatch priority: a specific `on_entry<e1>` handler takes priority over the
+`on_entry<_>` wildcard. The wildcard fires only when no specific handler matches the
+event used to enter the state.
+
+```cpp
+// on_entry<e1> fires when entering via e1 (specific handler wins)
+// on_entry<_>  fires when entering via any other event (no specific handler)
+```
+
+### `operator,` with two raw member-function-pointer actions
+
+Two raw member-function-pointer actions combined with the comma operator
+(`&A::f, &A::g`) select the built-in comma operator, because both operands are
+class types — so SML's action-sequencing is bypassed. Wrap the actions with
+`wrap(...)` to restore sequencing:
+
+```cpp
+*"s1"_s + event<e> / (wrap(&A::f), wrap(&A::g)) = X
+```
+
+See `example/actions_guards.cpp` for a worked example.

doc/index.md

@@ -46,9 +46,13 @@ to avoid it `[Boost].SML` may suit you!
 ###Real Life examples?
 
 ![CPP(BTN)](Run_SDL2_Integration_Example|https://raw.githubusercontent.com/boost-ext/sml/master/example/sdl2.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/8heY58eE6)
 ![CPP(BTN)](Run_Plant_UML_Example|https://raw.githubusercontent.com/boost-ext/sml/master/example/plant_uml.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/8eT6aWsc9)
 ![CPP(BTN)](Run_Logging_Example|https://raw.githubusercontent.com/boost-ext/sml/master/example/logging.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/Tec7jz36r)
 ![CPP(BTN)](Run_Testing_Example|https://raw.githubusercontent.com/boost-ext/sml/master/example/testing.cpp)
+[▶ Run on Compiler Explorer](https://godbolt.org/z/oc73h5sY8)
 
  
 

doc/overview.md

@@ -48,7 +48,17 @@ git clone https://github.com/boost-ext/sml && cd sml && make test
 ###Configuration
 | Macro                                                         | Description                                                  |
 | --------------------------------------------------------------|--------------------------------------------------------------|
-| `BOOST_SML_VERSION`                                           | Current version of [Boost].SML (ex. 1'0'0)                |
+| `BOOST_SML_VERSION`                                           | Current version of [Boost].SML (ex. 1'1'13)                |
+| `BOOST_SML_CFG_ENABLE_MIN_SIZE`                               | Opt in to the empty-SM size trick (zero-size array); disabled by default, see note below |
+| `BOOST_SML_CFG_DISABLE_MIN_SIZE`                              | Legacy name kept for backward compatibility; the min-size trick is now disabled by default |
+| `BOOST_SML_DISABLE_EXCEPTIONS`                                | Build with exceptions disabled (e.g. with `-fno-exceptions`) |
+| `BOOST_SML_CREATE_DEFAULT_CONSTRUCTIBLE_DEPS`                 | Allow default-constructing dependencies owned by the State Machine |
+
+> **Note (min-size):** Since the changes after `v1.1.13`, the empty-State-Machine
+> size optimization is **off by default** on GCC/Clang because the zero-length-array
+> trick triggered undefined behavior at `-O2` (UBSan violations). As a result,
+> `sizeof(sm<...>)` for an empty State Machine may differ from earlier releases.
+> Define `BOOST_SML_CFG_ENABLE_MIN_SIZE` to opt back in.
 
 
 ###Exception Safety
@@ -83,15 +93,19 @@ sm.process_event(event{}); // thread safe call
 
 ***Not configurable***
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/test/ft/errors/not_configurable.cpp)
+[▶ See the compile error on Compiler Explorer](https://godbolt.org/z/zehzezMoe)
 
 ***Not callable***
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/test/ft/errors/not_callable.cpp)
+[▶ See the compile error on Compiler Explorer](https://godbolt.org/z/fb8K6q4WK)
 
 ***Not transitional***
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/test/ft/errors/not_transitional.cpp)
+[▶ See the compile error on Compiler Explorer](https://godbolt.org/z/3aWdcTanT)
 
 ***Not dispatchable***
 ![CPP](https://raw.githubusercontent.com/boost-ext/sml/master/test/ft/errors/not_dispatchable.cpp)
+[▶ See the compile error on Compiler Explorer](https://godbolt.org/z/984KoaP6x)
 
 [Boost.MSM-eUML]: http://www.boost.org/doc/libs/1_60_0/libs/msm/doc/HTML/ch03s04.html
 [Boost.MSM3-eUML2]: https://htmlpreview.github.io/?https://raw.githubusercontent.com/boostorg/msm/msm3/doc/HTML/ch03s05.html

doc/scripts/gen_godbolt_links.sh

@@ -0,0 +1,85 @@
+#!/usr/bin/env bash
+#
+# Regenerate the "Run on Compiler Explorer" links embedded in the docs.
+#
+# Boost.SML is a single-header library that is NOT registered as a Compiler
+# Explorer library. Each godbolt.org/z/ link keeps the example source intact and
+# pulls the header via Compiler Explorer's client-side "#include from URL" feature:
+#   #include <https://raw.githubusercontent.com/boost-ext/sml/master/include/boost/sml.hpp>
+# CE fetches and pastes that header in the browser when the link is opened (it is
+# NOT resolved by the compile API). dispatch_table.hpp itself does a relative
+# `#include "boost/sml.hpp"`, which CE's fetcher cannot resolve, so for the two
+# examples that use it (dispatch_table, sdl2) the small utility header is inlined
+# with its own sml.hpp include rewritten to the URL form.
+#
+# The error/* examples intentionally fail to compile and get compile-only links
+# that show the diagnostic.
+#
+# Requirements: bash, curl, jq. Run from the repository root.
+# Usage:
+#   doc/scripts/gen_godbolt_links.sh            # print "name url" for every example
+#   doc/scripts/gen_godbolt_links.sh --insert   # also rewrite the CE links in doc/*.md
+#
+set -euo pipefail
+cd "$(git rev-parse --show-toplevel)"
+
+GCC=g142                      # Compiler Explorer GCC 14.2
+STD_DEFAULT=c++14             # SML's minimum standard
+DT=include/boost/sml/utility/dispatch_table.hpp
+URL='https://raw.githubusercontent.com/boost-ext/sml/master/include/boost/sml.hpp'
+
+assemble() { # <src.cpp>  -> thin url-include source on stdout
+  # Rewrite `#include <boost/sml.hpp>` to the URL form; for the dispatch_table.hpp
+  # include, inline that small header with its own sml.hpp include rewritten too.
+  awk -v url="$URL" -v dt="$DT" '
+    /#include[ \t]*[<"]boost\/sml\.hpp[>"]/ { print "#include <" url ">"; next }
+    /#include[ \t]*[<"]boost\/sml\/utility\/dispatch_table\.hpp[>"]/ {
+        while ((getline l < dt) > 0)
+          if (l ~ /#include[ \t]*[<"]boost\/sml\.hpp[>"]/) print "#include <" url ">"; else print l
+        close(dt); next }
+    { print }
+  ' "$1"
+}
+
+shorten() { # <assembled-file> <std> <execute:true|false> -> godbolt short url
+  local src="$1" std="$2" exec="$3"
+  jq -n --rawfile s "$src" --arg std "$std" --argjson ex "$exec" \
+    '{sessions:[{id:1,language:"c++",source:$s,
+      compilers:[{id:"'"$GCC"'",options:("-O2 -std="+$std),libs:[],
+        filters:{execute:$ex,labels:true,directives:true,commentOnly:true,trim:true,demangle:true}}],
+      executors:(if $ex then [{compiler:{id:"'"$GCC"'",options:("-O2 -std="+$std),libs:[],overrides:[]},
+        arguments:"",stdin:"",compilerOutputVisible:true,stdoutVisible:true,stderrVisible:true}] else [] end)}]}' \
+    | curl -s -X POST 'https://godbolt.org/api/shortener' -H 'Content-Type: application/json' -d @- | jq -r '.url'
+}
+
+MAP=$(mktemp)
+process() { # <src.cpp> <execute:true|false>
+  local ex="$1" exec="$2" name std tmp url
+  name=$(basename "$ex" .cpp)
+  std=$STD_DEFAULT; [ "$name" = arduino ] && std=c++20   # template lambdas
+  tmp=$(mktemp); assemble "$ex" > "$tmp"
+  url=$(shorten "$tmp" "$std" "$exec"); rm -f "$tmp"
+  echo "$name $url" | tee -a "$MAP"
+}
+
+for f in example/*.cpp; do process "$f" true; done
+for f in test/ft/errors/not_*.cpp; do process "$f" false; done
+
+if [ "${1:-}" = "--insert" ]; then
+  # strip previously-generated CE links, then re-insert after each embed.
+  # Only delete a CE link that immediately FOLLOWS an ![CPP] embed, so standalone
+  # links (e.g. the make_action example in the user guide) are preserved.
+  DOCS=(doc/examples.md doc/tutorial.md doc/user_guide.md doc/index.md doc/overview.md)
+  for d in "${DOCS[@]}"; do
+    awk '{ if (prev ~ /!\[CPP/ && $0 ~ /Compiler Explorer\]\(https:\/\/godbolt\.org/) { prev=$0; next } print; prev=$0 }' "$d" > "$d.tmp" && mv "$d.tmp" "$d"
+  done
+  while read -r name url; do
+    case "$name" in
+      not_*) label="▶ See the compile error on Compiler Explorer";;
+      *)     label="▶ Run on Compiler Explorer";;
+    esac
+    for d in "${DOCS[@]}"; do sed -i "\#/${name}\.cpp)#a [$label]($url)" "$d"; done
+  done < "$MAP"
+  echo "docs updated."
+fi
+rm -f "$MAP"

doc/themes/boost-modern/footer.html

@@ -39,5 +39,5 @@
     {% endif %}
   </div>
 
-  Built with <a href="http://www.mkdocs.org">MkDocs</a> using a <a href="https://github.com/snide/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a> | Powered by <a href="http://melpon.org/wandbox">Wandbox</a>
+  Built with <a href="http://www.mkdocs.org">MkDocs</a> using a <a href="https://github.com/snide/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a> | Powered by <a href="https://wandbox.org">Wandbox</a>
 </footer>

doc/themes/boost-modern/js/cpp.js

@@ -48,7 +48,7 @@ function compile_and_run(id) {
     document.getElementById("compile_and_run_" + id).firstChild.data = "Compiling...";
     cpp_output[id].setValue("Compiling...");
     var http = new XMLHttpRequest();
-    http.open("POST", "http://melpon.org/wandbox/api/compile.json", true);
+    http.open("POST", "https://wandbox.org/api/compile.json", true);
     http.onreadystatechange = function(){
         if (http.readyState == 4 && http.status == 200) {
             var output_json = JSON.parse(http.response);
@@ -74,8 +74,11 @@ function compile_and_run(id) {
         , "codes" : [{
               "file" : "boost/sml.hpp"
             , "code" : get_cpp_file("https://raw.githubusercontent.com/boost-ext/sml/master/include/boost/sml.hpp")
+           }, {
+              "file" : "boost/sml/utility/dispatch_table.hpp"
+            , "code" : get_cpp_file("https://raw.githubusercontent.com/boost-ext/sml/master/include/boost/sml/utility/dispatch_table.hpp")
            }]
-         , "options": "warning,cpp-pedantic-errors,optimize,boost-1.60,c++1y"
+         , "options": "warning,cpp-pedantic-errors,optimize,c++1y"
          , "compiler" : "clang-head"
          , "compiler-option-raw": "-I." + "\n" + "-fno-color-diagnostics"
     }));