sml VS Marlin

Anyway the need is not complicated, I need both entry and exit functions from every state, optionally allowing these functions to be coroutines (that's special sauce but for later), and an explicit state transition table which also have a way to say that a state can be accessed at any point. Also allow states to be state machines, optional FSM hierarchies. If you ignore the coroutine stuff it's pretty standard features these days, except that - Boost.MSM is quite archaic now (it was so novel when it was first released...) although it allows most of the features I talked about, I just think it will complicate my code unneecessarilly; - Boost-Ext.SML (not Boost) is almost perfect except it doesnt have entry/exit functions on states for some reason. Also last time we (as in in livestream) tried it in prototypes it didnt compile on msvc XD - Boost-Ext.SML2 is even better but still doesnt have entry/exit functions although it's in the plans.

Hello all. Being a huge fan of state machine and coroutines, I have been browsing around for examples of what other people do combine these two. I have been using boost-ext/sml for quite many projects and are quite happy about that. But when transitioning to code that relies on coroutines, I would like to write entry/exit/actions/guard methods that uses coroutines and where I can co_await on awaitables from Asio and more recently "Boost Async".

boost-ext/sml: quite modern way of doing state machines using a DSL

I recently was troubleshooting a crash that backtraced through the boost::sml library [0]. The crash didn't actually have anything to do with the library, but it was used as the core event loop.

The backtrace -- as in, just the output from running `bt` in GDB -- was over a thousand wrapped lines long. There were ~5 stack frames that took up 200 lines of console each to print just the function name. That product's debug builds recently hit the 2GB line, which is enough that old versions of binutils complain.

I don't know what the solution is. There's some really neat stuff you can do with template metaprogramming, and in stripped release builds it compiles down extremely tiny. Plus the code is very clean to read. But it does feel like there isn't any kind of central vision for the C++ debugging experience, and bad interactions between highly-complex modern C++ typing, the compiler, and the debugger are probably only going to get worse unless somebody (the ISO committee? Vendors?) thinks really hard about debugging support.

[0]: https://github.com/boost-ext/sml

I'm a big fan of MSM but what you're experiencing is pretty normal for template-heavy libraries built on C++03 machinery (emulation of variadic templates is the usual culprit). It's probably not the answer you're hoping for, but the real solution is to switch to a library with more modern foundations. (I've been happily using [Boost::ext].SML for a few years but I'm reluctant to strongly recommend anything in particular since I haven't re-explored the problem space since I found it.)

The Boost one that you mention, seems to be one that it's kinda old. A "successor" of sorts is Boost SML. I've not used it yet, but certainly the first impressions are very good.

Or Boost.Sml

At our company, we rely a lot on https://github.com/boost-ext/sml

I'm a big fan of boost::sml for representing state machines.

https://github.com/boost-ext/sml (State Machine DSL and backend for perfomance)

There is _a lot_ wrong with Marlin. It is a complex codebase, full with ancient artefacts, litterred with preprocessor ifdefs every 2-3 lines of code, dynamic includes in the middle of CPP files, etc[1]. It's about as unreadable as C++ code gets--well, I guess it's not template metaprogramming.

Klipper by contrast is a breeze to read through[2].

I am very grateful for Marlin, for all of reprap, and everyone who has contributed to it. But saying there is nothing wrong with it is straight up misguided.

[1]: https://github.com/MarlinFirmware/Marlin/blob/bugfix-2.1.x/M...

[2]: https://github.com/Klipper3d/klipper/blob/master/src/lcd_hd4...

I think you are mistaken. I can't speak for implementations preceding the Ender 3 V2, so what you're saying may have been true at some point for other machines. However, here you can see Marlin developers confirm that there is an EEPROM on the stock E2V2 board using diagrams from Creality and photographic confirmation. Here is the datasheet for the EEPROM. Here is a thread discussing this Marlin release, and also the then-recent release of official Creality firmware which resolved the same issue. Since the stock firmware is based on Marlin, and at the time Marlin did not support this type of EEPROM, the EEPROM was not usable at launch. Any mainstream firmware (official or third-party) from the last three years will be using the onboard EEPROM unless the user intentionally specified otherwise.

pull latest Marlin from github: https://github.com/MarlinFirmware/Marlin

Also, checked the following discussion but seems like I need to update the firmware to be able to comment that like right? Temperature variance monitor tweaks by zeleps · Pull Request #23571 · MarlinFirmware/Marlin · GitHub

i spent some time and successfully rebased Kobra 2.8.2 OG firmware from an unknown Marlin ~2.0.8 frankenstein to a clean latest (as of now) release (not bugfix) 2.1.x -- v2.1.2.1 + 1 commit

As an example, check the macropocalypse in Marlin - but the actual trigger for me to start was Reprap firmware doing a floating point divide in interrupt context while targeting AVR8 core…

Any change of thermistor or to a PT100/PT1000 will require recompiling the firmware, because every type has different characteristics. Marlin uses an internal table to calculate the temperature for whatever reading it gets from the CPU's analogue-to-digital converter. It has many tables for different thermistors, but only one is ever incorporated at compile time. So you have to specify which type you're using. You can see the commonly-used types in the list in Marlin's Configuration.h file, in the section headed // @section temperature. The tables themselves are in Marlin/src/module/thermistor.

FWIW It IS open source but the GNU General Public License v3.0 rules apply. https://github.com/MarlinFirmware/Marlin/blob/bugfix-2.1.x/LICENSE