C++ State Machines
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C++ State Machines
1–10 of 29 posts
Re: C++ State Machines
#2Well another OO way would be to add a state member to the Heroine class and create a state class for every possible state (X,Y,Z). Each state can then be responsible for interpreting the input and transitioning to the next appropriate state (if any)
Re: C++ State Machines
#3If you're not willing to develop all the boilerplate code to encode your states, transitions, etc. Boost has two libraries to offer : Boost Statechart and Meta State Machine. One of my favorite question on Stack Overflow compares both: https://stackoverflow.com/questions/4275602/boost-statechart....
As with most Boost libraries, you're in for some serious headache if you decide to use them (or is it just me?) but it's very rewarding in the end.
Re: C++ State Machines
#4If you're not willing to develop all the boilerplate code to encode your states, transitions, etc. Boost has two libraries to offer : Boost Statechart and Meta State Machine. One of my favorite question on Stack Overflow compares both: https://stackoverflow.com/questions/4275602/boost-statechart... . As with most Boost libraries, you're in for some serious headache if you decide to use them (or is it just me?) but it…
Boost.SML (which is experimental) has garnered a lot of attention lately as a modern take on C++ state machines that can replace both of the options you raised.
https://boost-experimental.github.io/sml/
Unfortunately I haven't seen any compelling real world usage of any of these libraries, and the documentation for SML leaves a lot to be desired.
Re: C++ State Machines
#5Well another OO way would be to add a state member to the Heroine class and create a state class for every possible state (X,Y,Z). Each state can then be responsible for interpreting the input and transitioning to the next appropriate state (if any)
How do you manage combinatorial explosion as states increase?
Re: C++ State Machines
#6Well another OO way would be to add a state member to the Heroine class and create a state class for every possible state (X,Y,Z). Each state can then be responsible for interpreting the input and transitioning to the next appropriate state (if any)
How do you manage combinatorial explosion as states increase?
The proposed state table is hardly more scalable. It's obviously not infinitely scalable but In my proposed way, you only have to specify the cases where a state transition actually occurs.
Re: C++ State Machines
#7Well another OO way would be to add a state member to the Heroine class and create a state class for every possible state (X,Y,Z). Each state can then be responsible for interpreting the input and transitioning to the next appropriate state (if any)
How do you manage combinatorial explosion as states increase?
one possibility is to use hierarchical-state-machines (HSM), which allow (encourage even ?) the decomposition of state-machine into common behavior for reuse across states.
HSM have been there for a while, being proposed in '84 (!) by David Harel under the name 'statecharts'
Re: C++ State Machines
#8There's an excellent book (and associated open source project) on using state machines for reactive systems or embedded systems in general: "Practical UML Statecharts in C/C++, 2nd Edition: Event-Driven Programming for Embedded Systems" by Miro Samek. Here's a link to the site where you can download it from (https://www.state-machine.com/psicc2).
Re: C++ State Machines
#9If you're not willing to develop all the boilerplate code to encode your states, transitions, etc. Boost has two libraries to offer : Boost Statechart and Meta State Machine. One of my favorite question on Stack Overflow compares both: https://stackoverflow.com/questions/4275602/boost-statechart... . As with most Boost libraries, you're in for some serious headache if you decide to use them (or is it just me?) but it…
Boost.SML (which is experimental) has garnered a lot of attention lately as a modern take on C++ state machines that can replace both of the options you raised. https://boost-experimental.github.io/sml/ Unfortunately I haven't seen any compelling real world usage of any of these libraries, and the documentation for SML leaves a lot to be desired.
I have been using SML in production for a little over a year now without issues, mostly for protocol machines.
I agree the documentation is not great though, you kind of have to go over the example code and try to figure things out on your own.
Using embedded data for keeping state (e.g. counters, etc; see https://boost-experimental.github.io/sml/examples/index.html...) along with injecting std::functions to use as actions is pretty powerful.
Here's a basic example I wrote some months ago showing a hierarchical machine (https://gist.github.com/indiosmo/08ab24181770125d5a2448d27f6...).
Also please note my usage is pretty basic as I usually have the same machine ported to C# and Python so I tend to use the smallest subset of functionality supported by all the libraries in each language.
Re: C++ State Machines
#10Simulink, and specifically stateflow, is commonly used in the aerospace industry to graphically create state machines that can be autocoded into high performance C or C++ code. I use simulink and stateflow everyday to create flight control software. I feel like more software engineers should learn how to use graphical coding tools, as IMO it's so much easier to represent complex state machines graphically.
It's a shame that Mathworks is essentially the only game in town though, and their software licenses are fairly expensive.