bash
cargo install -f fsm_gen
You can download from repository and build and install as usual
bash
cargo build --release
cargo install
namespace for functionsUpdate idata in order to use ispush with btrees and more
Complete the cpp example and update on README.md
output with signals
Add languages
All computing processes consist of receiving an input and processing it by generating an output. From the simplest to the most complex.
Sometimes, the process depends on the context and it is necessary to manage a state.
Messages and state management, therefore, are two fundamental elements of any software process.
That's why I wrote two external DSLs long time ago for both elements (which I still use in production and are a great help).
In this repository I rewrite one of them, the code generator for a state machine.
At the moment it generates C++ code (my most immediate target in production).
You can have data (fields) on inputs structs, and also on each status
To explain the system, I will use the example in cpp_test/fsm
This example is about writing a system that will handle login requests.
First the server will be asked for a password.
This key will be used to encode the username and password (this one will be passed through a hash function) in the login request.
This encoding will be irreversible (hash function). The server will perform the same operation (starting from the hash of the password) to verify the validity.
If it is OK, it will send a login confirmation.
The diagram would look like this:
A list of transitions could be written as:
```peg // Example of fsm to manage login // on server side
[init] rqkey -> wlogin / send_key timer -> init _ -> error // any other input...
[wlogin] rqlogin & valid -> login / sendlogin rqlogin -> error timer & timeout -> error timer -> w_login _ -> error
[login] rqlogout -> logout / sendlogout heartbeat -> login / update_hb timer & timeout -> logout timer -> login _ -> error
[logout] timer -> logout _ -> error
[error] _ -> error ```
And this is the input for this tool to generate code
In fact, even the previous diagram has been generated from this DSL (it generated a graphviz dot file)
peg
[init]
...
init, w_login, login ... are the states
Depending on the input and the state (with its values as will be seen later), the system will change to a new state.
peg
rq_key -> w_login
If we receive an input (in this case rq_key) we go to next state (w_login)
The elements received by the status machine.
peg
INPUT
v
rq_key -> w_login
In the example they are rqkey, rqlogin, rq_logout, heartbeat and timer.
Functions that will be called depending on the status and input to decide the way forward.
peg
GUARD
v
rq_login & valid -> login / send_login
In the example we have valid, timeout, ontime.
All transitions can be replicated with different guards, but always one of them has to be without guard (and the last one). Example:
peg
rq_login & valid -> login / send_login
rq_login -> logout / log_err
Behind the -> arrow is the state we will change to.
peg
FINAL_STATUS
v
rq_key -> w_login
We can define an action to be performed when executing a transaction.
This will be after the final state and '/'.
peg
ACTION
v
rq_login -> logout / log_err
In this example we have sendkey, sendlogin...
In all states it is necessary to consider all inputs.
But it is very common that many transitions are the same (generally error cases).
This is marked with the input _
Consider the init status:
peg
[init]
rq_key -> w_login / send_key
timer -> init
_ -> logout / log_err
_ will be expanded to produce...
peg
[init]
rq_key -> w_login / send_key
timer -> init
rq_login -> logout / log_err
heartbeat -> logout / log_err
rq_logout -> logout / log_err
Therefore considering all possible inputs in this state
Comments starts at // and continues to the end of line
To get help...
bash
fsm_gen --help
```txt fsm_gen 0.2.0 jleahred
Generate code from a simple fsm file
To check the supported languages --show_langs
USAGE: fsmgen [FLAGS] [OPTIONS] [fsmfiles]...
FLAGS: -d, --dot-graphviz Generate graphviz dot file -h, --help Prints help information --help-cpp Give me some information about generating cpp files -s, --show-langs Show supported languages generators -V, --version Prints version information
OPTIONS:
-l, --lang
ARGS:
The default language is c++ (and at the moment the only one)
You can run:
bash
fsm_gen login.fsm
And it will generate the c++
You can pass a list of fsm files
bash
fsm_gen login.fsm test/seller.fsm test/test2/lift.fsm
The code will be generated on same directory of original .fsm file
If your shell supports it, you could run...
bash
fsm_gen **/*.fsm
Starting from the example login.fsm the system will create...
txt
fsm_login_gen.h
fsm_login_gen.cpp
You don't have to modify these files.
You have to write your code on next files...
txt
fsm_login_types.h
fsm_login_private.hpp
These two files will be created if don't exist as a reference
A empty reference code for these two files will be added on _gen files as comments.
Files dependency:
Full code on cpptest/fsm/fsmlogin_gen.h
We are informed on when it was created.
This file is the starting point to use or extend the generated status machine in your program.
cpp
// generated automatically 2019-03-22 11:24:40
// do not modify it manually
Headers and namespaces based on filename
```cpp
namespace login { ```
Internal class forward declaration
cpp
class BaseState;
typedef std::shared_ptr<BaseState> SState;
The fsm class you have to instantiate or extend
```cpp // ------------------- // F S M class Fsm { public: Fsm(); ~Fsm();
void in(const heartbeatt& in); void in(const rqkeyt& in); void in(const rqlogint& in); void in(const rqlogoutt& in); void in(const timert& in);
... } ```
Full code on cpptest/fsm/fsmlogin_gen.cpp
You must not modify this file, and it's not necessary to know much about it
Full code on cpptest/fsm/fsmlogin_types.h
In this file you have to declare the status info types, and input types
If the file doesn't exist, it will be created with empty data types
cpp
// Code generated automatically to be filled manually
// This file will not be updated by generator
// It's created just the first time as a reference
On namespace based on fsm file, we have the two types to declare
You can, of course, complete these types on cpp file if necessary
```cpp namespace login {
// status info types struct stinitt{}; struct stwlogint{}; struct stlogint{}; struct stlogoutt{}; struct sterror_t{};
// input types struct inheartbeatt {}; struct inrqkeyt {}; struct inrqlogint {}; struct inrqlogoutt {}; struct intimer_t {};
} // namespace login
```
Full code on cpptest/fsm/fsmlogin_private.hpp
This is the other file you have to maintain by hand.
```cpp
// Code generated automatically to be filled manually // This file will not be updated by generator // It's created just the first time as a reference
// This file will be included in _gen.cpp // (anywhere else)
// to make happy some IDEs
namespace { using namespace login; ```
As you can see, it is on anonymous namespace.
This file is private, it will be included by _gen.cpp. Defining an anonymous
namespace, we keep this implementation as private. Even more important, the compiler
will alert us if we forget an implementation, also if one is not necessary.
Log and status change transitions are templates.
This is a log example:
cfg
[init] rq_key -> w_login
[w_login] rq_login(valid) -> login
[login] rq_logout -> logout
In this way, you can specialize or generalize as much as you want.
```cpp
// log
template
// status change functions
template <typename FROM, typename IN> st_init_t from_in2init(const FROM&, const IN&) { return st_init_t{}; }
template <typename FROM, typename IN> st_w_login_t from_in2w_login(const FROM&, const IN&) { return st_w_login_t{}; }
template <typename FROM, typename IN> st_login_t from_in2login(const FROM&, const IN&) { return st_login_t{}; }
template <typename FROM, typename IN> st_logout_t from_in2logout(const FROM&, const IN&) { return st_logout_t{}; }
template <typename FROM, typename IN> st_error_t from_in2error(const FROM&, const IN&) { return st_error_t{}; }
```
First parameter in log, is an string with transition change information (initial transition, input, guard if so, final transition)
Next, we have the guards and actions functions.
```cpp // guards bool valid(const inrqlogint& /*in*/, const stwlogint& /st_info/) { return true; } bool timeout(const intimert& /in/, const stwlogint& /*stinfo/) { return true; } bool timeout(const in_timer_t& /in/, const st_login_t& /st_info*/) { return true; }
// actions
void act_send_key(const st_init_t& /*st_orig*/, const in_rq_key_t& /*in*/, const st_w_login_t& /*st_dest*/) {}
void act_send_login(const st_w_login_t& /*st_orig*/, const in_rq_login_t& /*in*/, const st_login_t& /*st_dest*/) {}
void act_send_logout(const st_login_t& /*st_orig*/, const in_rq_logout_t& /*in*/, const st_logout_t& /*st_dest*/) {}
void act_update_hb(const st_login_t& /*st_orig*/, const in_heartbeat_t& /*in*/, const st_login_t& /*st_dest*/) {}
} // namespace anonymous ```
```dot digraph G { rankdir = BT; node [shape=plaintext fontname="Arial"];
main -> "fsmlogingen.h"
"fsmlogingen.cpp" -> "fsmlogingen.h"
"fsmlogingen.h" -> "fsmlogintypes.h"
} ```