[ragel-users] Using Ragel for state machine

[Adrian Thurston]

You're going to have trouble using that recursive style. A ragel state 
machine definition represents a set of states that is substituted in 
place where it is referenced. This precludes recursive definitions.

Another way to look at the problem is to note that regular languages do 
not support recursion, and ragel (at the core) is a means of defining 
regular languages.

It looks like you can rearrange this grammar without recursion to 
something like:

main := ( pressUser+ insertUsb removeUsb )*;

-Adrian

Neil Webster wrote:
> Hi,
> 
> Is it possible to generate a state machine from the code below? I am
> getting stuck with using engines before they have been defined and as
> far as I can figure out, no matter how I order things this will still
> happen.
> 
> %%{
> 
>   machine adcpState ;
> 
>   pressUser = 1;
>   insertUsb = 2;
>   removeUsb = 3;
>         
>   Idle = pressUser Recording ;
> 
>   MassStorage = removeUsb Idle ;
> 
>   Recording = pressUser Idle
>              | insertUsb MassStorage
>              ;
> 
>   main := Idle ;
> 
>   write data;
> 
> }%%
> 
> 
> 
> 
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