4.52 Step

Execution of the next saved command

Syntax

  st
  st(n)

with:
n is worth

Use

This command allows to execute the next command of the saved command line. It allows to replay step by step interactive commands of a previous proof session.

The saved command line is made up of interactive commands which have been entered during a previous interactive proof (otherwise the command line only contains the command pr (see chapter 4.38 page §)). When one goes to a proof obligation, no commands are processed beforehand. So, the user can replay the previous proof work which has been saved, thanks to the st command, and /or use other interactive commands.

The n parameter allows to apply several saved commands at the same time. Its numerical value allows to apply a specific number of commands. If the number is greater than the number of saved commands, the Step command sends back an error message.

End allows the replay of all the saved interactive commands, from the current position of the saved command.

Example

Given the proof obligation whose saved line is:


 
    Command line :  
        Force(0) &  
          Next  
    Saved line pos 1  
        Force(0) &  
        ar(test.1,Fwd) &  
        dd &  
        dd &  
        ar(test.2,Once) &  
        pr &  
        pr  
 


There are 6 interactive saved commands (ar(test.1,Fwd)  dd  dd  ar(test.2,Once)  pr  pr). We are going to replay them, one after the other.

The indicator Saved line pos 1 shows that the next st command will be command #1, that is to say ar(test.1,Fwd) because Force(0) is only a force indicator.


 
PRI> st  
Next step: ar(test.1,Fwd)  
 


The first saved command will be applied:


 
Starting Apply Rule  
    Command line :  
        Force(0) &  
          ar(test.1,Fwd) &  
            Next  
    Saved line pos 2  
 


The first command ar(test.1,Fwd) has been replayed. The indicator Saved line pos shows that the next command to be made by the stwill be command #2.


 
PRI> st  
Next step: dd  
 


The second saved command is applied:


 
Starting Deduction  
    Command line :  
        Force(0) &  
          ar(test.1,Fwd) &  
            dd &  
              Next  
    Saved line pos 3  
 


It is possible to replay all the commands, up to the last one.


 
PRI> st(End)  
 


The last four saved commands are then executed:


 
Starting Deduction  
Starting Apply Rule  
Starting Prover Call  
Starting Prover Call  
 


The command line obtained is therefore:


 
   Command line :  
        Force(0) &  
          ar(test.1,Fwd) &  
            dd &  
              dd &  
                ar(test.2,Once) &  
                  pr &  
                  pr &  
          Next  
    Saved line pos 7  
 


There are no more commands to be replayed because the position indicator is at number 7, that is to say, it is pointing towards the end of the saved commands.


 
PRI> st  
Nothing to step