Can I set the state inside a function?

Question

I have this code:

procedure EstablishCommunication;
var
    State         : TStates;
    Attempts      : Byte;      
    procedure IncAttempts;
    begin
        Inc(Attempts);
    end;
begin
    State    := stReadDeviceID;
    Attempts := 0;

    while True do
    begin
        if Attempts >= MAX_ATTEMPTS then
        begin
            State := stError;
        end;
        case State of
            stReadDeviceID:
            begin
                // some code
                IncAttempts;
            end;
            stError:
            begin
                // Error code
            end;
        ...
        ...
        ...

I would like to put code that sets state to stError inside the IncAttempts procedure, as a result:

procedure EstablishCommunication;
var
    State         : TStates;
    Attempts      : Byte;      
    procedure IncAttempts;
    begin
        Inc(Attempts);

        if Attempts >= MAX_ATTEMPTS then
        begin
            State := stError;
        end;
    end;
begin
    State    := stReadDeviceID;
    Attempts := 0;

    while True do
    begin            
        case State of
            stReadDeviceID:
            begin
                // some code
                IncAttempts;
            end;
            stError:
            begin
                // Error code
            end;
        ...
        ...
        ...

So, can I move the code to IncAttempts?

Is that the smell of code?

If so, can you advise me the best way?

Answer 1

I would see this as perfect valid code. I ask myself the following questions when declaring a method inside another. In most cases, I do not do this, but sometimes this leads to better code.

• Will the inner function ever change, as in the descendant class?
• Can I override the external method without calling the internal method, and is everything okay?
• ?
• , ?

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Answer 2

, . Attempts, , State . , . /.

Answer 3

, ...

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, , stReadDeviceID.

, while True do - if State = stError then Break;, , stError , . , stError - case -statement ...

GoF, :

• http://en.wikipedia.org/wiki/State_pattern ( Delphi...)
• http://sourcemaking.com/design_patterns/state ( Delphi!)
• http://www.dofactory.com/Patterns/PatternState.aspx ( Delphi...)
• http://conferences.embarcadero.com/article/32129#_Toc12157322 ( Delphi!)