Re: Perl Quiz of the Week #24 (Turing Machine simulation)

John J. Trammell wrote:
> On Wed, Sep 15, 2004 at 10:41:14AM -0400, colin.rafferty-/PgpppG8B+R7qynMiXIxWgC/[email protected] wrote:
>> Zed Lopez wrote:

>>> Your program should take two parameters: the filename of a file
>>> containing the state transition instructions, and the tape's initial
>>> contents. The filename is required.    

>>> If an initial value for the tape is specified, the read/write head
>>> begins over the first character of that initial value.  

>> I would change the specification of the program to allow for a third
>> argument which is the head's initial location on the tape.  

>> It's value is any number, positive or negative, which specifies the
>> head's position relative to the first character of the second
>> argument.

> I'd say this is a perfect example of a customization that a user may
> wish to apply, but this should be implemented via command-line options,

I disagree.  I think that without it, you cannot specify any finite
initial state of a turing machine.

And since it is a defaulted third parameter, it follows perfectly.

Anyway, that's how I'm going to implement it, but it's a minor detail.
The interesting part is trying to model an infinite tape.

-- 
Colin