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From: Malcolm McLean <malcolm.arthur.mclean@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: Writing own source disk
Date: Tue, 4 Jun 2024 19:45:07 +0100
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On 04/06/2024 14:40, Ben Bacarisse wrote:
> Malcolm McLean <malcolm.arthur.mclean@gmail.com> writes:
> 
>> On 03/06/2024 13:11, Ben Bacarisse wrote:
>>> Malcolm McLean <malcolm.arthur.mclean@gmail.com> writes:
>>>
>>>> On 02/06/2024 23:17, Ben Bacarisse wrote:
>>>>> Malcolm McLean <malcolm.arthur.mclean@gmail.com> writes:
>>>>>
>>>>>> Writing a prgram which writes its own source to standard output is a
>>>>>> standard programming problem. It's called a quine.
>>>>> A quine must also not process any input.
>>>>>
>>>>>> And I have achieved a
>>>>>> quine. But a serious quine. Not contrived special purpose code, but serious
>>>>>> codde which can be used to package up source for real.
>>>>> You XML-producing program may be very useful, but it's not really a
>>>>> quine, serious or otherwise.
>>>>>
>>>>>> And it's completely
>>>>>> portable ANSI C. So of course it can't write output to disk - that is
>>>>>> impossible to achive portably. Instead it writes its own source to standard
>>>>>> output using a simle XML format called FileSystem, which represents the
>>>>>> source tree.
>>>>> That sounds as if the program reads input (but it's not explicitly
>>>>> stated) as well as not producing the program text but some XML
>>>>> representation of the program text.  That would make it not a quine for
>>>>> two reasons.
>>>>> How do you process a source tree in completely portable ANSI C?
>>>
>>>> The FileSystem XML fie is embedded with the program. It is a genuine
>>>> quine. Compile it and see.
>>> No need; I'll take your word for it.
>>>
>>>> It's also a very superior quine, and it spits out images and binaries.
>>> If it's a quine (and I don't doubt you) then is spits out its own source
>>> code.  That can, of course, include source code encodings of images.
>>> I'm not sure why you consider that superior, but that is, after all, a
>>> rather subjective assessment.
>>>
>> It's not therortically interesting from a computer science perspective.
>> You can encode images as source.
>>
>> But from a practical point of view, yes my quine is  massively
>> powerful. Most graphical programs do have images as source. And they just
>> get zipped up into the FileSystem XML file. So any binary data can be
>> included. Easily, Using exactly the same system.
> 
> I'm not getting it.  Why do I want a quine in connection to a graphical
> program?  I want a way to include everything in the distribution, but
> we've had that for ages.  Why is having a program that outputs something
> you already have (by defintion!) of any use?
> 
Because you've got the binary, but not the source. And whilst it is a 
quine, of course it is only a quine when you pass it the -quine option. 
Otherwise it is Space Invaders. But if you nedd to recompile the program 
for a new target, -quine spits out the source.

BabyXFS quines are serious quines, they have a real purpose.

-- 
Check out Basic Algorithms and my other books:
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