A Quine in Fortran 90 | Hacker News Reader

A Quine in Fortran 90

medium.com

23 pointsorph4nus12 comments

Great, every language needs a Quine. Here's one we created in Elixir: http://elixirgolf.com/articles/elixir-quine-self-replicating...

Enjoyed the article. It made me pine for the days when I had time to dedicate a day to just play with code.

I may be missing something, but isn't a quine trivial when you use a language that allows for file I/O (which I believe Fortran does have)? Or is the point of the "challenge" to avoid using file I/O?

I could be wrong, as I only learned about the concept of a quine recently. But the way I understand it, it is good enough to simply output it. I suppose you could write to a file as well, but where would you write to? The wikipedia page for a quine has a lot of examples and all of them seem to simply output to stdout, just as I did. I don't think the challenge talks at any point about I/O, so I do think you can use it if you would want to.

I didn't mean that you could output to a file -- I meant that, knowing the name of the file the program is saved to (which is possible using facilities available in many modern languages, not sure about Fortran), you can ingest that file and print out its contents (to STDOUT for example).

It feels like cheating, but it's also probably the easiest way to get a true quine which'll always work even if you modify parts of the code (while retaining the part of the program which ingests and prints out the file's contents).

    #!/usr/bin/env python2.7
    print open(__file__, 'r').read()

Seems like cheating!

I had the same feeling: https://en.wikipedia.org/wiki/Quine_%28computing%29#.22Cheat...

Many years ago, I attempted to cheat this way when writing a JScript quine- but it didn't work because the Windows Scripting Host keeps the source file open while interpreting it, which meant the script couldn't open its own source file because the file was already open in another program!

A proper quine, though, doesn't require input.

A multiquine does require you to give input in order to determine what language to output. Although it will output the current file if no input is giving. More info @ https://en.wikipedia.org/wiki/Quine_(computing)#Multiquines

The definition of a multiquine specifically disallows passing in source code as input, though. The input to a multiquine is strictly for selecting which sub-quine to run, or which output set to calculate, and is not used in any way to influence the calculation of the selected output.

print "(2a, 2('2459093414108622880,2821560280312525352,3180149544576887847,1684956475', a))",2459093414108622880,2821560280312525352,3180149544576887847,1684956475;end

I suppose string handling isn't Fortran's strong point!

Reply on news.ycombinator.com