Fortran II Hypersource
79 points by texdraft 5 days ago | 8 comments
  • sampo 5 days ago |
    FORTRAN II was a version of Fortran in use from 1958 to 1961, then superseded by FORTRAN IV. (IBM never published FORTRAN III, it was only an IBM internal project.)

    https://en.wikipedia.org/wiki/Fortran#FORTRAN_II

  • cide1 5 days ago |
    Its amazing to me how few instructions it took to write this. I would love to see higher level documentation of how it all fits together.
  • fsckboy 5 days ago |
    you buried the lede in the lead, where it links:

    See also LISP 1.5

    https://texdraft.github.io/lisp-1.5/listing.html

    finally! being able to take the actual CAR and CDR!

    • aap_ 5 days ago |
      CAR here and CDR just below: https://texdraft.github.io/lisp-1.5/listing.html#line-7626
      • fsckboy 5 days ago |
        thanks for finding that, i love it!
      • nyrikki 5 days ago |
        For those not familiar with these old IBM machines that used decrementing of the index registers, this will help explain all the ??D instructions are there.

        https://bitsavers.org/pdf/ibm/704/24-6661-2_704_Manual_1955....

        Another lens for the FORTRAN case specifically, in the modern way we tend to say Fortran arrays are 'one' indexed, looking at this old code it is sometimes useful of thinking of it as a limit index, pulling from n-1 -> n. Or at least I found that useful for myself when digging into some of this a long time ago.