On 1/31/22 2:46 PM, Will Senn wrote:

All,

I have been doing some language exploration in v7/4.3bsd and came across Software Tools (not the pascal version). It's written using ratfor, which I had seen in the v7 UPM. I fired up v7 and tried my hand at the first example:

I thought I'd close the loop on the language side of this thread. I am happy to report that ratfor (and fortran) is alive and well. It works on my mac! The Software Tools book is awesome, if challenging. The first chapter is particularly challenging as it takes a bit to figure out where the authors are coming from and what they include, exclude, and highlight... and why. The key to understanding the book, as a modern reader, is to understand that the authors assume their readers are fortran (or PL/I) programmers. Because of this, they don't explain anything that would be obvious to said programmers (read, write, LUNs, Hollerith cards, format, etc). In addition, they will push down details of implementation until they practically disappear (think singularity... annoyingly consistent in this regard). When they say something like "EOF is a symbolic constant... We won't tell you what its value is, since the particular value doesn't matter", they really mean it. Unfortunately, in order to actually implement stuff, you gotta know what every symbolic constant and macro replacement is :).

For example, even in the tiny copy program example, from the introductory chapter, once you include the primitive getc and putc subroutines, there are 7 symbolic constants: MAXLINE, MAXCARD, NEWLINE, STDIN, STDOUT, EOF, SPACE and character, which is really an integer and gets replaced with integer by some mythical preprocessor (chapter 8). Anyhow, in the modern world, MAXLINE and MAXCARD don't really have meaning, but they can magically be treated as lines of a file, the rest do have meaning, but they don't evaluate to the same things in Fortran-land as in modern-land. STDIN is 5 and STDOUT is 6 (card reader and punch LUNs, again some magic that lets them be treated as terminal input and output), EOF is -1, SPACE is 32, NEWLINE is 10. Anyhow, long story just a bit shorter, replace those constants, swap character for integer, and combine getc, putc, and copy and yahoo, a working copy program that works in v7, 4.xBSD, and Mac OS X Mojave (and BSD, etc), without any further modifications... at all.

Included for the curioius (copynew.r):

# on v7
# $ ratfor -C copynew.r > copynew.f
# $ f77 -o copynew copynew.f
# on mac
# $ ratfor77 -C copynew.r > copynew.f
# $ gfortran -o copynew copynew.f
# $ ./copynew
# This is a test.
# This is a test.
# CTRL-d
# $

# getc (simple version) - get characters from standard input
        integer function getc(c)
        integer buf(81), c
        integer i, lastc
        data lastc /81/,buf(81) /10/

        lastc = lastc + 1
        if(lastc > 81) {
                read(5, 100, end=10) (buf(i), i = 1, 80)
                        100 format(80 a 1)
                lastc = 1
                }
        c = buf(lastc)
        getc = c
        return

10      c = -1
        getc = -1
        return
        end

# putc (simple version) - put characters on the standard output
        subroutine putc(c)
        integer buf(80), c
        integer i, lastc
        data lastc /0/

        if (lastc > 80 | c == 10) {
                for (i = lastc + 1; i <= 80; i = i + 1)
                        buf(i) = 32
                write(6, 100) (buf(i), i = 1, 80)
                        100 format(80 a 1)
                lastc = 0
                }
        if (c != 10) {
                lastc = lastc + 1
                buf(lastc) = c
                }
        return
        end

# copy - copy input characters to output
        integer getc
        integer c

        while(getc(c) != -1)
                call putc(c)
        stop
        end

Of course, it's criminal to have all those hardcoded magic numbers, wouldn't it be swell if there were some sort of macro facility?... oh, wait, that's what Chapter 8's all about... I can't wait.

Will