More Verbiage on Diagrams
I first saw a leaning toward “the use of diagrams as computer instruction” when I learned Pascal. Before Java, some college programs in Computer Science started you out by teaching Pascal. It was half-way between BASIC and C, and easy on the Eye. While leaning Pascal it was explained to me that the assignment operator ‘:=’ was a (sort of) left facing arrow (although somewhat mangled). There are some roots in other languages that used ‘<=’ for assignment, but it collided with the “less than or equal” comparison operator, so it was morphed into ‘:=’ . This did a good job of illustrating the action of the assignment operator, (i.e. a value is copied from one variable to the other in the direction of the arrow). Given only a keyboard, the best way to draw a left facing arrow is to use the “<” sign. It was still the day of text-only based computer interaction (the cheaper computers anyway), so there were relatively few graphics on screen, but there was a desire to make graphic elements using the lowly “character.” not quite ASCII art, but a hint of a visual element.
Programming still uses ASCII based graphic to show the meaning of the operator, for instance the PHP object reference notation is a right facing arrow made-up of the characters ‘->’, Coffee script has thin rocket “->” and thick rocket “=>.”, and C has always had the bit wise shift operators ‘>>’ and ‘<<’ to slide bits around. Matching brackets are in relative abundance on the keyboard and are graphical elements in character guise. The left and right parentheses ‘( , )’ are really just a way to draw a circle around something and the square brackets ‘[ , ]‘, a box.
This leads me to the use of diagrams as computer instruction, unlimited graphic elements used (along with text) as the source code for application, To Be Continued…
