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As the article points out, the big first programming languages, FORTRAN, COBOL, LISP, and Algol each had their own way of doing variable assignment. FORTRAN use
by todd8 9y ago
As the article points out, the big first programming languages, FORTRAN, COBOL, LISP, and Algol each had their own way of doing variable assignment. FORTRAN used "=" and Algol used ":=" the other two languages used commands or functions to set or bind the values of variables.
In the mid 60's, when I started programming, most programs had to be keypunched. (There was paper tape entry and Dartmouth's new timesharing system using BASIC, but these weren't in very widespread use.) Until 1964, the keypunch machine in use (IBM 026) had a very limited character set. This is the reason that FORTRAN, COLBOL, and LISP programs were written in upper case. Even the fastest "super" computer of the time, the CDC 6600, was limited to 6-bit characters and didn't have lower case letters.
Naturally, symbols like "←" or "⇐" weren't available, but even the characters ":" and "<" were not on the 026 keypunch keyboard and so ":=" or "<-" were much harder to punch on a card.
These early hardware limitations influenced the design of the early languages, and the early programmers all became accustomed to using "=" (or rarely ":=" or SET) as assignment even though "⇐" might have been more logical. The designers of subsequent programming languages were themselves programmers of earlier languages so most simply continued the tradition.
- kps 9y ago> Naturally, symbols like "←" or "⇐" weren't available, but even the characters ":" and "<" were not on the 026 keypunch keyboard and so ":=" or "<-" were much harder to punch on a card. This explains why early ALGOL implementations (e.g. Burroughs, the only dwarf who went all in on the language) and dialects (ALGO, JOVIAL, MAD, NELIAC) actually used ‘=’ for assignment. This was perfectly legal according to the language definition, which distinguished between the ‘reference language’, which used ‘:=’, and its ‘hardware representation’, which could be anything. (Naturally there was no portability.)
- mygo 9y agoI feel like this is the best answer. People have to work with what they have. Much in the same way that SNES games look the way that do, even though the designers back then were just as smart and talented as the ones today. That’s simply what they could do with the medium at the time. The limitations define the style. And then dogma perpetuates it, as the new generation continues to live with the results of once-great but now outdated thinking.
- mygo 9y ago*The limitations define the style. And then dogma perpetuates it, as the new generation continues to live with the once-great but now outdated results of someone else's thinking.