Edsger Dijkstra – The Man Who Carried Computer Science on His Shoulders

Post by mycall » Mon, Nov 02, 2020, 4:37 AM UTC

User23 wrote: post #158

todd8 wrote: post #82

I read Dijkstra's goto considered harmful in college, circa 1970. I was a young programmer at the time, and it made me think and reconsider how and why big programs were often hard to understand. Years later, in grad school, my research was on program verification. Dijkstra was a big influence on the field. I attended a lecture at UT Austin that he gave before moving to the US. Dijkstra's approach to proving the corr…

Program verification is a fool's errand and Dijkstra would have been the first to tell you this. The correct approach is program construction following derivation rules that do not admit error. You don't need to verify a program produced from a specification this way anymore than you need to prove a proof by construction. It baffles me that to this day the distinction defies comprehension for so many in our field.

Post by cambalache » Mon, Nov 02, 2020, 5:45 PM UTC

silicon2401 wrote: post #202

cambalache wrote: post #140

Earlier quoted context omitted.

Thing is any local media wont display it "in your face" like an America show would do it, it is just part of the environment. Paraphrasing Borges, "How do you identify an actual desert people literary work? it's the one which does not mention camels" This reminds me one thing I find irritating about SF in general and SF movies in particular. They hardly portrait technology use in an organic way. Do you want to see a…

That sounds like just what I'd be interested in watching. Any suggestions? That's a good example. I often do the reverse: watching 90s or older movies with modern eyes. It can be incredibly refreshing to watch older movies that have a slower and more relatable vibe.

Post by ncmncm » Tue, Nov 03, 2020, 4:19 AM UTC

User23 wrote: post #159

todd8 wrote: post #60

Earlier quoted context omitted.

Early LISP implementations used dynamic scope. This means that non-local references in a function search for the variable's binding in the call chain: if A calls B then when B uses nonlocal variable x it refers to the x in A, not necessarily the x that belongs in the lexical parent of B as seen in the source code. (Unlike C, Algol/Pascal/LISP can all define functions inside of other functions. These nested function d…

Algol 60 is a marvel and I feel like it's a language every programmer should learn at least to the point of coding a few basic algorithms. The closest analog of call by-name I can think of is Common Lisp macros.