Dijkstra passed away in 2002, sometimes I wonder what he would write nowadays given that the world took the opposite direction of everything he deemed as correct in software development.
That is one of his least important contributions, though it was important, because at the time when it was written, even if better programming languages existed, most of the programs were written either in COBOL or in FORTRAN and using ad hoc program structures implemented with a lot of GOTO instructions.
Far more important contributions are that in 1960 he taught everybody how to implement recursive functions and procedures and also how to allocate the parameters and local variables of the ALGOL 60 blocks using stacks, stack pointers and stack frames, and then in the following years he taught everybody how to implement mutual exclusion when concurrent processes access shared resources.
In computing science it is hard to say with certainty who invented first some technique, because many of the early uses of some programming techniques have never been published.
Nonetheless, if someone has discovered earlier some programming trick and they kept it to themselves, that does not really count, what matters is only who published first the technique, teaching everybody how to use it.
Dijkstra is certainly the one who popularized during the sixties and early seventies many of the programming techniques that are now among the most fundamental and which are now implemented in any operating system, in any compiler and in any executable program.
Other examples of people with similarly important contributions to programming are John McCarthy and C.A.R. Hoare.
He was a proponent of a style of programming that was reasonable... you could reason about it and prove / demonstrate that it is doing what it should within that block of code as being correct.
Imagine teaching someone BASIC or FORTRAN...
IF (IA .GT. 0 .AND. IB .GT. 0 .AND. IC .GT. 0) GOTO 10
WRITE (6, 602)
602 FORMAT (42H IA, IB, AND IC MUST BE GREATER THAN ZERO.)
STOP 1
10 CONTINUE
Dijkstra's approach to programming help take software development from a craft where each woodworker did things their own way and going from one shop to another meant relearning everything to something were one could more easily reason about how an application worked by removing some of the ability to write unstructured code. You can still write it... and I'm sure you can find some code that is convoluted ("... the determined Real Programmer can write FORTRAN programs in any language." https://www.ee.torontomu.ca/~elf/hack/real-programmers.html ).
Structured programming is also easier to teach. Yes, you can teach people how to write line numbered BASIC but the challenge is also teaching them discipline to not cut off their fingers when doing it. The structured programming approach it becomes easier to enforce that discipline as part of teaching ... and if they go and do dangerous things after they graduate from college, that's up to them.
idk how old you are, but there there was a style in the 70s where goto was the only control flow operator used in a lot of codebases, and it was absolutely horrible.
I'm in my 40s, wasn't coding in the 70s. Horrible use of code is a different thing from removing something entirely, though. Just that almost every language removed goto as a response is kind of amazing to me.
My objective is to extract and discuss interesting fragments from these EWDs. Each of my discussions will appear as a post in one of the following three diaries:
What did Dijkstra do 50 years ago? Check out my diary of the 1960s.
What did Dijkstra do 40 years ago? Check out my diary of the 1970s.
What did Dijkstra do 30 years ago? Check out my diary of the 1980s.***
Dijkstra passed away in 2002, sometimes I wonder what he would write nowadays given that the world took the opposite direction of everything he deemed as correct in software development.
I honestly never got why in college his opinions were just taken as mandates. I never bough into the "goto considered harmful" argument, for example.
That is one of his least important contributions, though it was important, because at the time when it was written, even if better programming languages existed, most of the programs were written either in COBOL or in FORTRAN and using ad hoc program structures implemented with a lot of GOTO instructions.
Far more important contributions are that in 1960 he taught everybody how to implement recursive functions and procedures and also how to allocate the parameters and local variables of the ALGOL 60 blocks using stacks, stack pointers and stack frames, and then in the following years he taught everybody how to implement mutual exclusion when concurrent processes access shared resources.
In computing science it is hard to say with certainty who invented first some technique, because many of the early uses of some programming techniques have never been published.
Nonetheless, if someone has discovered earlier some programming trick and they kept it to themselves, that does not really count, what matters is only who published first the technique, teaching everybody how to use it.
Dijkstra is certainly the one who popularized during the sixties and early seventies many of the programming techniques that are now among the most fundamental and which are now implemented in any operating system, in any compiler and in any executable program.
Other examples of people with similarly important contributions to programming are John McCarthy and C.A.R. Hoare.
He was a proponent of a style of programming that was reasonable... you could reason about it and prove / demonstrate that it is doing what it should within that block of code as being correct.
Imagine teaching someone BASIC or FORTRAN...
Or for something more complicated... https://github.com/ArthurFerreira2/STARTREK/blob/master/star... ... and arguably, that's well structured (its not doing a GOTO into the middle of a subroutine... I think). Tangent to that source code https://meatfighter.com/startrek1971/ for a port to C# (with line numbered goto).Dijkstra's approach to programming help take software development from a craft where each woodworker did things their own way and going from one shop to another meant relearning everything to something were one could more easily reason about how an application worked by removing some of the ability to write unstructured code. You can still write it... and I'm sure you can find some code that is convoluted ("... the determined Real Programmer can write FORTRAN programs in any language." https://www.ee.torontomu.ca/~elf/hack/real-programmers.html ).
Structured programming is also easier to teach. Yes, you can teach people how to write line numbered BASIC but the challenge is also teaching them discipline to not cut off their fingers when doing it. The structured programming approach it becomes easier to enforce that discipline as part of teaching ... and if they go and do dangerous things after they graduate from college, that's up to them.
idk how old you are, but there there was a style in the 70s where goto was the only control flow operator used in a lot of codebases, and it was absolutely horrible.
I'm in my 40s, wasn't coding in the 70s. Horrible use of code is a different thing from removing something entirely, though. Just that almost every language removed goto as a response is kind of amazing to me.
The website is maintained by Edgar Graham Daylight who is a devoted follower of Dijkstra - https://www.dijkstrascry.com/about
There is lots of neat information here for Dijkstra fans.
In particular (from https://www.dijkstrascry.com/);
My objective is to extract and discuss interesting fragments from these EWDs. Each of my discussions will appear as a post in one of the following three diaries:
NOTE: Some interesting articles;1) T.H.E. Multiprogramming System - https://www.dijkstrascry.com/node/77
2) Program Execution as a Living Tree - https://www.dijkstrascry.com/node/109
3) Things Dijkstra would like to do - https://www.dijkstrascry.com/node/110