Re: Recursion, Yo

On 19/04/2024 16:26, Tim Rentsch wrote:

Michael S <already5chosen@yahoo.com> writes:
 

On Mon, 15 Apr 2024 20:36:58 +0200
Janis Papanagnou <janis_papanagnou+ng@hotmail.com> wrote:
>

Algol 68 and C are so different that mutual understanding might be
difficult depending on personal background, focus, and fantasy. :-)

>
Interesting take.
I never learned Algol-68, but from pieces of info that I occasionally
got I was always thinking of it as rather similar to 'C'.
Both languages originated from common ancestor (Algol-60) and changed
it in similar directions, e.g. blurring the line between operators and
expression, making function pointers first class citizen, allowing
declaration of variables at block scope.
I think, in the past, when I remembered more about Algol-68, I had seen
more similarities.

 Algol 60 already had block scope declarations.
 Algol 60 may not have had (pointer to) function/procedure variables,
but it did allow procedure identifiers as arguments to a procedure
call, and procedure variables are an obvious generalization.
 Relative to Algol 60, C slightly expanded what forms are allowed in
expressions, but mainly as a way to simplify the language syntax:
    * no separate cases for assignment / function call statements
    * so for()'s are more general and don't need specializing
 In contrast, in Algol 68 the notion of "expression" is expanded
to allow the possibility of arbitrary variable declarations and
loops (IIANM; certainly I am not an expert on Algol 68).
 Furthermore there are some significant differences between C and
Algol 60:
    * Algol allows nested functions (aka procedures), but C doesn't
    * Algol has call by name, C is strictly call by value
    * Arrays are first class types in Algol, but not in C (and C
     has pointer arithmetic as an essential part of the language,
     which TTBOMK is not the case in any Algol-derived language)
    * Algol is "strict" whereas C is "lax" - for example, in Algol
     the controlling expression of an 'if' statement must be a
     'Boolean expression', whereas in C it's just any expression
 To me, Algol 68 represents an expansion and extension of the
Algol 60 language philosophy, whereas C represents a deliberate
departure from that philosophy;  not necessarily a radical
departure, but a departure nonetheless.  Certainly C has some
similarities to Algol 68, but I wouldn't say C and Algol 68
are similar languages, only that they have a few similarities.

I can't see any connection between Algol68 and C; I'm surprised at people who say they do.
C was put together together as a systems language to do a job, not to implemement some esoteric concept of a language that few could understand.
I understood it was based on languages like B and BCPL.
Actually there is a closer connection between my systems language, created 10 years after C, which was also created for purely practical purposes, and Algol68, largely because I borrowed much of its syntax (including the interchangeability of statements and expressions).
But I would be first to admit that the similarity stops there.