Infocom on PDP-11

[Andy Holt]

> Then again, Algol 68 is the source of many C++ features -- iostreams
> for example.
>
> Let's see, Algol 60 brought us:
> - Formal grammars (BNF)
> - Block structure
> - Local variables
  um, Fortran's variables were local - but
     only local or global (Common) - nothing in between
> - Scope of names
> - Declarations
  make that Mandatory declarations ... and even there the predecessors of
COBOL were earlier
> - Type safety
>
> and indirectly
> - structured programming
  everybody has their own definition of structured programming ...
> - parser generators
>
>  Tom> The Whetsone Algol compiler ran, in one pass, as fast as the
>  Tom> source-input reader hardware, in 7000 words of memory! Though
>  Tom> slow, it's a full-featured language, unlike C which is basically
>  Tom> a portable assembler (I loved writing in C).
Tho' those 7000 words were 48-bit (on the KDF9). The ICT/ICL1900 series
had an Algol (subset) that ran on a 4K (24-bit word) computer and a full
compiler for an 8K machine ... I can't remember, but I think the #XALE
(disk compiler) and #XALM (corresponding tape-based compiler) were for
16K. I think, also, that IBM's Algol compiler was an "E" code so
intended for a 32KB '360 ... not that the PL/I E compiler would run on that
size machine :-(

>
> I don't know how big the first Algol 60 compiler (at MC Amsterdam) was
> -- probably similar, quite possibly smaller.
>
>  Tom> Algol had it's share of horrors, but man it is the basis for
>  Tom> nearly all modern languages. C's block and scope structure came
>  Tom> directly from Algol.
>
> Lobotomized, of course -- C left out a bunch of important parts from
> the Algol block structure.
Some because C is really from the Fortran tradition (Dirty tricks are
sometimes useful and too strong typing and structure prevent such); some
because they had been discovered to be more problematic than helpful.
Algol 60 -> CPL -> BCPL -> B -> C (importing much from PL/I* ... which
  was a union of concepts from Algol 60, Fortran IV, and COBOL using
  Algol structure)
* this linkage is not normally recognised in histories of programming
languages, but when it is considered that the originators of C had been
involved in the Multics project ... an OS written in PL/I; the only
previous production OS that had been written in a HLL was that of the
Burroughs machines ... using a version of Algol (to complete the
circularity of these references).

> Hm.  Algol 60 certainly has no OO nature.  Algol 68 does, the
> beginnings of it.

Simula 67 was a derivative of Algol 60 that is normally recognised as the
foundation of OO.

Andy
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