Re: The Red Language

[chl@clw.cs.man.ac.uk (Charles Lindsey)]

In <EGrv5y.C2D@world.std.com> bobduff@world.std.com (Robert A Duff) writes:

>Well, I suppose in the bad old days, a "pass" in a compiler had
>something to do with reading a representation of the source program from
>the disk, and writing back a different representation.  I agree this is
>not a useful way to look at it.  (I recall using a Pascal compiler that
>required me to remove the "pass 1" floppy, and insert the "pass 2"
>floppy, for each compile.)

In the REAL "bad old days" (before programmers took to eating quiche), the
passes were done to/from tape.

>>Note that in Algol-68, which uses operand type overloading only, there is
>>indeed a one pass algorithm in the sense I define it above.

>Could you briefly explain the Algol 68 rule?  Better yet, tell me where
>I can get my hands on the manual!  I've read stuff *about* Algol 68, but
>I want to read the actual language definition (which, I understand, is
>rather tough going).

You can deduce the operator solely from the type of its two operands.
There are some "related" rules which prevent you from declaring two
versions of an operator which could have confused that deduction (remember
that some coercions are allowed on the operators).

References:

Revised Report on the Algorithmic Language ALGOL 68.
	Acta Informatica Vol 5 (1975) pts 1-3
or	SIGPLAN Notices Vol 12 No 5 (1977)

Or send me your snail mail address and I will send you a microfiche (a bit
blurry :-( ).

See also my paper in the History of Pragramming Languages-II (ACM Press).

-- 
Charles H. Lindsey ---------At Home, doing my own thing-------------------------
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