Questions for Manfred

e1_t — 2002-05-14 23:02:55

Out of curiosity, I was just wondering what does dip stand for? And 

what made you choose to name the combinator that dequotes quotations 

i?

I have no objections to their names nor can I think of a better way 

to name them but I just thought it would be interesting to know.



Ivan

Manfred von Thun — 2002-07-09 00:27:21

Dear friends



    As you know from my last posting, I have been on a long

once-in-a-decade holiday. Now I am back at work, and will

respond to the concatenative emails as soon as I can.



    I flew from Melbourne to Rome, picked up a hire car and

started driving - on what for me of ourse was the wrong side

of the road. It was awful the first few days. I stayed on

the autostradas initially to avoid the cities and got to

the South of France all in one piece. That was to visit

relatives for a few days.



    Then into the Alps to see some _real_ mountains which

I had not seen for decades, because here in Australia there

is nothing over 2000 meters. The Mont Blanc at 4800 really

is something to see, especially from a neighbouring peak

of 3800 which one can reach by a cable car.



    Later through Switzerland into Germany, in Franfurt visited

one old friend from school whom I had not seen for 45 years.

On to my hometown Hamburg where I stayed with relatives and

met up with some other old friends from school that I do see

whenever I do come back. It is always as if I had been away

for a week - quite amazing.



    Later slowly down to the South of Germany again, into Austria

through the Alps and into Italy. Stayed in Florence for a couple

of days to see a small portion of the sights. Finally back to

Rome airport - I skipped Rome because there wasn't any time left.



    Impressions? Europe is expensive on an Australian salary, the

traffic speed and density is terrifying, parking is difficult.

The people were always friendly everywhere, and a very high

proportion speak at least a little English - and they were quite

happy to use it when they heard my attempts as Italian or French.



    Europe - oh, yes. But it is so crowded, alas.



    - Manfred

Manfred von Thun — 2002-07-09 00:47:36

On Tue, 14 May 2002, e1_t wrote:



 > Out of curiosity, I was just wondering what does dip stand for? And 

> what made you choose to name the combinator that dequotes quotations 

> i?



 
[..]



The dip combinator dives underneath the top of the stack, does

something there and finally restores that under which it dived (dove?).

I was initially tempted to call it "dive". But it also seemed to dip

a quoted program into the stack to make it do some work there. 

So I chose "dip".



The i combinator is the simplest and purest. It just executes the

quotation, and in a way it applies that quotation to the rest of

the stack to return a new stack. So for a while I was tempted to

call it "apply". But of course Joy does not have application in

the normal sense, so that was out. The combinator interprets the

quoted program on top of the stack, so it might have been called

"interpret" or "i" for short. It also bears a strong resemblance

to the I combinator of combinatory logic, where  I f = f reminiscient

of [..] i ==  .. 

 

It has always been a problem finding suitable names for concepts

in Joy that have no counterparts in the literature.



  - Manfred