30 Oct
2011
30 Oct
'11
10:17 a.m.
Liam Proven wrote:
I've done a little Googling and from the few scant mentions I can
find, I can't, TBH, see much different myself, as an outsider looking
in. I understand the namespace distinction (I think) but the syntax
looks nigh-identical from the few snippets I found.
Many functional programming texts depart from pure S-expressions. I
wonder if McCarthy's teaching notation was like that used by Peter
Henderson in "Functional Programming - Application and
Implementation"[1]. This is another good text on list/recursive topics,
but because it introduces new (simple) notation, may be needlessly
confusing if you just want to learn Scheme.
I think the Graham paper is a good starting point, as it's probably less
academic than McCarthy's. Also, the first pages of "Lisp in Small
Pieces"[2] cover the same material in slightly more detail.
The more I read about Lisp, the more I want to
understand... but I
suspect I am too old& even in my youth I never got much past BASIC.
The only Lisp I've been able to follow code in is Dylan, and Dylan
seems to be rather moribund... :?(
JMC actually used what he called Lisp 2 in his classes, an algebraic
notation not unlike Dylan, very Algol-like in flavor. Not surprising,
when you think of the relative ages of Lisp and Algol. ...
Wouldn't be my weapon of choice, but if you really love BBC BASIC, then
go for it. Maybe you could actually compile to BASIC source (& even
exploit the inline 6502 assembler) :)
The two books I cited deal with implementation, which might help. There
is also this nice implementation walkthrough (in Perl, but that's
probably a fair bit less painful than BASIC :):
http://billhails.net/Book/front.html
The way I *really* learned Lisp was by looking at
toy implementations,
especially one written in Pascal. That was back in the early or mid 1980s,
way before the Web, so I don't remember where it was published. I read the
paper in the Math library @ Stanford (which no longer has a lot of the old
working papers collection on paper, just on fiche where it's a lot harder
to browse). If you like, I can send you the source to my variant, or make
it publicly readable on the Toad-1 at the museum.
Hmmm. Interesting. I wonder if I can remember enough BBC BASIC to
implement a very crude Lisp in it. :?D If you get access JMC's 1960 paper in ACM,
read it. The APPLY function
which Paul Graham skips in his precis is a wonder in itself, and is the
reason that LISP 1.5 and InterLISP are "evalquote" while PDP-1 LISP,
MACLISP, CL& Scheme are "eval": The evaluation loop in the former goes
(print (apply (read) (read)))
vs. (print (eval (read)))
Enough for this evening.
Many thanks! Lots of food for further reading there.
May I ask: what do folk think of the quote I've often seen cited:
...
I find programming language and operating system car/{whatever}
analogies add little to the conversation :)
--Toby
[1]
http://www.abebooks.com/servlet/SearchResults?an=henderson&sts=t&tn…
[2]
http://www.abebooks.com/servlet/SearchResults?sts=t&tn=Lisp+in+Small+Pi…