Please explain some of Paul Graham's points on LISP

Posted by kunjaan on Stack Overflow See other posts from Stack Overflow or by kunjaan
Published on 2010-04-25T22:30:32Z Indexed on 2010/04/25 22:33 UTC
Read the original article Hit count: 927

Filed under:

lisp

|

Scheme

|

functional-programming

|

paul-graham

I need some help understanding some of the points from Paul Graham's article http://www.paulgraham.com/diff.html

A new concept of variables. In Lisp, all variables are effectively pointers. Values are what have types, not variables, and assigning or binding variables means copying pointers, not what they point to.
A symbol type. Symbols differ from strings in that you can test equality by comparing a pointer.
A notation for code using trees of symbols.
The whole language always available. There is no real distinction between read-time, compile-time, and runtime. You can compile or run code while reading, read or run code while compiling, and read or compile code at runtime.
- What do these points mean
- How are they different in languages like C or Java?
- Do any other languages other than LISP family languages have any of these constructs now?

© Stack Overflow or respective owner

Related posts about lisp

Why do you like Lisp ?

as seen on Programmers - Search for 'Programmers'
Why does Paul Graham advocate Lisp? Why did ITA Software choose Lisp over other High Level languages? Lisp obviously is an advantage for the AI stuff but I don't think Lisp is any faster than Java, C# or as a matter of fact faster than C. Still it is considered as a Hackers language? I am not a master… >>> More
Why is Lisp useful?

as seen on Programmers - Search for 'Programmers'
Lisp obviously is an advantage for the AI stuff but it doesn't appear to me that Lisp is any faster than Java, C#, or even C. I am not a master of Lisp, but I find it incredibly difficult to understand the advantage one would get in writing Business Software in Lisp. Yet it is considered as a hacker's… >>> More
Emacs 23.1 make error 139 in Mac OS X 10.6.3

as seen on Stack Overflow - Search for 'Stack Overflow'
When I try to compile GNU Emacs 23.1 on my machine with Mac OS X 10.6.3 I repeatedly get the following ending: Directories: /src/emacs-23.1/lisp/. /src/emacs-23.1/lisp/./calc /src/emacs-23.1/lisp/./calendar /src/emacs-23.1/lisp/./emacs-lisp /src/emacs-23.1/lisp/./emulation /src/emacs-23.1/lisp/./erc… >>> More
Why not port Linux kernel to Common Lisp?

as seen on Stack Overflow - Search for 'Stack Overflow'
Conventional wisdom states that OS kernels must be written in C in order to achieve the necessary levels of performance. This has been the justification for not using more expressive high level languages. However, for a few years now implementations of Common Lisp such as SBCL have proven to be… >>> More
Lisp Style question label local functions or not?

as seen on Stack Overflow - Search for 'Stack Overflow'
I was wondering if there is a standard practice regarding the use of labels in Lisp. I've been messing around with a Lisp implementation of the algorithm described in the first answer here http://stackoverflow.com/questions/352203/generating-permutations-lazily My current version uses labels to… >>> More

Related posts about Scheme

About "If.." in Scheme (plt-scheme)

as seen on Stack Overflow - Search for 'Stack Overflow'
I had a pretty simple requirement in my Scheme program to execute more than one statement, in the true condition of a 'if'. . So I write my code, something like this: (if (= 1 1) ((expression1) (expression2)) ; these 2 expressions are to be executed when the condition is true (expression3)… >>> More
Detecting EOF in a Binary File using Scheme

as seen on Stack Overflow - Search for 'Stack Overflow'
(define (read-all-input) (local ((define line (bytes->list (read-bytes 4)))) (if (eof-object? line) empty (cons line (read-all-input))))) (void (read-all-input)) The above code fails because bytes-list expects an argument of type byte string, but is given # >>> More
Scheme: Detecting duplicate elements in a list

as seen on Stack Overflow - Search for 'Stack Overflow'
Does R6RS or Chez Scheme v7.9.4 have a library function to check if a list contains duplicate elements? Alternatively, do either have any built in functionality for sets (which dis-allow duplicate elements)? So far, I've only been able to find an example here. The problem with that is that it doesn't… >>> More
Traversing Scheme function as a list

as seen on Stack Overflow - Search for 'Stack Overflow'
Isn't it possible to treat functions in Scheme as any other list? Basically, what I want do to is something like this: (define (foo) "hello") (cdr foo) ; or similar, should return the list ((foo) "hello") I've found a similar discussion about this, and I feel a bit disappointed if this is not… >>> More
Scheme implementations - what does it mean?

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I'm a beginning student in CS, and my classes are mostly in Java. I'm currently going through "Little Schemer" as a self study, and in the process of finding out how to do that I have found numerous references to "implementations" of Scheme. My question is, what are implementations? Are they… >>> More