6 ms·

What makes APL different from, say, Lisp or Haskell? Do you have tutorials to recommend?

by ced 13y ago

robomartin 13y ago
I'd say abstraction and notation. Start here: http://www.jdl.ac.cn/turing/pdf/p444-iverson.pdf http://www.jdl.ac.cn/turing/pdf/p444-iverson.pdf
aidos 13y ago
Definitely watch this video http://www.youtube.com/watch?v=a9xAKttWgP4 http://www.youtube.com/watch?v=a9xAKttWgP4
- jkarni 13y ago
  APL has its own codepage? I have to say, that's a better and simpler way of avoiding success at all costs than Haskell ever found. Not that I dislike the idea -- on the contrary, I'm inclined to conclude from my excitement over this and Haskell that I dislike success...
  - lifeisstillgood 13y ago
    Haskell has a rule - to avoid popularity at all costs
    - gnuvince 13y ago
      You should parse it as "avoid (popularity at all costs)" rather than "(avoid popularity) at all costs".
    - simonh 13y ago
      Well of course it does. Popularity is a side effect.
  - astrobe_ 13y ago
    Well in the end it doesn't matter if your language is looking for popularity or not. What matters is what you can do with it. You think a language with weird symbols all around can't win? Just look at Pearl. On a related note, if one plans to sell the Language of The Future Of Programming, I swear this thing will know the same fate as Planner, NLS, Sketchpad, Prolog, Smalltalk and whatnot if it cannot help me with the problems I have to solve just tomorrow.
  - keithpeter 13y ago
    Try J. Or Kona (open source K). All ascii characters.
GeneralMayhem 13y ago
It's very hard to find good tutorials on APL because it's not very popular and most of its implementations are closed-source and not compatible with each other's language extensions, but it's most recognizable for its extreme use of non-standard codepoints. Every function in APL is defined by a single character, but those characters range from . to most of the Greek alphabet (taking similar meanings as in abstract math) to things like ⍋ (sort ascending). Wikipedia has a few fun examples if you just want a very brief taste; you can also read a tutorial from MicroAPL at http://www.microapl.com/apl/tutorial_contents.html http://www.microapl.com/apl/tutorial_contents.html It's mostly good for being able to express mathematical formulas with very little translation from the math world - "executable proofs," I think the quote is - and having matrices of arbitrary dimension as first-class values is unusual if not unique. But for any practical purpose it's to Haskell what Haskell is to Java.
- mietek 13y ago
  > But for any practical purpose it's to Haskell what Haskell is to Java. Can you elaborate on this? As I understand, the core strengths of APL are succinct notation, built-in verbs which operate on vectors/matrices, and a requirement to program in a point-free style. All of this can be done in Haskell.
  - jfarmer 13y ago
    A Java programmer unfamiliar with Haskell looks at a Haskell program and shouts, "I can't make even the slightest bit of sense out of this!" A Haskell programmer unfamiliar with APL looks at an APL program and...
    - mietek 13y ago
      Most Haskell programmers should be familiar with right-to-left point-free style, and should be able to infer that symbols stand in for names. Of course, understanding the individual symbols is a different matter, but hardly requiring a conceptual leap.
    - asdasf 13y ago
hutch 13y ago
All the decent tutorials that I know of were in book form. Unless someone's scanned them they're gone. I know mine got destroyed in a flooded basement. Now, I didn't learn APL from a tutorial, I learned it (in 1976) from a book. This book: http://www.jsoftware.com/papers/APL.htm http://www.jsoftware.com/papers/APL.htm from 1962. If my memory hasn't been completely corrupted by background radiation, I've seen papers as early as the mid 1950s about this notation. APL started out as a notation for expressing computation (this is not precise but good enough). As far as I'm concerned it's sitting at a level of abstraction higher than Haskell (arguably like a library overtop Haskell). Now, in the theme of this thread, APL was able to achieve all of this given the constraints at the time. The MCM/70 was a microprocessor based laptop computer that shipped in 1974 (demonstrated in 1972, some prototypes delivered to customers in 1973) and ran APL using an 80 kHz (that kilo) 8008 (with a whole 8 bytes of stack) with 2 kBytes (that's kilo) RAM or maxed out at 8 kB (again, that's kilo) of RAM. This is a small slow machine that still ran APL (and nothing else). IEEE Annals of Computer History has this computer as the earliest commercial, non-kit personal computer (IEEE Annals of the History of Computing, 2003: pg. 62-75). And, I say again, it ran APL exclusively. Control Data dominated the super computer market in the 70s. The CDC 7600 (designed by Cray himself, 36.4 MHz with 65 kWord (a word was some multiple of 12 bits, probably 60 bits but I'm fuzzy on that) and about 36 MFLOPS according to wikipedia) was normally programmed in FORTRAN. In fact, this would be a classic machine to run FORTRAN. However, the APL implementation available was often able to outperform it, almost always when coded by an engineer (and I mean like civil, mechanical, industrial, etc engineer, not a software engineer) rather than someone specialising in writing fast software. I wish everyone would think about what these people accomplished given those constraints. And think about this world and think again about Bret Victor's talk.
- mietek 13y ago
  Thank you. Please consider writing a blog so that this knowledge doesn't disappear. Were those destroyed tutorials published books?
  - hutch 13y ago
    The ones I remember were all books. At the time, I thought this was one of the best books available: http://www.amazon.com/APL-Interactive-Approach-Leonard-Gilman/dp/0471093041 http://www.amazon.com/APL-Interactive-Approach-Leonard-Gilma... -- but I don't know if I'd pay $522 for it... actually I do know, and I wouldn't. The paper covered versions are just fine, and a much better price :-) EDIT: I just opened the drop down on the paper covered versions. Prices between $34.13 and $1806.23!!! Is that real?!? Wow, I had five or six copies of something that seems to be incredibly valuable. Too late for an insurance claim on that basement flood.

What makes APL different from, say, Lisp or Haskell? Do you have tutorials to recommend?

by ced 13y ago

What makes APL different from, say, Lisp or Haskell? Do you have tutorials to recommend?

I'd say abstraction and notation. Start here: http://www.jdl.ac.cn/turing/pdf/p444-iverson.pdf http://www.jdl.ac.cn/turing/pdf/p444-iverson.pdf

aidos 13y ago

Definitely watch this video http://www.youtube.com/watch?v=a9xAKttWgP4 http://www.youtube.com/watch?v=a9xAKttWgP4

jkarni 13y ago
APL has its own codepage? I have to say, that's a better and simpler way of avoiding success at all costs than Haskell ever found. Not that I dislike the idea -- on the contrary, I'm inclined to conclude from my excitement over this and Haskell that I dislike success...
- lifeisstillgood 13y ago
  Haskell has a rule - to avoid popularity at all costs
  - gnuvince 13y ago
    You should parse it as "avoid (popularity at all costs)" rather than "(avoid popularity) at all costs".
  - simonh 13y ago
    Well of course it does. Popularity is a side effect.
- astrobe_ 13y ago
  Well in the end it doesn't matter if your language is looking for popularity or not. What matters is what you can do with it. You think a language with weird symbols all around can't win? Just look at Pearl. On a related note, if one plans to sell the Language of The Future Of Programming, I swear this thing will know the same fate as Planner, NLS, Sketchpad, Prolog, Smalltalk and whatnot if it cannot help me with the problems I have to solve just tomorrow.
- keithpeter 13y ago
  Try J. Or Kona (open source K). All ascii characters.

GeneralMayhem 13y ago

It's very hard to find good tutorials on APL because it's not very popular and most of its implementations are closed-source and not compatible with each other's language extensions, but it's most recognizable for its extreme use of non-standard codepoints. Every function in APL is defined by a single character, but those characters range from . to most of the Greek alphabet (taking similar meanings as in abstract math) to things like ⍋ (sort ascending). Wikipedia has a few fun examples if you just want a very brief taste; you can also read a tutorial from MicroAPL at http://www.microapl.com/apl/tutorial_contents.html http://www.microapl.com/apl/tutorial_contents.html It's mostly good for being able to express mathematical formulas with very little translation from the math world - "executable proofs," I think the quote is - and having matrices of arbitrary dimension as first-class values is unusual if not unique. But for any practical purpose it's to Haskell what Haskell is to Java.

mietek 13y ago
> But for any practical purpose it's to Haskell what Haskell is to Java. Can you elaborate on this? As I understand, the core strengths of APL are succinct notation, built-in verbs which operate on vectors/matrices, and a requirement to program in a point-free style. All of this can be done in Haskell.
- jfarmer 13y ago
  A Java programmer unfamiliar with Haskell looks at a Haskell program and shouts, "I can't make even the slightest bit of sense out of this!" A Haskell programmer unfamiliar with APL looks at an APL program and...
  - mietek 13y ago
    Most Haskell programmers should be familiar with right-to-left point-free style, and should be able to infer that symbols stand in for names. Of course, understanding the individual symbols is a different matter, but hardly requiring a conceptual leap.
  - asdasf 13y ago

hutch 13y ago

All the decent tutorials that I know of were in book form. Unless someone's scanned them they're gone. I know mine got destroyed in a flooded basement. Now, I didn't learn APL from a tutorial, I learned it (in 1976) from a book. This book: http://www.jsoftware.com/papers/APL.htm http://www.jsoftware.com/papers/APL.htm from 1962. If my memory hasn't been completely corrupted by background radiation, I've seen papers as early as the mid 1950s about this notation. APL started out as a notation for expressing computation (this is not precise but good enough). As far as I'm concerned it's sitting at a level of abstraction higher than Haskell (arguably like a library overtop Haskell). Now, in the theme of this thread, APL was able to achieve all of this given the constraints at the time. The MCM/70 was a microprocessor based laptop computer that shipped in 1974 (demonstrated in 1972, some prototypes delivered to customers in 1973) and ran APL using an 80 kHz (that kilo) 8008 (with a whole 8 bytes of stack) with 2 kBytes (that's kilo) RAM or maxed out at 8 kB (again, that's kilo) of RAM. This is a small slow machine that still ran APL (and nothing else). IEEE Annals of Computer History has this computer as the earliest commercial, non-kit personal computer (IEEE Annals of the History of Computing, 2003: pg. 62-75). And, I say again, it ran APL exclusively. Control Data dominated the super computer market in the 70s. The CDC 7600 (designed by Cray himself, 36.4 MHz with 65 kWord (a word was some multiple of 12 bits, probably 60 bits but I'm fuzzy on that) and about 36 MFLOPS according to wikipedia) was normally programmed in FORTRAN. In fact, this would be a classic machine to run FORTRAN. However, the APL implementation available was often able to outperform it, almost always when coded by an engineer (and I mean like civil, mechanical, industrial, etc engineer, not a software engineer) rather than someone specialising in writing fast software. I wish everyone would think about what these people accomplished given those constraints. And think about this world and think again about Bret Victor's talk.

mietek 13y ago
Thank you. Please consider writing a blog so that this knowledge doesn't disappear. Were those destroyed tutorials published books?
- hutch 13y ago
  The ones I remember were all books. At the time, I thought this was one of the best books available: http://www.amazon.com/APL-Interactive-Approach-Leonard-Gilman/dp/0471093041 http://www.amazon.com/APL-Interactive-Approach-Leonard-Gilma... -- but I don't know if I'd pay $522 for it... actually I do know, and I wouldn't. The paper covered versions are just fine, and a much better price :-) EDIT: I just opened the drop down on the paper covered versions. Prices between $34.13 and $1806.23!!! Is that real?!? Wow, I had five or six copies of something that seems to be incredibly valuable. Too late for an insurance claim on that basement flood.