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...And I think we need to get rid of the idea that those differences necessarily precludes them from being Lisps. Because make no mistake, they are all Lisps.

...And I think we need to get rid of the idea that those differences necessarily precludes them from being Lisps. Because make no mistake, they are all Lisps. You said that they didn't share code, libraries, books, or community. First off, they do share community to some degree: there's a good bit of overlap between all of them. It's not all overlap, but there's plenty there. Second off, you know what other languages don't share code, library, or books with the Common Lisp we know today? MACLisp. Interlisp. Portable Standard Lisp. Lisp 1.5. Emacs Lisp. AutoLisp. ISLISP. Eulisp. Arc. To say nothing of Hy, LFE, MDL, Newlisp, NIL, Picolisp, and yes, Clojure and Scheme. And there are countless others. Lisp has always been a language of many different dialects. Why should we pretend it's any different now?

gkya 10y ago
Second tthis. The term Lisp in CS is like Romance in linguistics, it indicates a family of languages that belong to different similar but not identical cultures which contribute to them and yet still the languages come from a common ancestor and are more similar than not while at times not easily mutually comprehensible.
- lispm 10y ago
  People who can speak German dialects can understand each other. Books written in some form of German can be understood by most readers. Same for English dialects. For Germanic languages this is not the case. English and German are both Germanic, but knowing German does not let me read English literature. Lisp is like English: a basic vocabulary, a basic syntax, basic semantics understood by all readers. I can look at some basic Lisp code and I will understand the program. A Lisp developer looking at Clojure code will understand very very little.
  - qwertyuiop924 10y ago
    Really? It's pretty easy to get, with a few pointers here and there.
    - lispm 10y ago
      Good luck reading Thomas Mann or Hermann Hesse in German... Any modern fiction. No chance.
      - qwertyuiop924 10y ago
        rolls eyes Not German, Clojure. Clojure is pretty easy.
        lispm 10y ago
        Really? You must be really good at Clojure. Then you can explain this: user=> (list 1 2 3) (1 2 3) user=> (list? (list 1 2 3)) true so (1 2 3) is a list. user=> (cons 0 (list 1 2 3)) (0 1 2 3) user=> (list? (cons 0 (list 1 2 3))) false (0 1 2 3) is not a list? user=> (list? '(0 1 2 3)) true But then it is??? WTF? Compare ELISP: ELISP> (listp (list 1 2 3)) t ELISP> (listp (cons 0 (list 1 2 3))) t and CL: CL-USER> (listp (list 1 2 3)) T CL-USER> (listp (cons 0 (list 1 2 3))) T
        qwertyuiop924 10y ago
        That's pretty screwed up, but having brain-damged function naming doesn't mean it's not lisp. And a few odd corners does not illegability make.
        kazinator 10y ago
        Try TXR Lisp; you will be charmed. http://www.nongnu.org/txr http://www.nongnu.org/txr
        qwertyuiop924 10y ago
        Thanks kaz, but I've already got the manpage bookmarked. I haven't looked at it in-depth yet, but it seems to be awk, but better, which is pretty awesome.
  - gkya 10y ago
    English is such an oddball in the Germanic family that I'd count it an outlier. About 40% of its vocabulary is of Latin origin, and in sum about 60% of its vocabulary is made up of loan words. A couple years ago I submitted the "Uncleftish Behaviour" here [1], which demonstrates English with only germanic words. [1] https://news.ycombinator.com/item?id=7671549 https://news.ycombinator.com/item?id=7671549 For the rest of the family, there's a lot of mutual intelligibility. And, a metaphor is a metaphor, no metaphor holds if you dig deep enough. > A Lisp developer looking at Clojure code will understand very very little. This is an assumption, not a fact. Java interop code and (recur) are a bit confusing in the first sight, but not undecipherable. The prog lang that's most like English is C++: too many things are overtly overloaded, see phrasal verbs.
    - lispm 10y ago
      Clojure borrows from C++, C#, Common Lisp, Erlang, Haskell, Mathematica, ML, Prolog, Scheme, Java, Racket, Ruby - according to Wikipedia. I would guess that 10% of its operator names come from Lisp. Okay, that's a wild guess. Let's look at the special forms: def-, if+, do-, let+, quote+, var-, fn-, loop-, recur-, throw-, try-, monitor-enter-, monitor-exit, ... Around three from thirteen special forms have roughly the same name/meaning in Lisp. Let's look at printing: pr-, prn-, print-, println-, newline-. None Lisp names, either they don't exist in Lisp under that name or they do something else. PR and PRN don't exist in Lisp. PRINT prints a newline before printing the object. PRINTLN does not exist in Lisp. NEWLINE is called TERPRI. Thus even for a simple thing as basic IO the API is different.
      - qwertyuiop924 10y ago
        Small differences in IO are usually simple to deal with, and quite common between other lisps, such as Scheme, and picolisp.
lispm 10y ago
Maclisp came from Lisp 1.5. Code was simply ported to Maclisp. Some Lisp 1.5 code runs mostly unchanged in CL. Maclisp shared code with Common Lisp. For a lot of stuff there was a single code base at MIT for several Lisp dialects, including Maclisp. After some time Maclisp development ended and sharing ended. For example the source code for the complex LOOP macro was at one time a single file for Maclisp, NIL, Lisp Machine Lisp and Common Lisp. People ported programs from Maclisp to CL by changing them or by translating them with tools, not by rewriting them. There were also code bases which worked both in early Scheme and CL. Emacs Lisp has a huge CL subset and even includes a version of CLOS. Since both Emacs Lisp and Common Lisp are coming from Maclisp, both languages are very similar anyway. Basic operators are the same, differing in various details - like dialects often do. Common Lisp had Interlisp compatibility packages, while Interlisp was still used. There were translators, too. Xerox had Interlisp and Common Lisp integrated in one Lisp. Kent Pitman wrote an ISLISP compatibility package for Common Lisp. There are compatibility packages for Portable Standard Lisp, which allow the unchanged use of PSL code in Common Lisp. etc etc There is zero code sharing between Lisp, Clojure and Racket. Compatibility with the Lisp 1, Lisp 1.5, Maclisp, Common Lisp, Emacs Lisp, CL, ISLISP, main line of Lisp wasn't a goal for Clojure and Racket. That's fine. They got rid of historical baggage and could design new languages. Basic rule: if a language has LISP in its name, there is some chance that it actually is a LISP. People usually name their language LISP something, to give the impression that the language is compatible with Lisp. They use different names, when the language is different: Scheme, Javascript, Logo, Dylan, Clojure, ... Take a Lisp 1.5 manual, look at the function index and check which functions and special forms are provided. If most of those are absent (or doing something different), it's not a Lisp: append, atom, car, cdr, cond, cons, eq, eval, intern, list, load, map, member, pair, print, read, prog, quote, reverse, return, set, setq, trace, ...
- qwertyuiop924 10y ago
  Most of those things appear in scheme. Slightly different naming, but the same, more or less. To say that there's compatability between Scheme and CL, and no compatability with Racket is ridiculus: Racket has Scheme compatability modes. As for the language being called Lisp if it's Lisp, two of the examples you list in the "non lisp" category do so: Clojure's website claims it is a "dialect of lisp," and AIM-349 describes scheme as "essentially a full-funarg LISP." As make no mistake, all of these languages, from Common Lisp to Clojure to Scheme, are dialects. They have the same origins, and they share many of the same ideas.

gkya 10y ago

Second tthis. The term Lisp in CS is like Romance in linguistics, it indicates a family of languages that belong to different similar but not identical cultures which contribute to them and yet still the languages come from a common ancestor and are more similar than not while at times not easily mutually comprehensible.

lispm 10y ago
People who can speak German dialects can understand each other. Books written in some form of German can be understood by most readers. Same for English dialects. For Germanic languages this is not the case. English and German are both Germanic, but knowing German does not let me read English literature. Lisp is like English: a basic vocabulary, a basic syntax, basic semantics understood by all readers. I can look at some basic Lisp code and I will understand the program. A Lisp developer looking at Clojure code will understand very very little.
- qwertyuiop924 10y ago
  Really? It's pretty easy to get, with a few pointers here and there.
  - lispm 10y ago
    Good luck reading Thomas Mann or Hermann Hesse in German... Any modern fiction. No chance.
    - qwertyuiop924 10y ago
      rolls eyes Not German, Clojure. Clojure is pretty easy.
      - lispm 10y ago
        Really? You must be really good at Clojure. Then you can explain this: user=> (list 1 2 3) (1 2 3) user=> (list? (list 1 2 3)) true so (1 2 3) is a list. user=> (cons 0 (list 1 2 3)) (0 1 2 3) user=> (list? (cons 0 (list 1 2 3))) false (0 1 2 3) is not a list? user=> (list? '(0 1 2 3)) true But then it is??? WTF? Compare ELISP: ELISP> (listp (list 1 2 3)) t ELISP> (listp (cons 0 (list 1 2 3))) t and CL: CL-USER> (listp (list 1 2 3)) T CL-USER> (listp (cons 0 (list 1 2 3))) T
        qwertyuiop924 10y ago
        That's pretty screwed up, but having brain-damged function naming doesn't mean it's not lisp. And a few odd corners does not illegability make.
        kazinator 10y ago
        Try TXR Lisp; you will be charmed. http://www.nongnu.org/txr http://www.nongnu.org/txr
        qwertyuiop924 10y ago
        Thanks kaz, but I've already got the manpage bookmarked. I haven't looked at it in-depth yet, but it seems to be awk, but better, which is pretty awesome.
- gkya 10y ago
  English is such an oddball in the Germanic family that I'd count it an outlier. About 40% of its vocabulary is of Latin origin, and in sum about 60% of its vocabulary is made up of loan words. A couple years ago I submitted the "Uncleftish Behaviour" here [1], which demonstrates English with only germanic words. [1] https://news.ycombinator.com/item?id=7671549 https://news.ycombinator.com/item?id=7671549 For the rest of the family, there's a lot of mutual intelligibility. And, a metaphor is a metaphor, no metaphor holds if you dig deep enough. > A Lisp developer looking at Clojure code will understand very very little. This is an assumption, not a fact. Java interop code and (recur) are a bit confusing in the first sight, but not undecipherable. The prog lang that's most like English is C++: too many things are overtly overloaded, see phrasal verbs.
  - lispm 10y ago
    Clojure borrows from C++, C#, Common Lisp, Erlang, Haskell, Mathematica, ML, Prolog, Scheme, Java, Racket, Ruby - according to Wikipedia. I would guess that 10% of its operator names come from Lisp. Okay, that's a wild guess. Let's look at the special forms: def-, if+, do-, let+, quote+, var-, fn-, loop-, recur-, throw-, try-, monitor-enter-, monitor-exit, ... Around three from thirteen special forms have roughly the same name/meaning in Lisp. Let's look at printing: pr-, prn-, print-, println-, newline-. None Lisp names, either they don't exist in Lisp under that name or they do something else. PR and PRN don't exist in Lisp. PRINT prints a newline before printing the object. PRINTLN does not exist in Lisp. NEWLINE is called TERPRI. Thus even for a simple thing as basic IO the API is different.
    - qwertyuiop924 10y ago
      Small differences in IO are usually simple to deal with, and quite common between other lisps, such as Scheme, and picolisp.

lispm 10y ago

Maclisp came from Lisp 1.5. Code was simply ported to Maclisp. Some Lisp 1.5 code runs mostly unchanged in CL. Maclisp shared code with Common Lisp. For a lot of stuff there was a single code base at MIT for several Lisp dialects, including Maclisp. After some time Maclisp development ended and sharing ended. For example the source code for the complex LOOP macro was at one time a single file for Maclisp, NIL, Lisp Machine Lisp and Common Lisp. People ported programs from Maclisp to CL by changing them or by translating them with tools, not by rewriting them. There were also code bases which worked both in early Scheme and CL. Emacs Lisp has a huge CL subset and even includes a version of CLOS. Since both Emacs Lisp and Common Lisp are coming from Maclisp, both languages are very similar anyway. Basic operators are the same, differing in various details - like dialects often do. Common Lisp had Interlisp compatibility packages, while Interlisp was still used. There were translators, too. Xerox had Interlisp and Common Lisp integrated in one Lisp. Kent Pitman wrote an ISLISP compatibility package for Common Lisp. There are compatibility packages for Portable Standard Lisp, which allow the unchanged use of PSL code in Common Lisp. etc etc There is zero code sharing between Lisp, Clojure and Racket. Compatibility with the Lisp 1, Lisp 1.5, Maclisp, Common Lisp, Emacs Lisp, CL, ISLISP, main line of Lisp wasn't a goal for Clojure and Racket. That's fine. They got rid of historical baggage and could design new languages. Basic rule: if a language has LISP in its name, there is some chance that it actually is a LISP. People usually name their language LISP something, to give the impression that the language is compatible with Lisp. They use different names, when the language is different: Scheme, Javascript, Logo, Dylan, Clojure, ... Take a Lisp 1.5 manual, look at the function index and check which functions and special forms are provided. If most of those are absent (or doing something different), it's not a Lisp: append, atom, car, cdr, cond, cons, eq, eval, intern, list, load, map, member, pair, print, read, prog, quote, reverse, return, set, setq, trace, ...

qwertyuiop924 10y ago
Most of those things appear in scheme. Slightly different naming, but the same, more or less. To say that there's compatability between Scheme and CL, and no compatability with Racket is ridiculus: Racket has Scheme compatability modes. As for the language being called Lisp if it's Lisp, two of the examples you list in the "non lisp" category do so: Clojure's website claims it is a "dialect of lisp," and AIM-349 describes scheme as "essentially a full-funarg LISP." As make no mistake, all of these languages, from Common Lisp to Clojure to Scheme, are dialects. They have the same origins, and they share many of the same ideas.