6 ms·

An early Clojure implementation in Common Lisp

56 points by fogus 16y ago

jjames 16y ago
I read the "early" as pre-release and thought someone was trying to re-implement clojure in CL. I'm relieved. What's the backstory on this, fogus? I've not read about a CL Clojure pre-dating the JVM implementation. Was this just a prototype or was there a plan to platform on CL at some point?
- fogus 16y ago
  I believe (caveat emptor) that this was an early prototype.
francoisdevlin 16y ago
Does anyone else feel like they're looking at baby pictures?
- zachbeane 16y ago
  http://www.informatimago.com/develop/lisp/small-cl-pgms/aim-8/aim-8.html http://www.informatimago.com/develop/lisp/small-cl-pgms/aim-...
  - alexk7 16y ago
    Now that's "early"! (The link above points to McCarthy texts from 1959 about Lisp)
  - fogus 16y ago
    I wonder what happened to Part 2?
    - fogus 16y ago
      I'll answer my own question. McCarthy states in History of Lisp, "Part II was never written but was intended to contain applications to computing with algebraic expressions." Here's hoping he gets around to writing it one day. :-)
KC8ZKF 16y ago
He had DotLisp, a Lisp on the CLR, before Clojure as well. http://dotlisp.sourceforge.net/dotlisp.htm http://dotlisp.sourceforge.net/dotlisp.htm http://groups.google.com/group/comp.lang.lisp/msg/e31b38c8cc0e6a23 http://groups.google.com/group/comp.lang.lisp/msg/e31b38c8cc...
jimbokun 16y ago
I was looking for reader macros for recognizing {} as hash tables and [] as vectors. To me, that is one of the biggest innovations in Clojure over Lisps that came before, the expansion of the concept of S-expressions.
- francoisdevlin 16y ago
  Personally, my money is on the seq abstraction. YMMV.
  - jimbokun 16y ago
    That is also an excellent choice. But I believe they are related, or at least complement each other, in the sense that all of the data structure literals implement seq. I do not think they would work as well as an extension for S-expressions, otherwise.
- Xurinos 16y ago
  I am not a CL expert, but I was able to whip this up in short time (and I sacrificed a little readability for brevity): (defun set-hash-values (hash pairs) (when pairs (setf (gethash (car pairs) hash) (cadr pairs)) (set-hash-values hash (cddr pairs)))) (defun in-place-hash (stream char) (declare (ignore char)) `(let ((hash (make-hash-table))) (set-hash-values hash ',(read-delimited-list #\} stream t)) hash)) (set-macro-character #\{ #'in-place-hash) (set-syntax-from-char #\} #\)) But to be honest, I think this {} stuff is an abuse of the hash structure. People are really looking to make quick anonymous classes/structs; you see this all the time in the perl world, and now we get to see this abuse promoted and propagated in Clojure. In that case, {} should really translate to a MOP-generated anonymous class. Also, you are stuck with the decision some developer made for your hash's efficiency trade-offs. In my reader macro, I left things at make-hash-table defaults, but that might not be appropriate for your situation. Do you want to be able to read quickly from your hash in exchange for slow writes, or do you want to be able to write quickly to the hash in exchange for slow reads? On another note, the [] vector reader macro is much easier to create. I just wanted to prove to myself that I could write {}. But this additional syntax is annoying. In practice when programming Lisp, it is easy to slap in a bunch of ))))) until the right alternate parentheses highlights. Now I have to remember to slap in ] and } at the right spots, leaving me with )]}]]}})) noise. Maybe that is why CL's in-place vector syntax is #(). Anyway, I would hesitate to call {} and [] an innovation.
cemerick 16y ago
Note that, unless I'm mistaken, this is from when Clojure emitted Java and C# source. Check out the * host* variable. AFAIK, CL never "hosted" a Clojure runtime.
- parenthesis 16y ago
  Yes, grepping for '(format t ' would seem to confirm this.
bokchoi 16y ago
I came across JFLI a Common-Lisp foreign-language interface to Java and was surprised to find it was authored by Mr. Hickey. I wonder how his experience with JFLI shaped Clojure. http://jfli.sourceforge.net/ http://jfli.sourceforge.net/
nickik 16y ago
To experiment with the language Rich had Clojure Compiler in CL targeting C# and Java. Then he took time off work and wrote the Java bootstrap compiler.

56 points by fogus 16y ago

I read the "early" as pre-release and thought someone was trying to re-implement clojure in CL. I'm relieved. What's the backstory on this, fogus? I've not read about a CL Clojure pre-dating the JVM implementation. Was this just a prototype or was there a plan to platform on CL at some point?

fogus 16y ago
I believe (caveat emptor) that this was an early prototype.

francoisdevlin 16y ago

Does anyone else feel like they're looking at baby pictures?

zachbeane 16y ago
http://www.informatimago.com/develop/lisp/small-cl-pgms/aim-8/aim-8.html http://www.informatimago.com/develop/lisp/small-cl-pgms/aim-...
- alexk7 16y ago
  Now that's "early"! (The link above points to McCarthy texts from 1959 about Lisp)
- fogus 16y ago
  I wonder what happened to Part 2?
  - fogus 16y ago
    I'll answer my own question. McCarthy states in History of Lisp, "Part II was never written but was intended to contain applications to computing with algebraic expressions." Here's hoping he gets around to writing it one day. :-)

KC8ZKF 16y ago

He had DotLisp, a Lisp on the CLR, before Clojure as well. http://dotlisp.sourceforge.net/dotlisp.htm http://dotlisp.sourceforge.net/dotlisp.htm http://groups.google.com/group/comp.lang.lisp/msg/e31b38c8cc0e6a23 http://groups.google.com/group/comp.lang.lisp/msg/e31b38c8cc...

jimbokun 16y ago

I was looking for reader macros for recognizing {} as hash tables and [] as vectors. To me, that is one of the biggest innovations in Clojure over Lisps that came before, the expansion of the concept of S-expressions.

francoisdevlin 16y ago
Personally, my money is on the seq abstraction. YMMV.
- jimbokun 16y ago
  That is also an excellent choice. But I believe they are related, or at least complement each other, in the sense that all of the data structure literals implement seq. I do not think they would work as well as an extension for S-expressions, otherwise.
Xurinos 16y ago
I am not a CL expert, but I was able to whip this up in short time (and I sacrificed a little readability for brevity): (defun set-hash-values (hash pairs) (when pairs (setf (gethash (car pairs) hash) (cadr pairs)) (set-hash-values hash (cddr pairs)))) (defun in-place-hash (stream char) (declare (ignore char)) `(let ((hash (make-hash-table))) (set-hash-values hash ',(read-delimited-list #\} stream t)) hash)) (set-macro-character #\{ #'in-place-hash) (set-syntax-from-char #\} #\)) But to be honest, I think this {} stuff is an abuse of the hash structure. People are really looking to make quick anonymous classes/structs; you see this all the time in the perl world, and now we get to see this abuse promoted and propagated in Clojure. In that case, {} should really translate to a MOP-generated anonymous class. Also, you are stuck with the decision some developer made for your hash's efficiency trade-offs. In my reader macro, I left things at make-hash-table defaults, but that might not be appropriate for your situation. Do you want to be able to read quickly from your hash in exchange for slow writes, or do you want to be able to write quickly to the hash in exchange for slow reads? On another note, the [] vector reader macro is much easier to create. I just wanted to prove to myself that I could write {}. But this additional syntax is annoying. In practice when programming Lisp, it is easy to slap in a bunch of ))))) until the right alternate parentheses highlights. Now I have to remember to slap in ] and } at the right spots, leaving me with )]}]]}})) noise. Maybe that is why CL's in-place vector syntax is #(). Anyway, I would hesitate to call {} and [] an innovation.

cemerick 16y ago

Note that, unless I'm mistaken, this is from when Clojure emitted Java and C# source. Check out the * host* variable. AFAIK, CL never "hosted" a Clojure runtime.

parenthesis 16y ago
Yes, grepping for '(format t ' would seem to confirm this.

bokchoi 16y ago

I came across JFLI a Common-Lisp foreign-language interface to Java and was surprised to find it was authored by Mr. Hickey. I wonder how his experience with JFLI shaped Clojure. http://jfli.sourceforge.net/ http://jfli.sourceforge.net/

nickik 16y ago

To experiment with the language Rich had Clojure Compiler in CL targeting C# and Java. Then he took time off work and wrote the Java bootstrap compiler.