Re: (gen/sample (s/gen #{'nil})): Couldn't satisfy such-that predicate
Hi Alex, > quote is a special form that returns the value you pass it, without evaluation Aah! "without evaluation" is the key! Now it makes sense. Yea you mentioned it before already, but it takes twice the effort to undo and re-comprehend an acquired misconception. Thank you so much! Would you mind if I add this example to http://clojuredocs.org/clojure.core/quote ? It's basically your explanation in the REPL. ;; Quote returns the argument you pass it, without evaluation. So: ;; In the expression `(quote 42)` the argument is the number 42 and... user> (= (quote 42) 42) true ;; ... it is returned without any evaluation and... user> (= (type (quote 42)) (type 42) java.lang.Long) true ;; ... as expected, without changing it's type. ;; In the expression `(quote (quote 42))` the argument is the list of two elements ;; `(quote 42)` and... user> (= (quote (quote 42)) (list (read-string "quote") (read-string "42"))) true ;; ... and it is returned without any evaluation and... user> (= (type (quote (quote 42))) (type (list "1st-elem" "2nd-elem")) clojure.lang.PersistentList) true ;; ... again, without changing it's type. Bost -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: (gen/sample (s/gen #{'nil})): Couldn't satisfy such-that predicate
Go for it. Not sure the type stuff is adding anything in the context of quote examples here beyond the other explanation though. On Thu, Jan 31, 2019 at 6:50 AM Rostislav Svoboda < rostislav.svob...@gmail.com> wrote: > Hi Alex, > > > quote is a special form that returns the value you pass it, without > evaluation > > Aah! "without evaluation" is the key! Now it makes sense. Yea you > mentioned it before already, but it takes twice the effort to undo and > re-comprehend an acquired misconception. Thank you so much! > > Would you mind if I add this example to > http://clojuredocs.org/clojure.core/quote ? > It's basically your explanation in the REPL. > > ;; Quote returns the argument you pass it, without evaluation. So: > ;; In the expression `(quote 42)` the argument is the number 42 and... > user> (= (quote 42) 42) > true ;; ... it is returned without any evaluation and... > user> (= (type (quote 42)) (type 42) java.lang.Long) > true ;; ... as expected, without changing it's type. > > ;; In the expression `(quote (quote 42))` the argument is the list of > two elements > ;; `(quote 42)` and... > user> (= (quote (quote 42)) (list (read-string "quote") (read-string > "42"))) > true ;; ... and it is returned without any evaluation and... > user> (= (type (quote (quote 42))) (type (list "1st-elem" "2nd-elem")) > clojure.lang.PersistentList) > true ;; ... again, without changing it's type. > > > Bost > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to a topic in the > Google Groups "Clojure" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/clojure/K74chBn4Pis/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: (gen/sample (s/gen #{'nil})): Couldn't satisfy such-that predicate
Sometimes text in comments in ClojureDocs.org examples can be more useful than the examples. They are effectively longer (unofficial) doc strings. Andy On Thu, Jan 31, 2019 at 5:36 AM Alex Miller wrote: > Go for it. Not sure the type stuff is adding anything in the context of > quote examples here beyond the other explanation though. > > On Thu, Jan 31, 2019 at 6:50 AM Rostislav Svoboda < > rostislav.svob...@gmail.com> wrote: > >> Hi Alex, >> >> > quote is a special form that returns the value you pass it, without >> evaluation >> >> Aah! "without evaluation" is the key! Now it makes sense. Yea you >> mentioned it before already, but it takes twice the effort to undo and >> re-comprehend an acquired misconception. Thank you so much! >> >> Would you mind if I add this example to >> http://clojuredocs.org/clojure.core/quote ? >> It's basically your explanation in the REPL. >> >> ;; Quote returns the argument you pass it, without evaluation. So: >> ;; In the expression `(quote 42)` the argument is the number 42 and... >> user> (= (quote 42) 42) >> true ;; ... it is returned without any evaluation and... >> user> (= (type (quote 42)) (type 42) java.lang.Long) >> true ;; ... as expected, without changing it's type. >> >> ;; In the expression `(quote (quote 42))` the argument is the list of >> two elements >> ;; `(quote 42)` and... >> user> (= (quote (quote 42)) (list (read-string "quote") (read-string >> "42"))) >> true ;; ... and it is returned without any evaluation and... >> user> (= (type (quote (quote 42))) (type (list "1st-elem" "2nd-elem")) >> clojure.lang.PersistentList) >> true ;; ... again, without changing it's type. >> >> >> Bost >> >> -- >> You received this message because you are subscribed to the Google >> Groups "Clojure" group. >> To post to this group, send email to clojure@googlegroups.com >> Note that posts from new members are moderated - please be patient with >> your first post. >> To unsubscribe from this group, send email to >> clojure+unsubscr...@googlegroups.com >> For more options, visit this group at >> http://groups.google.com/group/clojure?hl=en >> --- >> You received this message because you are subscribed to a topic in the >> Google Groups "Clojure" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/clojure/K74chBn4Pis/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> clojure+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. >> > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
ANN: ClojureScript 1.10.516
ClojureScript, the Clojure compiler that emits JavaScript source code. README and source code: https://github.com/clojure/clojurescript Please refer to the announce post for the details: https://clojurescript.org/news/2019-01-31-release As always, feedback welcome! -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: avoiding casts with aget & friends
Is there any way to inspect what the jit does to it?
On Wednesday, January 30, 2019 at 10:07:38 PM UTC-8, Alex Miller wrote:
>
>
>
> On Wed, Jan 30, 2019 at 11:07 PM Brian Craft > wrote:
>
>> With much experimentation, I ended up with this:
>>
>> (let [a 1
>> b (.longValue ^Long (:foo {:foo 3}))
>> c (if (< a b) a b)])
>>
>> which seems to avoid the longCast call:
>>
>> Object o;
>> if (_thunk__0__ == (o = _thunk__0__.get(const__3))) {
>> o = (__thunk__0__ =
>> __site__0__.fault(const__3)).get(const__3);
>> }
>> final long b = (long)o;
>> final long c = (a < b) ? a : b;
>>
>> I don't know if this is advisable. Does anyone do this?
>>
>
> No, I wouldn't do this. `long` can inline so it's going to be better (it's
> also more likely to jit well as it's used other places and is likely hotter
> in the jit).
>
> Going back to the original...
>
> (let [a 1
> b (:foo {:foo 3})
> c (if (< a b) a b)])
>
> let will track primitives if possible.
> - a is going to be a primitive long.
> - (:foo {:foo 3}) is going to (always) return an Object and it's best to
> recognize that and make an explicit cast to a primitive long.
> - if a and b are both primitives, then < is able to inline a
> long-primitive comparison (via Numbers.lt())
> - the if is going to return an Object though, so again you'll probably
> want to type hint or cast c, but it's hard to know for sure without seeing
> more code
>
> Without other info, I would probably start with
>
> (let [a 1
> b (long (:foo {:foo 3}))
> c (if (< a b) a b)])
>
> Or alternately, it might be better to just type hint b in the comparison
> to avoid reboxing b, but hard to know without more context:
>
> (let [a 1
> b (:foo {:foo 3})
> c (if (< a ^long b) a b)])
>
> Comparing the bytecode for these (skipping everything up through the
> keyword lookup, which is same for all):
>
> Original: Option 1:
>Option 2:
> 45: astore_2 45: invokestatic #41 45:
> astore_2
> 46: lload_0 48: lstore_2
>46: lload_0
> 47: aload_249: lload_0
> 47: aload_2
> 48: invokestatic #41 50: lload_2
> 48: checkcast #37
> 51: ifeq 62 51: lcmp
> 51: invokestatic #43
> 54: lload_0 52: ifge 60
> 54: lcmp
> 55: invokestatic #45 55: lload_0
> 55: ifge 66
> 58: goto 6556: goto 61
> 58: lload_0
> 61: pop 59: pop
> 59: invokestatic #49
> 62: aload_260: lload_2
> 62: goto 69
> 63: aconst_null 61: lstore4
> 65: pop
> 64: astore_2 63: lload 4
>66: aload_2
> 65: astore_3 65: invokestatic #47 67:
> aconst_null
> 66: aload_3
> 68: astore_2
> 67: aconst_null
>69: astore_3
> 68: astore_3
> 70: aload_3
>
> 71: aconst_null
>
> 72: astore_3
>
> Option 1 does an lstore/lload (long) instead of an astore/lstore (object).
> Both options use lcmp which is likely the fastest path to compare longs.
> I've omitted some info here to make these fit, but Original line 48 will
> invoke Numbers.lt:(JLjava/lang/Object;)Z which is the Numbers.lt(long,
> Object) - lcmp is definitely going to be preferable to this. Also of
> importance is that in Option 1, both a and b are stored as longs and loaded
> as longs so if there is subsequent stuff to do on them, they can avoid
> boxing (this is also betrayed by the shorter length from fewer casts).
>
> Your longValue one is like Option 1, but starts:
>
> 45: checkcast #37 // class java/lang/Long
> 48: invokevirtual #41 // Method
> java/lang/Long.longValue:()J
>
> I guess I don't know whether that's faster than an invokestatic call to
> clojure/lang/RT.longCast:(Ljava/lang/Object;)J, hard to tell without
> testing in a real context. I'd certainly use the (long ...) one though
> unless I proved it mattered.
>
>
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Re: avoiding casts with aget & friends
Yes, there a bunch of jvm options to show you when it’s jit-ing, and even the rewritten code. You can google for that stuff like LogCompilation. Occasionally I have found that useful. -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Issue with using keywords as function in a spec conformer
Hi everyone, I have ran into an issue with spec, and suspect it is a bug. The following code throws an error: (clojure.spec.alpha/conformer :foo) The error is a java.lang.Exception and says: Unable to resalve spec; :foo This is unexpected because I intend to use the keyword as a conformer function. An example use-case I would do this is the following (spec/def ::foobar (spec/and (spec/cat :foo int? :bar string?) (spec/conformer :foo))) To show that this is a valid expectation, as a workaround I can wrap the :foo keyword into a lambda, in which case it works: (spec/conformer #(:foo %)) I see that the conformer macro tries to call `res` on the conformer function, which is causing the exception, and I am not sure why needed. I am using Clojure version 1.10.0 -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
