On Wed, Jan 21, 2009 at 10:29 AM, Mark Volkmann
<[email protected]> wrote:
>
> What does "321" represent?
user=> (show 321 :bridge)
=== public final java.lang.Integer ===
[32] compareTo : int (Object)
nil
321 is an Integer literal. When 'show' sees a non-class as its first
argument, it fetchs the object's class and operates on that instead.
Hence the banner line that says "public final java.lang.Integer"
This is useful when you're not sure what class you're actually dealing
with, and are too lazy to type "(class " and ")" yourself:
user=> (show 42M "pow")
=== public java.math.BigDecimal ===
[69] pow : BigDecimal (int)
[70] pow : BigDecimal (int,MathContext)
[76] scaleByPowerOfTen : BigDecimal (int)
nil
Look, it's a BigDecimal! Hm, I wonder if hash-maps have a run()
method:
user=> (show {} "run")
=== public clojure.lang.PersistentArrayMap ===
[56] run : void ()
nil
Wait, that's not a hash-map, it's an array-map. And it does have a
run(), though I can't imagine how I'd use it. But what about a real
hash-map, does it have any methods that take variable arguments?
user=> (show (hash-map) :varArgs)
=== public clojure.lang.PersistentArrayMap ===
[44] invoke : Object (Object*20,Object[])
nil
There's that array-map again. Let's try the class explicitly, then:
user=> (show clojure.lang.PersistentHashMap :varArgs)
=== public clojure.lang.PersistentHashMap ===
[ 3] static create : PersistentHashMap (IPersistentMap,Object[])
[ 6] static create : PersistentHashMap (Object[])
[45] invoke : Object (Object*20,Object[])
nil
Ah, much better. But that was too much to type. Next time I'm going
to use (hash-map :a 1) instead. Maybe it has a method that returns a
boolean:
user=> (show (hash-map :a 1) #(= (:returnType %) Boolean/TYPE))
=== public clojure.lang.PersistentHashMap ===
[15] containsKey : boolean (Object)
[16] containsValue : boolean (Object)
[21] equals : boolean (Object)
[22] equiv : boolean (Object)
[48] isEmpty : boolean ()
nil
Oh, I wonder if that containsKey() method is public. It's marked as
number [15], so:
user=> (show (hash-map :a 1) 15)
#<Method public boolean
clojure.lang.PersistentHashMap.containsKey(java.lang.Object)>
Good, it *is* public... and so on...
--Chouser
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