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https://issues.apache.org/jira/browse/GROOVY-7772?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15177489#comment-15177489
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UEHARA Junji edited comment on GROOVY-7772 at 3/3/16 8:45 AM:
--------------------------------------------------------------
Sorry No 3 is wrong. It should be:
|3|instance|staticMethod| { ..args -> Class.staticMethod(args) } | same as
groovy |
You mentioned semantics with closure and curry(), I think that is:
{code}
x.&y
== if x instanceof Class && y is_not_static_method then
{xarg, args... -> xarg.y(args)}
else
{xarg, args... -> xarg.y(args)}.curry(x)
{code}
for confirmation,
{code}
"abc".&toUpperCase() // Instance.&instanceMethod (No 1)
== {xarg, args... -> xarg.toUpperCase(args)}.curry("abc")()
== {args... -> "abc".toUpperCase(args)}()
== {->"abc".toUpperCase()}()
== "abc".toUpperCase()
== "ABC"
Integer.&parseInt("123") // Class.&staticMethod (No 2)
== {xarg, args... -> xarg.parseInt(args)}.curry(Integer)("123")
== {args -> Integer.parseInt(args)}("123")
== Integer.parseInt("123")
== 123
3.&parseInt("123") // Instance.&staticMethod (No 3)
== {xarg, args... -> xarg.parseInt(args)}.curry(3)("123")
== {args... -> 3.parseInt(args)}("123")
== 3.parseInt("123")
== 123
String.&toUpperCase("abc") // Class.&instanceMethod (No 4)
== {xarg, args... -> xarg.toUpperCase(args)}("abc")
== "abc".toUpperCase()
== "ABC" // this is My proposal behavior, Current groovy treat this as error.
{code}
was (Author: uehaj):
Sorry No 3 is wrong. It should be:
|3|instance|staticMethod| { ..args -> Class.staticMethod(args) } | same as
groovy |
You mentioned semantics with closure and curry(), I think that is:
{code}
x.&y
== if x instanceof Class && y is_not_static_method then
{xarg, args... -> xarg.y(args)}
else
{xarg, args... -> xarg.y(args)}.curry(x)
{code}
for confirmation,
{code}
"abc".&toUpperCase()() // Instance.&instanceMethod (No 1)
== {xarg, args... -> xarg.toUpperCase(args)}.curry("abc")()
== {args... -> "abc".toUpperCase(args)}()
== {->"abc".toUpperCase()}()
== "abc".toUpperCase()
== "ABC"
Integer.&parseInt("123") // Class.&staticMethod (No 2)
== {xarg, args... -> xarg.parseInt(args)}.curry(Integer)("123")
== {args -> Integer.parseInt(args)}("123")
== Integer.parseInt("123")
== 123
3.&parseInt()("123") // Instance.&staticMethod (No 3)
== {xarg, args... -> xarg.parseInt(args)}.curry(3)("123")
== {args... -> 3.parseInt(args)}("123")
== 3.parseInt("123")
== 123
String.&toUpperCase()("abc") // Class.&instanceMethod (No 4)
== {xarg, args... -> xarg.toUpperCase(args)}("abc")
== "abc".toUpperCase()
== "ABC" // this is My proposal behavior, Current groovy treat this as error.
{code}
> Class.&instanceMethod had better to have same meaning of
> Class::instanceMethod of Java8
> ---------------------------------------------------------------------------------------
>
> Key: GROOVY-7772
> URL: https://issues.apache.org/jira/browse/GROOVY-7772
> Project: Groovy
> Issue Type: Improvement
> Components: groovy-runtime
> Affects Versions: 2.4.6
> Reporter: UEHARA Junji
> Priority: Minor
>
> Groovy's operator .& for method is similar functionality to Java8's method
> reference operator ::.
> ||No.||lhs||rhs||meaing of Groovy's .& (Closure) ||meaning of java8's ::
> (FunctionalInterface)||
> |1|instance|instanceMethod| { ..args -> instance.instanceMethod(args) | same
> as groovy |
> |2|Class|staticMethod| { ..args -> Class.staticMethod(args) | same as groovy |
> |3|instance|staticMethod| ERROR groovy.lang.MissingMethodException: | Error
> same as groovy (compile error) |
> |4|Class|instanceMethod|error| Function<RetType,Class,Args..>, where method
> instance method of Class which is declared as ```RetType
> instanceMethod(Args..) {...}```. In other words it is interpreted as a
> function which takes LHS Class as the first parameter which additionally
> inserted to the method.)|
> IMHO, i'd like to propose to change the No 4 pattern semantics of groovy
> same as Java 8 's. Because:
> * You can write:
> {code}
> ["a,b,c"].collect ( String.&toUpperCase )
> {code}
> instaed of
> {code}
> ["a,b,c"].collect { it.toUpperCase() }
> {code}
> * Can have correspond operator to java8's ::. which is understandablea and
> needed for Java programmers.
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