[jira] [Comment Edited] (GROOVY-10666) Implement multiple-assignment (aka destructuring) via getAt(IntRange) when supported

["Eric Milles (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/GROOVY-10666?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17558932#comment-17558932 ] 

Eric Milles edited comment on GROOVY-10666 at 6/26/22 11:22 PM:
----------------------------------------------------------------

{code:groovy}
class MySet {
  @Delegate Set<String> strings = []
  String getAt(int index) {
    println("getAt($index)")
    DefaultGroovyMethods.getAt(this, index)
  }
  Iterator<String> iterator() {
    println "iterator()"
    def iterator = strings.iterator()
    new Iterator<String>() {
      @Override
      boolean hasNext() {
        println "next()"
        iterator.hasNext()
      }
      @Override
      String next() {
        iterator.next()
      }
    }
  }
}
Set<String> strings = new MySet()
strings << 'foo'
strings << 'bar'
strings << 'baz'

def (foo, bar, baz) = strings
{code}

Outputs:
{code}
getAt(0)
iterator()
next()
getAt(1)
iterator()
next()
next()
getAt(2)
iterator()
next()
next()
next()
{code}


was (Author: emilles):
{code:groovy}
class MySet {
  @Delegate Set<String> strings = []
  Iterator<String> iterator() {
    println "iterator()"
    def iterator = strings.iterator()
    new Iterator<String>() {
      @Override
      boolean hasNext() {
        println "next()"
        iterator.hasNext()
      }
      @Override
      String next() {
        iterator.next()
      }
    }
  }
}
Set<String> strings = new MySet()
strings << 'foo'
strings << 'bar'
strings << 'baz'

def (foo, bar, baz) = strings
{code}

Outputs:
{code}
iterator()
next()
iterator()
next()
next()
iterator()
next()
next()
next()
{code}

> Implement multiple-assignment (aka destructuring) via getAt(IntRange) when supported
> ------------------------------------------------------------------------------------
>
>                 Key: GROOVY-10666
>                 URL: https://issues.apache.org/jira/browse/GROOVY-10666
>             Project: Groovy
>          Issue Type: Improvement
>          Components: groovy-jdk
>            Reporter: Eric Milles
>            Assignee: Eric Milles
>            Priority: Minor
>
> Currently multiple-assignment is implemented using {{getAt(int)}}.  For types that support {{getAt(IntRange)}} it may be more efficient to use that operation.  For cases where {{getAt(int)}} is a terminal operation (aka streams) it may be the only way to go.
> Consider the following:
> {code:groovy}
> Set<String> set = ['foo','bar','baz']
> def (foo, bar, baz) = set // inefficient; requires 3 iterators and 6 calls to next
> Stream<String> stream = ['foo','bar','baz'].stream()
> def (foo, bar, baz) = stream // not possible because `getAt(int)` is terminal
> {code}



--
This message was sent by Atlassian Jira
(v8.20.7#820007)