paulk-asert commented on code in PR #2489:
URL: https://github.com/apache/groovy/pull/2489#discussion_r3143674343
##########
src/test/groovy/gls/statements/MultipleAssignmentDeclarationTest.groovy:
##########
@@ -226,4 +226,1326 @@ final class MultipleAssignmentDeclarationTest {
assert baz == 'baz'
'''
}
+
+ // GEP-20 tail-rest tests
+
+ @Test
+ void testTailRestFromList() {
+ assertScript '''
+ def (h, *t) = [1, 2, 3, 4]
+ assert h == 1
+ assert t == [2, 3, 4]
+ '''
+ }
+
+ @Test
+ void testTailRestWithMultipleHeads() {
+ assertScript '''
+ def (a, b, *rest) = [10, 20, 30, 40, 50]
+ assert a == 10
+ assert b == 20
+ assert rest == [30, 40, 50]
+ '''
+ }
+
+ @Test
+ void testTailRestWithTypedHead() {
+ assertScript '''
+ def (int h, *t) = [1, 2, 3]
+ assert h == 1
+ assert h instanceof Integer
+ assert t == [2, 3]
+ '''
+ }
+
+ @Test
+ void testTailRestFromEmptyList() {
+ assertScript '''
+ def (h, *t) = []
+ assert h == null
+ assert t == []
+ '''
+ }
+
+ @Test
+ void testTailRestFromString() {
+ assertScript '''
+ def (c, *cs) = "hello"
+ assert c == 'h'
+ assert cs == "ello"
+ '''
+ }
+
+ @Test
+ void testTailRestFromIterator() {
+ assertScript '''
+ def (h, t) = [1, 2, 3].iterator() // baseline: same iterator
semantics as existing
+ assert h == 1
+ assert t == 2
+
+ // tail-rest binds the advanced iterator (Path B)
+ def it = [10, 20, 30].iterator()
+ def (head, *tail) = it
+ assert head == 10
+ assert tail instanceof Iterator
+ assert tail.next() == 20
+ assert tail.next() == 30
+ assert !tail.hasNext()
+ '''
+ }
+
+ @Test
+ void testTailRestFromSet() {
+ assertScript '''
+ def s = new LinkedHashSet<>([7, 8, 9])
+ def (sh, *st) = s
+ assert sh == 7
+ def remaining = []
+ while (st.hasNext()) remaining << st.next()
+ assert remaining == [8, 9]
+ '''
+ }
+
+ @Test
+ void testTailRestFromStream() {
+ assertScript '''import java.util.stream.Stream
+ def (first, *rest) = Stream.of('a', 'b', 'c')
+ assert first == 'a'
+ assert rest instanceof Iterator
Review Comment:
These work if that is what you are getting at:
```
def (hs, *ts) = Stream.iterate(0, n -> n + 2)
assert hs == 0 && ts.limit(4).toList() == [2, 4, 6, 8]
def (hi, *ti) = Iterators.iterate(0, n -> n + 2)
assert hi == 0 && ti.take(4).toList() == [2, 4, 6, 8]
```
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
