LazySequence methods
A lazy sequence generates and caches values on demand. It is not itself a cursor: call Iterator() for an independent traversal position.
Method reference
| Full syntax | Result | Meaning |
|---|---|---|
sequence.Len() |
Integer |
Return a known eventual length without forcing all values; error if still unknown. |
sequence.IsEmpty() |
1 \| null |
Generate at most the first output to determine emptiness. |
sequence.Get(index) |
any \| null |
Generate through a positive one-based index; a negative index materializes a finite source. |
sequence.First() |
any \| null |
Generate and return the first value. |
sequence.Last() |
any \| null |
Materialize a known finite source and return its last value. |
sequence.Materialize() |
Array |
Evaluate a known finite sequence completely. |
sequence.Iterator() |
Iterator |
Create a cursor sharing the source cache. |
sequence.CheckTraits() |
1 \| null |
Validate attached semantic traits. |
Checked examples
s := [3 |+ 3 |^ 5];
s.Len() ##@ == 5;
s.IsEmpty() ##@ == _;
s.Get(3) ##@ == 9;
s.First() ##@ == 3;
s.Last() ##@ == 15;
s.Materialize().Join() ##@ == "3,6,9,12,15";
unbounded := [1 |+ 1];
unbounded.Get(100) ##@ == 100;
it := unbounded.Iterator(); it.Next(3) ##@ == 3;
s.CheckTraits() ##@ == 1;Last, negative indexing, and Materialize require a known finite sequence. A predicate-bounded source becomes known only after generation reaches its terminating value.