refs.listshape

Module nustd.kv.refs.listshape.

Virtuals shapes list reference: sequence of homogeneous shapes.

Index descent (ref[i]) is overridden to return a substrate-backed virtuals ShapeRef at the index, with this ref as parent_ref.

Name	Sort	Call	Meaning
ShapesListRef	`ref`	`ShapesListRef(address, shape_type, view_type=None, parent_ref=None, owner_shape=None)`	An ordered list of one shape type in KV storage, indexed into by position.

ShapesListRef

An ordered list of one shape type in KV storage, indexed into by position.

ShapesListRef(address, shape_type, view_type=None, parent_ref=None, owner_shape=None)

Path nustd.kv.ShapesListRef. Kind Ref, sort ref, cardinality scalar.

Indexing lands on a shape ref at that position rather than on a value, so a row's fields are reachable and writable one at a time: rows[0].symbol.set(...).

Notes

Every row is stored decomposed, field by field, so writing one field of one row does not read or rewrite the others.
A position does not vivify: writing a field at an index the list does not reach raises IndexError. Grow the list first, by appending the row or setting the whole list.
Reading a field at an out-of-range index is not an error; it yields EMPTY.
The index may be an expression or a ref, so the position can be computed at run time.
ListRef is the sibling for lists of plain values.

Example

class Order(Shape):
    symbol = StrRef.slot()
class Portfolio(Shape):
    orders = ShapesListRef.slot(Order)
run(Portfolio.orders.append({"symbol": "SOL"}), ctx)
run(Portfolio.orders[0].symbol, ctx)

Inherited methods

From nu.forms.collections.abc.sequence.ReactiveSequenceForm:

Call	Builds	Meaning
`.on_change()`	`object`	Subscribe to any change on this sequence slot.

From nu.forms.collections.abc.sequence.MutableSequenceForm:

Call	Builds	Meaning
`.append(value)`	`Any`	Append value to the end of self.
`.extend(other)`	`Any`	Extend self with the elements of other, in order.
`.insert(index, value)`	`Any`	Insert value at index, shifting later elements right.
`.pop(index=-1)`	`ElementResultT`	Remove and return the element at index.
`.del_at(index)`	`Any`	Remove the element at index.
`.remove(value)`	`Any`	Remove the first occurrence of value.
`.reverse()`	`Any`	Reverse self in place.
`.sort()`	`Any`	Sort self in place, ascending, using the elements' natural order.
`.copy()`	`CollectionResultT`	Shallow copy of self: a new sequence with the same elements.
`.clear()`	`Any`	Remove every element from self.

From nu.domains.shape.refs.shapes_sequence.ShapesSequenceRef:

Call	Builds	Meaning
`a[key]`	`ItemResultT`	Int index navigates to the child ShapeRef; slice routes to the form-level slice op.

From nu.forms.collections.abc.sequence.SequenceForm:

Call	Builds	Meaning
`.first_elem()`	`ElementResultT`	First element of self.
`.last_elem()`	`ElementResultT`	Last element of self.
`.index(value)`	`Int`	Lowest index in self where value is found, searching from the left.
`.count(value)`	`Int`	Count of occurrences of value in self.
`.reversed()`	`CollectionResultT`	Self walked back to front, as a stream.

From nu.forms.collections.abc.collection.CollectionForm:

Call	Builds	Meaning
`.extract()`	`object`	Materialise the full subtree rooted at self.

From nu.forms.collections.abc.sized.SizedForm:

Call	Builds	Meaning
`.len()`	`Int`	Length of self.

From nu.forms.collections.abc.iterable.IterableForm:

Call	Builds	Meaning
`iter(a)`	`Iterator[ElementT]`	Open self into a lazy iterator stream (Python's `iter`).

From nu.forms.collections.abc.container.ContainerForm:

Call	Builds	Meaning
`.contains(item)`	`Bool`	Whether item is a member of self.

From nu.forms.collections.abc.sliceable.SliceableForm:

Call	Builds	Meaning
`.slice(start, stop, step=None)`	`ResultT`	Slice of self from start to stop, stepping by step.

From nu.domains.shape.forms.collection.ReactiveCollectionForm:

Call	Builds	Meaning
`.on_child_change(address)`	`OnChildChange`	Observe changes at a specific child address.
`.on_children_change()`	`OnChildrenChange`	Observe changes across all direct children.
`.on_descendants_change()`	`OnDescendantsChange`	Observe changes across descendants matching `pattern`.

From nu.domains.shape.forms.collection.MutableCollectionForm:

Call	Builds	Meaning
`.set(value)`	`SetCmd`	Build a `SetCmd`.
`.erase()`	`Erase`	Build an `Erase`.
`.init(value)`	`IfDo`	Set `value` iff the collection is currently missing.

From nu.domains.shape.forms.collection.CollectionForm:

Call	Builds	Meaning
`.exists()`	`Exists`	Build an `Exists` query.
`.missing()`	`Missing`	Build a `Missing` query.

From nu.lang.forms.Form:

Call	Builds	Meaning
`.is_empty()`	`Bool`	True if this Form yields the EMPTY sentinel.
`.is_invalid()`	`Bool`	True if this Form yields the INVALID sentinel.
`.is_sentinel()`	`Bool`	True if this Form yields either sentinel (EMPTY or INVALID).
`.not_empty()`	`Bool`	True if this Form does not yield EMPTY.
`.not_invalid()`	`Bool`	True if this Form does not yield INVALID.

refs.listshape

ShapesListRef

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