Material Mutation and Transfer

Material mutation uses the << operator to move or merge material into a destination.

target << [source:5uL];

The left side is the destination container. The source list on the right describes material sources and optional transfer quantities.

Quantified Transfer

The minimal public example uses quantified transfer.

target << [source:5uL];

This mutates runtime material state and appears in the execution plan as a material operation.

The quantity must carry a physical unit. This is valid:

target << [source:5uL];

This is not a quantified transfer:

target << [source:1];

Full Transfer

A source item can also be unquantified:

target << [source];

That expresses full-transfer or merge semantics for the source item.

Do not mix quantified and unquantified source items in one transfer statement:

target << [source_a:5uL, source_b];  // invalid style mix

Multiple Sources

Multiple sources can be listed:

target << [sample:80uL, buffer:20uL];

Ordinary source lists mean that multiple sources flow into the same target. They do not imply ordered mapping across a group.

Ordered Mapping with series

For group targets, ordered mapping uses series(...).

group_ref << [series(stock, [5uL, 10uL, 20uL])];

The value list must match the target group size. series(...) is only a mutation source-list form; it is not a general-purpose list mapping expression.

Unit Collection

Culsma also allows collecting a unit back into a container:

keep_tube << [cell];

This is used with stream/unit workflows and belongs to more advanced authoring.

Same-Container No-Op

If a source item resolves to the same container as the target, the item is legal and is treated as a no-op at material execution.

What Transfer Is Not

<< no longer carries a source-level program argument. Actions such as vortexing, shaking, or stirring belong to agit(...), not to transfer syntax.