Group Templates

Flowno supports reusable subgraphs through template groups. A template is defined with @node.template and behaves like a function that builds a small FlowHDL snippet. The first parameter must be a FlowHDLView which provides the temporary context used to create nodes inside the group.

The template should return one of the nodes it defines. When the surrounding FlowHDL context is finalized the DraftGroupNode produced by calling the template is replaced by that return value, leaving no trace of the template at runtime.

Example

from flowno import node, FlowHDL, FlowHDLView

@node
async def Inc(x: int) -> int:
    return x + 1

@node.template
def IncTwice(f: FlowHDLView, x: int):
    f.first = Inc(x)
    f.second = Inc(f.first)
    return f.second

with FlowHDL() as f:
    f.result = IncTwice(1)

f.run_until_complete()
print(f.result.get_data())

(3,)

Template groups may accept multiple inputs and default values just like normal @node functions. Groups can also be nested, allowing complex flows to be composed from smaller pieces.