Edge conversions¶

An edge connects an output port on one workflow node to an input port on another. Normally, both ports must have compatible data types. FlowGraph can also accept a connection when it has an explicitly registered, directed automatic conversion.

Available conversions¶

FlowGraph currently provides the following automatic conversions. Rows are source-port types and columns are target-port types. An X marks an explicitly registered automatic conversion; a blank cell has no automatic conversion. Direct connections between compatible types do not require a conversion and are not marked in this table.

Integer → Float converts the integer to a Python float; Integer → Text uses its string representation; and Integer → list[int] wraps the value in a one-item list. Float → Integer rounds to the nearest integer, Float → Text uses the float's string representation, and Float → list[float] wraps the value in a one-item list. filename → Text and Text → filename preserve the value as text while changing its workflow port type.

Vector conversions¶

All four numeric vector types (VEC2D, VEC3D, VEC2DI, and VEC3DI) can connect to one another. The I suffix identifies integer components; the other two types contain floats.

• 2D → 3D: append a third component of 0 for integer targets or 0.0 for float targets.
• 3D → 2D: discard the third component.
• Integer → float: convert each retained component to a Python float.
• Float → integer: round each retained component using Python round, just like the scalar conversion. Halfway values round to the nearest even integer (for example, 1.5 → 2, 2.5 → 2, and -2.5 → -2).

Dimension and component-type changes can happen together. For example, VEC2D [1.2, 2.8] → VEC3DI [1, 3, 0]. Conversions create a new list and leave the source value unchanged. Numeric vectors must contain exactly two or three components according to their declared type. Same-type connections need no conversion.

Conversions are directional. For example, Text → Float is not automatically accepted. A connection without a direct type match or one of the registered conversions is rejected; use an explicit workflow node when a different conversion is required.

Using a converted connection¶

Connect ports normally in the Workflow panel. When FlowGraph applies an automatic conversion:

• the connection is shown in amber instead of the standard edge color;
• selecting the edge in the workflow displays its endpoints and conversion in the Node Inspector; and
• during execution, the target node receives the converted value, validated against its input port type.

For example, an Integer Input value of 4 connected to a Float input delivers 4.0 to the target node. Connecting that float to a Text input then delivers "4.0".

The inspector's transported value is the source output retained by the workflow run result. The Conversion line identifies the transformation applied before the value reaches the target input.

Extending conversion rules¶

Conversion rules are defined centrally in flowgraph.application.port_conversions. Each rule has stable source and target type IDs, a human-readable label, and a conversion callable. Add only deliberate, directed conversions: implicit lossy or ambiguous casts should remain explicit workflow operations.

Workflow JSON stores only edge endpoints. The applicable conversion is resolved from the current source and target port types, so it is applied consistently by validation, execution, edge rendering, and the Node Inspector.