I want to use typing rules for typing siblings in an AST, not simply a node by its children.

Use case:

Edge(node1, edge, node2)

Edge(LeftHand(node1, edge), node2)

The second case I can have a type rule for LeftHand and use it to do something with node2 or the Edge as a whole.

But I’d rather have the possibility to do the same with the first AST.

Is there a theoretical reason to only support upwards typing as opposed to typing rules for sibblings or downwards?

Submitted by Daco Harkes on 29 November 2014 at 18:16