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Hi Chris You wrote: In fact, on subsequent consideration, I'm inclining more strongly
towards SyntaxError, due to the difficulty of explaining the actual semantics. Changing the PEP accordingly.
Your PEP, so your choice. I now think that if implemented, your PEP adds to the Python compiler (and also runtime?) tools for detecting and well-ordering Directed Acyclic Graphs (DAG). Here's another problem. Suppose def puzzle (*, a=>..., z>=...) gives rise to a directed acyclic graph, and all the initialisation functions consume and use a value from a counter. The semantics of puzzle will now depend on the linearization you choose for the DAG. (This consumption and use of the value from a counter could be internal to the initialisation function.) -- Jonathan