Reply To: Understanding causality errors when using `pre` and `last` in a Scade program.

[Benjamin Descorps]

Hello,

Actually, in your model, the activate block compute the output y. But activation of the activate block also depends on the variable y. This leads to a causality error.

If you want to resolve this error, you should add a delay. Example:

type T = enum {a, b, c};

node WhenBlkSample(x: T) returns (y: T last = b)

let

  activate when last 'y match

  | a: y = a -> pre(y);

  | b: y = x;

  | c: -- empty

  returns ..;

tel