dippim wrote:
will say that as this particular requirement is imposed on this class
by the writer, shouldn't it be the writer's responsibility to enforce
it, especially, when the cost of enforcement is so low?
I would say that it is the writer's responsibility to set the
requirement and be clear as to what it is and define the contract with
respect to the requirement. The latter could either be user
responsibility -- behavior explicitly undefined if violated -- or writer
responsibility -- with either fix or raise exception upon violation
detection.
Python's duck-typing style tends to put responsibility on callers. Consider
def minmidmax(seq):
seq.sort()
n = len(seq)
return seq[0], seq[n//2], seq[n-1]
This requires that seq have sane .sort, .__len__, and .__getitem__
methods. Checks could be added, but most Python programs would simply
say the the input must be an in-place sortable sequence.
Terry Jan Reedy
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