Give me a better one then.
I need a way for quickly annotating loops with invariants. The problem
with context managers is that it needs indentation change which is
definitely not "quick".
Imagine I wanted to take code from some public repo and add loop
invariants to it. If the diff touches half of the lines of the code, it
will never be merged.
We can quickly annotate functions with decorators and type hints (both
are one-liners).
We can quickly specify assertions (one-liner).
Now give me one-liner for loop invariants.
On 11/04/20 10:20 am, haael wrote:
class InvariantError(AssertionError):
pass
def loop_invariant(condition:bool):
if not condition:
raise InvariantError
return True
for element in iterable if loop_invariant(condition):
loop_body
That's a *very* misleading way to check loop invariants,
because it makes it look like a filter rather than an
invariant check.
Also it doesn't quite do a complete job, because it
doesn't check the invariant after the last iteration,
and doesn't check it at all if the iterable is empty.
while loop_invariant(condition) and running:
loop_body
Again misleading, because it looks like part of the
loop condition.
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