Re:The most remarkable legacy system I have seen
by FabHK on Monday July 13, 2020 @10:17AM
(#23821016)
> IIRC, it could manage list comprehension but not loops.
If it was like the predecessor system I worked with, it could handle either. But in a list comprehension, it could figure out the individual dependencies of the individual list items.
So, suppose you had a a function that took in a list, and returned a list with some computations performed on each element. If done with list comprehension, and one input element changed, only the corresponding output element would need to be recomputed, and only that would be recomputed.
If done with a loop, and one input element changed, the entire output array would be recomputed (even if all but one element remained unchanged - it would be hard to guarantee that property by code inspection at the time the dependency graph is built).
If it was like the predecessor system I worked with, it could handle either. But in a list comprehension, it could figure out the individual dependencies of the individual list items.
So, suppose you had a a function that took in a list, and returned a list with some computations performed on each element. If done with list comprehension, and one input element changed, only the corresponding output element would need to be recomputed, and only that would be recomputed.
If done with a loop, and one input element changed, the entire output array would be recomputed (even if all but one element remained unchanged - it would be hard to guarantee that property by code inspection at the time the dependency graph is built).