Re:Generalizing 'jq' and Traversal Systems using optics and ...
by ben509 on Thursday October 08, 2020 @03:00PM
(#24722507)
> Not all functional languages have static typing.
Even the multi-paradigm, late-bound languages that are adding functional programming are adding static typing, e.g. TypeScript and mypy.
> No type checker will catch this error...
Sure, math is hard. In the domain of structural transformations, one's intuition combined with a decent type checker really does work, though.
Especially, I've done large refactorings of complex transformations, tracked down the typing errors, and then been pleasantly surprised when my test-suites passed the first time.
> sqrt :: double -> double
I can use QuickCheck[1]:
prop_Sqrt_Sqr n = sqrt n * sqrt n == abs n
Because it can exploit the type system, it can then plug in various values of Double to see if squaring my square root squares properly.
Even the multi-paradigm, late-bound languages that are adding functional programming are adding static typing, e.g. TypeScript and mypy.
> No type checker will catch this error...
Sure, math is hard. In the domain of structural transformations, one's intuition combined with a decent type checker really does work, though.
Especially, I've done large refactorings of complex transformations, tracked down the typing errors, and then been pleasantly surprised when my test-suites passed the first time.
> sqrt :: double -> double
I can use QuickCheck[1]:
Because it can exploit the type system, it can then plug in various values of Double to see if squaring my square root squares properly.[1]: http://www.cse.chalmers.se/~rjmh/QuickCheck/manual.html