4 ms·

I feel like the bottom up style is possible in static languages like C++ too, except instead of manually testing small functions in the repl, you can write smal

by klipt 5y ago

I feel like the bottom up style is possible in static languages like C++ too, except instead of manually testing small functions in the repl, you can write small unit tests for them instead. In a way it's even better because a test written once can be run many times, while testing in the repl requires a manual test with every change.

cerved 5y ago
I'm guessing the draw is in the immediate feedback. Like iteratively creating a chain of commands in shell pipe. Compiling and then executing typically takes a minimum of a few seconds before you get feedback
jlarocco 5y ago
That works in Lisp, too though, but it's easier and faster to run the tests in the REPL, so you get the best of both worlds. When I write Lisp I usually start testing in the REPL, iterate until the test code gets to be a few lines long, and then copy it over to the package's unit tests. Then I can keep iterating on both the test code and the code being tested. I'll do something like this in the REPL: (ql:quickload :mylibrary.test) (mylibrary.test:my-test-function) "mylibrary.test" will depend on "mylibrary", so quickload will load both packages when they've been changed, and I can re-run the test quickly using Alt-P to call up the previous REPL input. And the REPL is also really great for "what if" testing that you may not want to keep forever, like, "What happens if I call this function with an invalid parameter?" Hopefully there's a test for that, but it's often a lot faster to just call the function and see what happens rather than go dig through the test code and lose your focus.
gumby 5y ago
This is how I develop in C++, though I am a Lisp programmer
nwallin 5y ago
constexpr and static_assert make this a ton easier in C++. If your "unit tests" are static_asserts, the IDE will just highlight the broken parts. C++17 made this minimally useful, and things got spectacularly better with C++20 and constexpr vector/string. 23 is shaping up to move even more of the standard library to constexpr.
- klipt 5y ago
  I wonder if we'll end up with something like https://www.circle-lang.org/ https://www.circle-lang.org/ which lets you use pretty much the entire C++ runtime language at compile time. It certainly makes heavily templated code way more readable.

by klipt 5y ago

cerved 5y ago

I'm guessing the draw is in the immediate feedback. Like iteratively creating a chain of commands in shell pipe. Compiling and then executing typically takes a minimum of a few seconds before you get feedback

jlarocco 5y ago

That works in Lisp, too though, but it's easier and faster to run the tests in the REPL, so you get the best of both worlds. When I write Lisp I usually start testing in the REPL, iterate until the test code gets to be a few lines long, and then copy it over to the package's unit tests. Then I can keep iterating on both the test code and the code being tested. I'll do something like this in the REPL: (ql:quickload :mylibrary.test) (mylibrary.test:my-test-function) "mylibrary.test" will depend on "mylibrary", so quickload will load both packages when they've been changed, and I can re-run the test quickly using Alt-P to call up the previous REPL input. And the REPL is also really great for "what if" testing that you may not want to keep forever, like, "What happens if I call this function with an invalid parameter?" Hopefully there's a test for that, but it's often a lot faster to just call the function and see what happens rather than go dig through the test code and lose your focus.

gumby 5y ago

This is how I develop in C++, though I am a Lisp programmer

nwallin 5y ago

constexpr and static_assert make this a ton easier in C++. If your "unit tests" are static_asserts, the IDE will just highlight the broken parts. C++17 made this minimally useful, and things got spectacularly better with C++20 and constexpr vector/string. 23 is shaping up to move even more of the standard library to constexpr.

klipt 5y ago
I wonder if we'll end up with something like https://www.circle-lang.org/ https://www.circle-lang.org/ which lets you use pretty much the entire C++ runtime language at compile time. It certainly makes heavily templated code way more readable.