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2 points by akkartik 1415 days ago | link | parent

At least to me, this is expected. The commit you pointed out above switched the null value to '(). The symbol `nil` still evaluates to (). But the need for evaluation implies that it isn't available in contexts that are not evaluated, such as function arguments or in this particular slot of `withs`.

Like I said, happy to revert it if you don't like it. The whole thing came up because of this conversation: https://github.com/arclanguage/anarki/pull/145#issuecomment-.... The motivation was to simplify the Arc implementation. We already have a nil representation in the underlying Racket; it seems unnecessary to so bend over backwards to switch it to something else.



2 points by zck 1415 days ago | link

Let me figure out where in the ecosystem I'm getting the nil value from. I suspect I need to switch a bunch of usages of nil in my codebase to () or '().

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3 points by akkartik 1415 days ago | link

Then again, who knows how long it will take to fix this problem. I'll roll back for now.

Edit: I feared that rolling back may also be non-trivial, but there were only some minor conflicts. Do a `git pull`! All tests are passing, and the bugs here should be fixed now.

Sorry about all this confusion and back-and-forth spanning a year. I'm going to back off on this change now. I think none of us have the bandwidth for a change this radical.

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2 points by zck 1411 days ago | link

Yeah, that seems better. I'm still tracking down two test failures, but they're not because of this. I think templates now are of type 'tem, not type 'table.

I tried to make some changes to () instead of nil, and I was not a big fan of how it looked. I found it very unusual that unless quoted, parentheses mean function application. Letting () be the way to write the empty list (and I believe it worked differently quoted from unquoted, but I'm not sure offhand) completely breaks my mental model of how Lisps are parsed.

But with the revert, things look good. Thanks.

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2 points by akkartik 1411 days ago | link

Great.

What are the two test failures in?

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3 points by zck 1411 days ago | link

As it turns out, it's one test failure (not sure how I got the data into a weird state). It's in the test `tests-are-wrapped-to-create-test-result-template`: https://hg.sr.ht/~zck/unit-test.arc/browse/tests.arc?rev=def...

It's failing because `(type (inst 'foo))` is different in Anarki than Arc. It's a simple change to make it work; I just want to do two things before I stop looking at it:

1. Look deeper into the template inconsistencies. Thanks for the files about this in Anarki. 2. Decide if I want to cut support for Arc, or make this code work in both. This might just involve killing the test, as it's not the _most_ useful test.

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2 points by akkartik 1411 days ago | link

Ouch, have the tests for unit-test.arc been failing for the past year? :( :( Very sorry about that. I see the failure now.

I somehow forgot that unit-test.arc has its own tests. Could you post the instructions for running the tests in the Readme? That would also have the salubrious side effect of showing people a way to run a bunch of existing tests.

Edit: I've added some instructions for running unit-test.arc tests to the Anarki readme: https://github.com/arclanguage/anarki/commit/0913288ec1477f2.... Hopefully that'll help remind me.

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2 points by zck 1410 days ago | link

Don't worry about it! I haven't even run them in a long time, until this week -- I figured I could get teardown functionality working, then remove the hack around running Anarki tests (https://github.com/arclanguage/anarki/blob/master/tests.arc#...).

Thanks for adding the instructions.

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3 points by rocketnia 1407 days ago | link

Once that last one is passing (or maybe even before it's passing), should the top-level tests.arc run these tests too? That way this can be caught not only by Travis CI, but also by people running tests.arc according to the readme.

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2 points by zck 1407 days ago | link

Good question. I guess it's a question of if we have enough Anarki tests to minimze breaking changes.

If we do, then I don't know if it matters if we run unit-test.arc tests -- it's just one Arc library, presumably of several.

It's a little different than other libraries because it's what we use for Anarki unit tests.

Running it as part of Anarki's unit tests would prevent breakage, and is a simple solution to get a lot more tests added to the language. Anyone want to write a bunch of tests for Anarki itself?

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3 points by akkartik 1407 days ago | link

Anarki isn't really intended to avoid or minimize breaking changes. The unit tests verify only that everything is internally consistent. That boundary around 'internal' should include unit-test.arc, I think.

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3 points by krapp 1412 days ago | link

Is the problem the equality between nil and the empty list, or did that just expose some unknown flaw with the way Arc deals with macros?

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3 points by zck 1409 days ago | link

I _think_ it's some weirdness with the nil/empty list thing. I was getting a case where (str x) resulted in the string "nil", but whatever that object was was not treated as nil, for example in conditionals.

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