Stream: roctoberfest

Topic: Random

jan kili (Oct 01 2022 at 14:19):

Whoa! Either I don't understand how Zulip works or Roctoberfest is a smash hit!
Screen-Shot-2022-10-01-at-8.17.59-AM.png

jan kili (Oct 01 2022 at 14:19):

Either way, it beginssssssssssss :nerd:

Anton (Oct 01 2022 at 14:20):

I invited everyone to the stream because it is easy to miss a new stream otherwise.

Gabriel Pickl (Oct 02 2022 at 22:05):

Uuuh?

This True tag has the type:

    [True]a

But count needs its 2nd argument to be:

    Bool

for reference, the signature is count : List a, a -> Nat, which I'm using to count the number of depth increases in example one.
The error message makes me assume that True is interpreted as a closed single tag? Do I need to manually import True?

Zeljko Nesic (Oct 02 2022 at 22:06):

I think that you need to say explicitly Bool.True

Gabriel Pickl (Oct 02 2022 at 22:07):

I am trying to parse a qualified name here:

27│      |> count Bool.True
                           ^

This looks like a qualified tag name to me, but tags cannot be
qualified! Maybe you wanted a qualified name, something like
Json.Decode.string?

Brendan Hansknecht (Oct 02 2022 at 22:08):

So this was a recent change where they made bools into opaque types. Should be True to Bool.true

Brendan Hansknecht (Oct 02 2022 at 22:08):

Lowercase T in the second example

Gabriel Pickl (Oct 02 2022 at 22:11):

that works. I remember seeing somewhere that true was lowercase, but using it without prefix didn't work so I defaulted to the syntax mentioned in the current docs
It also feels a bit strange to have user-defined tags be upper camelcase, but not Bool values. although I gotta say that roc is not the only language that does that, so :shrug:

Brendan Hansknecht (Oct 02 2022 at 22:13):

So internally, there is a statement in the Bool module that is essentially:

Export true

true = True

Once save as a variable, it is no longer capatilized because variable must start with a lowercase letter.

Brendan Hansknecht (Oct 02 2022 at 22:14):

But yeah, i get the confusion

Gabriel Pickl (Oct 02 2022 at 22:22):

fair, that's consistent, just a bit confusing coming from Elm

Gabriel Pickl (Oct 02 2022 at 22:22):

might be something the compiler could drop a hint about to prevent some headscratching

Richard Feldman (Oct 02 2022 at 22:25):

oops, yeah I need to update the tutorial to explain this :sweat_smile:

Richard Feldman (Oct 02 2022 at 22:26):

tl;dr use Bool.true and Bool.false instead of True and False and everything should work out!

Shritesh Bhattarai (Oct 03 2022 at 18:25):

Unlike what the doc says, Str.graphemes does not exist :sweat_smile:

Mike Kalvas (Oct 03 2022 at 23:06):

Ran into this too. Can workaround it using toUtf8 for simple stuff but it would be great to have that function.

Anton (Oct 04 2022 at 10:50):

@Shritesh Bhattarai where is Str.graphemes mentioned?

Ghislain (Oct 04 2022 at 10:58):

https://github.com/roc-lang/roc/blob/f6c981294a8389b0583d9b81813fbb44b581f782/crates/compiler/builtins/roc/Str.roc#L157

Kilian Vounckx (Oct 05 2022 at 07:01):

Mike Kalvas said:

Ran into this too. Can workaround it using toUtf8 for simple stuff but it would be great to have that function.

You could use toScalars as well. It returns a List U32 where each element represents the unicode code point of a character

jan kili (Oct 07 2022 at 06:16):

FYI, @Ayaz Hafiz just added positional arguments to examples/interactive/cli-platform! Passing primary+required information (like the path to your input data file?) should be much simpler now - let us know if it's broken or awesome!

jan kili (Oct 07 2022 at 19:40):

The CLI platform directory in the Roc repo will be moving today! (We're simplifying the organization of examples :smile:) If you update your clone of the Roc repo, then you'll need to update your apps' platform path, too.

Last updated: Jul 26 2025 at 12:14 UTC