Migrating code examples to the new compiler · contributing

Stream: contributing

Topic: Migrating code examples to the new compiler

Aurélien Geron (Jul 31 2026 at 11:10):

I created a draft PR to migrate all the code examples to the new compiler. I started by migrating all the code examples that can run on the echo platform, without any library dependency. That's 19 examples so far:

AllSyntax (just copied the all-syntax example)
BasicDict
CommandLineArgs (there's a bug if you run roc build, see issue #10492)
CustomInspect
ErrorHandlingBasic
FizzBuzz
GraphTraversal
HelloWorld
ImportFromDirectory (will probably require changes soon, see @Luke Boswell 's proposal)
IngestFiles
Json
LeastSquares
MultiLineComments (no change was required)
MultipleRocFiles
PatternMatching
SafeMath (note: Dec.times_try is missing)
TowersOfHanoi
TryOperatorDesugaring
Tuples

The only echo-platform-only example remaining is EncodeDecode, but I'm not sure how to handle this one.

If anyone wants to help migrate the rest, please let me know!

Aurélien Geron (Jul 31 2026 at 11:33):

Below are the remaining examples to migrate.

The following depend on basic-cli (e.g., cli.File or cli.Cmd), and sometimes on other libraries as well (e.g., rand, unicode, ...):

ImportPackageFromModule => basic-cli + unicode lib
CommandLineArgsFile => basic-cli (File)
Commands => basic-cli (Cmd)
ErrorHandlingRealWorld => basic-cli (Env, Http, Dir, Utc, Path)
LoopEffect => basic-cli (Stdin)
Parser => basic-cli + parser
RandomNumbers => basic-cli + rand
Snake => basic-cli (Tty)
SortStrings => basic-cli + ascii

The following are integrations. I have no idea how to do this:

DotNetPlatform => integrate with DotNet
GoPlatform => Integrate with Go

The following depend on the web platform:

ElmWebApp
HelloWeb

Others:

Scripting => points to several external scripts. Not sure whether there's a plan to migrate them.
RecordBuilder => uses the <- syntax which doesn't exist anymore. What should we do?
EncodeDecode => should work on the echo platform, but I'm not sure how to do this.

Aurélien Geron (Aug 03 2026 at 05:53):

I migrated 7 more examples. 26 down, 9 to go!

The following remaining examples are tricky:

RandomNumbers: requires migrating the roc-random library. It looks like it's almost done, right?
SortStrings: requires migrating the roc-ascii library. Or perhaps using the unicode library instead?
DotNetPlatform => somehow integrate with DotNet. How?
GoPlatform => somehow integrate with Go. How?
Scripting => points to several external scripts. Have they been migrated somewhere?

The following shouldn't be too hard:

RecordBuilder => use the new builder syntax
ElmWebApp => use the basic-web platform
HelloWeb => use the basic-web platform
EncodeDecode => should be straightforward.

Luke Boswell (Aug 03 2026 at 05:55):

This is the one you want now https://github.com/kili-ilo/roc-random -- it's been getting a lot of love recently from @Austin Clements

Luke Boswell (Aug 03 2026 at 05:56):

I'd drop DotNet and Go for now (or deprecate them until we have support for those). In theory I could probably figure it out but I'm already spread so thin I'm not about to start that.

Luke Boswell (Aug 03 2026 at 05:57):

I'd drop Scripting too for now

Luke Boswell (Aug 03 2026 at 05:58):

@Hannes would you mind porting roc-ascii?

Aurélien Geron (Aug 03 2026 at 06:06):

Migrated the RandomNumbers example. The rand library works like a charm! :grinning:

Hannes (Aug 03 2026 at 06:36):

I have a version of roc-ascii updated to the new compiler locally, just haven't got round to cleaning it up and pushing it yet, i'll see if I can get something out this week :)

Luke Boswell (Aug 03 2026 at 06:37):

Legendary

Aurélien Geron (Aug 03 2026 at 22:29):

I'm hitting a few issues for the 5 remaining examples:

EncodeDecode: I'm running into a segfault, see issue #10584
RecordBuilder: I haven't been able to get even a super minimal example of the new { ... }.Foo + map2 syntax working. I'm too too dumb for record builders! :sweat_smile:
SortStrings: needs the roc-ascii library, @Hannes is on it :+1:
HelloWeb: there seems to be something wrong with basic-webserver, see issue #10586
ElmWebApp: same. Btw, wouldn't it be a good idea to have a Wasm example as well, so both the frontend and backend are written in Roc?

Edit: I finally understood record builders. I've posted a minimal example if anyone else is struggling.

Anton (Aug 04 2026 at 11:44):

wouldn't it be a good idea to have a Wasm example as well, so both the frontend and backend are written in Roc?

Should we just use joy here?

Aurélien Geron (Aug 05 2026 at 11:17):

Just 3 examples to go: SortStrings, HelloWeb, and ElmWebApp. Perhaps we can put the rest of the examples online already, and add these three when they're ready?

Anton (Aug 05 2026 at 11:21):

Yes, I will try to review https://github.com/roc-lang/examples/pull/258 today

Niclas Ahden (Aug 05 2026 at 11:24):

@Aurélien Geron Let me know if I can help out with Joy, and I'd love to hear what you think of it and any issues you may run into! I'm chronically Roc'y, so just @ me :)