Patternr - experiment with pattern matching

Hi! I’ve created a small application to help learners experiment with pattern matching, It currently supports (a subset of) Elixir and Haskell syntax. I’m happy to hearn any suggestions you may have :slight_smile:

PS: It’s my first app built with LiveView, and the experience has been great!


This looks like a really neat project! I think it would be really helpful to have a couple links that will prefix an example pattern so users can easily see working examples of supported patterns.

Also it would be good if more complex patterns were accepted:

And a minor improvement would be to change “Incorrect Pattern” to “Invalid Pattern”. Incorrect doesn’t really match because you don’t know the users intention.

But overall great job!


Thanks for the comments :slight_smile: I have implemented your suggestions, and the patterns in the image work now.

As an aside: is there a spec of Elixir’s patterns? I could not find a definite spec, only tutorials and more informal descriptions.

Hi, here are some suggestions

  1. case 1..2 does not work

  2. case 1 when x when is_integer(x) -> does not work either (maybe guards are not supported yet)

  3. I would add an end to the the template

case [ TERM ] do
  [ PATTERN ] -> ...

it is kind of confusing that when the header is purple, it is not Elixir, but Haskell. I guess the both use the same color, but that reddish color for Elixir is disguising

Interesting, I’ve always seen orange as the “Elixir color”, maybe because of the several books which use that color. In any case, I’m changing it now to the same background used in Elixir Forums, which is a nice purple :slight_smile:

Thanks for the feedback. I’ve added support for ranges and ‘end’ to finish the block correctly.

That is the Phoenix color :wink:

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Very nice!

Are you planning to implement binaries* and non-atom-keys?

*) Please! Just to tease the Haskellers :nerd_face:

Implementing binary matching is really hard. But my PRs are open :wink: