Better error message for triple equals

[rabingaire]

fix: #3125

This is the new error message after the fix:

error: Syntax error
  ┌─ /Users/rabingaire/Desktop/test_app/src/test_app.gleam:4:37
  │
4 │   [1,2,3] |> list.filter(fn (a) { a === 3 }) 
  │                                     ^^^ Did you mean `==`?

Gleam uses `==` to check for equality between two values.
See: https://tour.gleam.run/basics/equality

[lpil]

Thank you. Could you add a test to ensure that this code does not result in that helpful error:

==     =

I think currently it will show the error in this case, which isn't what we want.

It may be better to implement this in the tokeniser rather than in the parser.

[rabingaire]

Thank you. Could you add a test to ensure that this code does not result in that helpful error:

==     =

I think currently it will show the error in this case, which isn't what we want.

It may be better to implement this in the tokeniser rather than in the parser.

Thank you for the recommendation, I made the changes and now the logic is handled in tokenizer, let me know if the error message is good enough, if it is not we can add a special case like these

LexicalErrorType::UnrecognizedToken { tok } if *tok == '\'' => (
    "Unexpected single quote",
    vec!["Hint: Strings are written with double quotes.".into()],
),

[lpil]

Hello! I gave this a try and I got this error:

error: Syntax error
  ┌─ /Users/louis/Desktop/thing/src/thing.gleam:4:5
  │
4 │   ===
  │     ^ I can't figure out what to do with this character

Hint: Is it a typo?

This doesn't seem any clearer to me than the previous error. Let's have one like Giacomo suggested in the issue, that'll help the programmer understand what the problem is.

I also tested with == = and I got the same error, but it should have the original error and the new error should only be for ===

[rabingaire]

Hello! I gave this a try and I got this error:

error: Syntax error
  ┌─ /Users/louis/Desktop/thing/src/thing.gleam:4:5
  │
4 │   ===
  │     ^ I can't figure out what to do with this character

Hint: Is it a typo?

This doesn't seem any clearer to me than the previous error. Let's have one like Giacomo suggested in the issue, that'll help the programmer understand what the problem is.

I also tested with == = and I got the same error, but it should have the original error and the new error should only be for ===

Thank you for the suggestions, made changes as requested please check 👍🏽

[giacomocavalieri]

I'd personally define a specific InvalidTripleEqual error variant instead of a general InvalidOperator one since we don't currently have any uses for it besides the triple equal case

[rabingaire]

Thank you for the review updated the commit 👍🏽

[giacomocavalieri]

No, thank you!

[lpil]

Thank you! Very nice. Could you update the changelog file too?

[rabingaire]

Thank you! Very nice. Could you update the changelog file too?

Thank you, added the changelog 👍🏽

[lpil]

Wonderful! Thank you