Feature Request: Support Automatic Conversion of snake_case to camelCase

[linkedlist771]

Configuration (required)

version = 3.7.3  // Latest scalafmt version as of May 21, 2024

Command-line parameters (required)

When I run scalafmt via CLI like this:

scalafmt --test 

it does not automatically convert snake_case to camelCase.

Steps

Given code like this:

val data_in = 42
def process_data(input_value: Int) = input_value * 2

Problem

Scalafmt does not modify the naming convention and leaves the code unchanged:

val data_in = 42
def process_data(input_value: Int) = input_value * 2

Expectation

I would like the formatted output to look like this:

val dataIn = 42
def processData(inputValue: Int) = inputValue * 2

Workaround

Currently, there is no automated workaround within scalafmt. Manual correction or custom scripts are the only options.

Notes

• This feature would align scalafmt with the widely accepted camelCase convention in Scala.
• A similar feature request has been discussed for other languages, suggesting a broader need.
• While exploring solutions in the OpenXiangShan project, a custom Python script was developed, highlighting the lack of existing tooling for this conversion.
• This feature origins from this PR.

[kitbellew]

scalafmt cannot do what you want. it's a syntactic tool, and you need a semantic tool instead, such as scalafix.

you should resubmit this in scalafix and, in the meantime, add a scalastyle rule such as a ClassNamesChecker to validate camels, snakes or kebabs, as needed.

P.S. The comment below was true a year ago.

version = 3.7.3  // Latest scalafmt version as of May 21, 2024