Hi! I'm starting to use arrow for data validation ...

# arrow

[Dorian Codes]

Hi! I'm starting to use arrow for data validation (I'm not super familiar with the library, but I used cats/scalaz libraries for scala in the past). Following the docs about Validated I noticed that this snippet doesn't compile

data class Config(val map: Map<String, String>) {
  suspend fun <A> parse(read: Read<A>, key: String) = either<ConfigError, A> {
    val value = Validated.fromNullable(map[key]) {
      ConfigError.MissingConfig(key)
    }.bind()
    val readVal = Validated.fromNullable(read.read(value)) {
      ConfigError.ParseConfig(key)
    }.bind()
    readVal
  }

In particular I wasn't able to call bind() from a Validated. Is that something I am missing? Also I noticed that bind() is not listed among the functions for Validated in the docs. I'm using arrow-core version 0.11.0

[Cody Mikol]

This compiles fine for me, what error are you receiving?

[Cody Mikol]

bind is part of the EitherEffect interface, it’s part of the this context inside the either { } lambda

[Dorian Codes]

Thanks for the help. Here for example (sorry for the bad formatting):

val value = Validated.fromNullable(map[key]) {
ConfigError.MissingConfig(key)
}.bind()

The IDE is complaining that it can't find the function "bind()". But If I write


val value = Validated.fromNullable(map[key]) {
ConfigError.MissingConfig(key)
}
.toEither()
.bind()

It compiles. Even if this val are declared locally inside the lambda

Validated
.fromNullable(map[key]){
ConfigError.MissingConfig(key)
}

is of type Validated, not Either. Hence my confusion...