Print methods of the Console effect should not depend on Abort[IOException]

[rcardin]

Fixes #1037

Problem

The Scala Console.println doesn't throw an IOException. The method uses the Java PrintStream type, which fails silently in case of errors. So, the kyo.Console effect should not depend upon an Abort[IOException] for printing text on the console.

We should rewrite the code such that the examples in the documentation will change accordingly:

val b: Unit < IO = Console.print("ok")

// Print to stdout with a new line
val c: Unit < IO = Console.printLine("ok")

// Print to stderr
val d: Unit < IO = Console.printErr("fail")

// Print to stderr with a new line
val e: Unit < IO = Console.printLineErr("fail")

// Explicitly specifying the 'Console' implementation
val f: Unit < IO = Console.let(Console.live)(e)

See PrintWriter and PrintStream never throw IOExceptions for further details.

Solution

I removed the Abort[IOException] effect from the return type of the kyo.Console methods concerning printing. Moreover, I added the following method, which returns whether the output or the error stream behind the scala.Console encountered an IOException error:

def checkErrors(using Frame): Boolean < IO

[fwbrasil]

Can you also update the top Console scaladoc with the rationale for not having a pending abort + the role of checkErrors? I think it's important to clearly flag this behavior to the user.

[rcardin]

Done. Let me know if the text works for you.

[fwbrasil]

perfect! thanks