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I'm teaching an introductory programming class, using Scala. We are starting with the REPL. The REPL has a bug in that, when the student enters a readLine command, their input is not echoed. Is there some workaround that I can suggest or provide?
I don't have this trouble when using Eclipse, but it will be some weeks before I introduce Eclipse to my students.
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println ( "Hello" ) // Console is imported by default, so it's not really needed, just use println println ( "World" ) // readLine lets you prompt the user and read their input as a String val name = readLine ( "What's your name? " ) // readInt lets you read an Int, but you have to prompt the user manually print ( "How ...
The Scala REPL (“Read-Evaluate-Print-Loop”) is a command-line interpreter that you use as a “playground” area to test your Scala code. To start a REPL session, just type scala at your operating system command line, and you'll see this: $ scala Welcome to Scala 2.13.0 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_131).
You can use power mode to get access to the REPL's reader; it will give you a fully working readLine:
scala> :power
** Power User mode enabled - BEEP WHIR GYVE **
** :phase has been set to 'typer'. **
** scala.tools.nsc._ has been imported **
** global._, definitions._ also imported **
** Try :help, :vals, power.<tab> **
scala> repl.in.readLine("enter something: ")
enter something: hello world
res0: String = hello world
scala>
Edit: as @som-snytt pointed out, in 2.11 you can use reader instead of repl.in in the above code, which is both shorter and easier to remember.
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