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Is there a way to evaluate a arbitrary string from Scala as if the same text was entered into the Scala REPL directly? I mean, I would like to do something like this:
scala> eval("val x = 42")
scala> x
res2: Int = 42
Since the Scala REPL is accepting commands in an eval loop using jline (I believe) and then compiling/interpreting it, there has to be a way to submit an arbitrary line of text. I am willing to hack the Scala REPL if necessary.
372
The REPL reads expressions at the prompt In interactive mode, then wraps them into an executable template, and after that compiles and executes the result. Either an object Or a class can be wrapped by user code the switch used is -Yrepl-class-based. Each and every line of input is compiled separately.
The Scala REPL is a tool (scala) for evaluating expressions in Scala. The scala command will execute a source script by wrapping it in a template and then compiling and executing the resulting program.
The Scala REPL (“Read-Evaluate-Print-Loop”) is a command-line interpreter that you use as a “playground” area to test your Scala code.
res in scala shell are val. you can verify this by trying to reassign a value to res. e.g. - scala> List(1)
No REPL hacking necessary—just switch to power user mode, which gives you access to the current scala.tools.nsc.interpreter.IMain as intp:
scala> :power
** Power User mode enabled - BEEP BOOP SPIZ **
** :phase has been set to 'typer'. **
** scala.tools.nsc._ has been imported **
** global._ and definitions._ also imported **
** Try :help, vals.<tab>, power.<tab> **
scala> intp.interpret("val x = 42")
x: Int = 42
res0: scala.tools.nsc.interpreter.package.IR.Result = Success
scala> x
res1: Int = 42
This works since at least 2.9.1.
137
Another opportunity is to use Eval from Twitter Utility:
val x: Int = new Eval()("1 + 1")
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