Viewing the contents in <function1> from the scala repl

Question

I can create anonymous functions in the scala repl like so:

scala> val a = (x: Int) => x * x
a: Int => Int = <function1>

But is there anyway of seeing what is inside after it has been created?

I'm thinking about situations where I would take a function and return a function. I'm just curious to see what the repl created as the return, rather than just the type of the returned value, so something like:

scala> val b = (f: (Int => Boolean)) => (x: Int) => ! (f(x))
b: (Int => Boolean) => (Int => Boolean) = <function1>

scala> val c = b((x: Int) => x % 2 == 0)
c: Int => Boolean = <function1>

I want to see what code has been generated inside c!

Answer 1

It's not as handy as same functionality in, say, clojure, since it shows compiled code but you can either get advantage of :javap:

scala> :javap -help
usage       :javap [opts] [path or class or -]...
-help       Prints this help message
-raw        Don't unmangle REPL names
-app        Show the DelayedInit body of Apps
-fun        Show anonfuns for class or Class#method
-verbose/-v Stack size, number of locals, method args
-private/-p Private classes and members
-package    Package-private classes and members
-protected  Protected classes and members
-public     Public classes and members
-l          Line and local variable tables
-c          Disassembled code
-s          Internal type signatures
-sysinfo    System info of class
-constants  Static final constants

scala> :javap -s a
Compiled from "<console>"
public class  {
  public static final  MODULE$;
    descriptor: L;
  public static {};
    descriptor: ()V

  public scala.Function1<java.lang.Object, java.lang.Object> a();
    descriptor: ()Lscala/Function1;

  public ();
    descriptor: ()V
}

Or instruct REPL to output code internals on compilation with scala -Xprint:typer (though it might be overly verbose, maybe someone can suggest less wordy compiler stage to use).

BTW, as you can see in :javap output, every REPL expression is implicitly wrapped with surrounding code, don't be confused -- scala does not perform it normally.