Is there an eval() function in Java? [duplicate]

Answer 1

With Java 9, we get access to jshell, so one can write something like this:

import jdk.jshell.JShell;
import java.lang.StringBuilder;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

public class Eval {
    public static void main(String[] args) throws IOException {
        try(JShell js = JShell.create(); BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {

            js.onSnippetEvent(snip -> {
                if (snip.status() == jdk.jshell.Snippet.Status.VALID) {
                    System.out.println("➜ " + snip.value());
                }
            });

            System.out.print("> ");
            for (String line = br.readLine(); line != null; line = br.readLine()) {
                js.eval(js.sourceCodeAnalysis().analyzeCompletion(line).source());
                System.out.print("> ");
            }
        }
    }
}

Sample run:

> 1 + 2 / 4 * 3
➜ 1
> 32 * 121
➜ 3872
> 4 * 5
➜ 20
> 121 * 51
➜ 6171
>

Slightly op, but that's what Java currently has to offer