Возможность изменить вывод в консоли или перенаправить вывод в строку

src/main/java/com/annimon/ownlang/Console.java

@@ -1,6 +1,8 @@
 package com.annimon.ownlang;
 
 import com.annimon.ownlang.lib.CallStack;
+import com.annimon.ownlang.outputsettings.ConsoleOutputSettings;
+import com.annimon.ownlang.outputsettings.OutputSettings;
 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.PrintStream;
@@ -10,43 +12,50 @@ public class Console {
 
     private Console() { }
     
-    private static final String FILE_PREFIX = "tmp/";
-    private static boolean filePrefixEnabled;
+    private static OutputSettings outputSettings = new ConsoleOutputSettings();
 
-    public static void enableFilePrefix() {
-        Console.filePrefixEnabled = true;
+    public static void useSettings(OutputSettings outputSettings) {
+        Console.outputSettings = outputSettings;
+    }
+
+    public static OutputSettings getSettings() {
+        return outputSettings;
     }
 
     public static String newline() {
-        return System.lineSeparator();
+        return outputSettings.newline();
     }
 
     public static void print(String value) {
-        System.out.print(value);
+        outputSettings.print(value);
     }
 
     public static void print(Object value) {
-        print(value.toString());
+        outputSettings.print(value);
     }
 
     public static void println() {
-        System.out.println();
+        outputSettings.println();
     }
 
     public static void println(String value) {
-        System.out.println(value);
+        outputSettings.println(value);
     }
 
     public static void println(Object value) {
-        println(value.toString());
+        outputSettings.println(value);
+    }
+
+    public static String text() {
+        return outputSettings.getText();
     }
 
     public static void error(Throwable throwable) {
-        error(throwable.toString());
+        outputSettings.error(throwable);
     }
 
     public static void error(CharSequence value) {
-        System.err.println(value);
+        outputSettings.error(value);
     }
 
     public static void handleException(Thread thread, Throwable throwable) {
@@ -68,14 +77,6 @@ public class Console {
     }
 
     public static File fileInstance(String path) {
-        final String filepath;
-        if (filePrefixEnabled) {
-            filepath = FILE_PREFIX.concat(path);
-        } else {
-            filepath = path;
+        return outputSettings.fileInstance(path);
     }
-        return new File(filepath);
-    }
-
-
 }

src/main/java/com/annimon/ownlang/outputsettings/ConsoleOutputSettings.java

@@ -0,0 +1,56 @@
+package com.annimon.ownlang.outputsettings;
+
+import java.io.File;
+
+public class ConsoleOutputSettings implements OutputSettings {
+
+    @Override
+    public String newline() {
+        return System.lineSeparator();
+    }
+
+    @Override
+    public void print(String value) {
+        System.out.print(value);
+    }
+
+    @Override
+    public void print(Object value) {
+        print(value.toString());
+    }
+
+    @Override
+    public void println() {
+        System.out.println();
+    }
+
+    @Override
+    public void println(String value) {
+        System.out.println(value);
+    }
+
+    @Override
+    public void println(Object value) {
+        println(value.toString());
+    }
+
+    @Override
+    public String getText() {
+        return "";
+    }
+
+    @Override
+    public void error(Throwable throwable) {
+        error(throwable.toString());
+    }
+
+    @Override
+    public void error(CharSequence value) {
+        System.err.println(value);
+    }
+
+    @Override
+    public File fileInstance(String path) {
+        return new File(path);
+    }
+}

src/main/java/com/annimon/ownlang/outputsettings/OutputSettings.java

@@ -0,0 +1,27 @@
+package com.annimon.ownlang.outputsettings;
+
+import java.io.File;
+
+public interface OutputSettings {
+
+    String newline();
+
+    void print(String value);
+
+    void print(Object value);
+
+    void println();
+
+    void println(String value);
+
+    void println(Object value);
+
+    String getText();
+
+    void error(Throwable throwable);
+
+    void error(CharSequence value);
+
+    File fileInstance(String path);
+
+}

src/main/java/com/annimon/ownlang/outputsettings/StringOutputSettings.java

@@ -0,0 +1,71 @@
+package com.annimon.ownlang.outputsettings;
+
+import java.io.File;
+
+public class StringOutputSettings implements OutputSettings {
+
+    private final StringBuffer out, err;
+
+    public StringOutputSettings() {
+        this(new StringBuffer());
+    }
+
+    public StringOutputSettings(StringBuffer out) {
+        this(out, out);
+    }
+
+    public StringOutputSettings(StringBuffer out, StringBuffer err) {
+        this.out = out;
+        this.err = err;
+    }
+
+    @Override
+    public String newline() {
+        return System.lineSeparator();
+    }
+
+    @Override
+    public void print(String value) {
+        out.append(value);
+    }
+
+    @Override
+    public void print(Object value) {
+        out.append(value.toString());
+    }
+
+    @Override
+    public void println() {
+        out.append(newline());
+    }
+
+    @Override
+    public void println(String value) {
+        out.append(value).append(newline());
+    }
+
+    @Override
+    public void println(Object value) {
+        println(value.toString());
+    }
+
+    @Override
+    public String getText() {
+        return out.toString();
+    }
+
+    @Override
+    public void error(Throwable throwable) {
+        error(throwable.toString());
+    }
+
+    @Override
+    public void error(CharSequence value) {
+        err.append(value).append(newline());
+    }
+
+    @Override
+    public File fileInstance(String path) {
+        return new File(path);
+    }
+}

src/main/java/com/annimon/ownlang/utils/Sandbox.java

@@ -3,12 +3,14 @@ package com.annimon.ownlang.utils;
 import com.annimon.ownlang.Console;
 import com.annimon.ownlang.exceptions.StoppedException;
 import com.annimon.ownlang.lib.CallStack;
+import com.annimon.ownlang.outputsettings.ConsoleOutputSettings;
 import com.annimon.ownlang.parser.Lexer;
 import com.annimon.ownlang.parser.Parser;
 import com.annimon.ownlang.parser.SourceLoader;
 import com.annimon.ownlang.parser.Token;
 import com.annimon.ownlang.parser.ast.Statement;
 import com.annimon.ownlang.parser.visitors.FunctionAdder;
+import java.io.File;
 import java.io.IOException;
 import java.text.SimpleDateFormat;
 import java.util.Arrays;
@@ -18,7 +20,12 @@ import java.util.List;
 public final class Sandbox {
 
     public static void main(String[] args) throws IOException {
-        Console.enableFilePrefix();
+        Console.useSettings(new ConsoleOutputSettings() {
+            @Override
+            public File fileInstance(String path) {
+                return new File("tmp/" + path);
+            }
+        });
         final String input = SourceLoader.readAndCloseStream(System.in);
         dumpInputArguments(input, args);
         

src/test/java/com/annimon/ownlang/parser/ProgramsTest.java

@@ -1,8 +1,11 @@
 package com.annimon.ownlang.parser;
 
+import com.annimon.ownlang.Console;
 import com.annimon.ownlang.lib.Functions;
 import com.annimon.ownlang.lib.NumberValue;
 import com.annimon.ownlang.lib.Variables;
+import com.annimon.ownlang.outputsettings.OutputSettings;
+import com.annimon.ownlang.outputsettings.StringOutputSettings;
 import com.annimon.ownlang.parser.ast.FunctionDefineStatement;
 import com.annimon.ownlang.parser.ast.Statement;
 import com.annimon.ownlang.parser.ast.Visitor;
@@ -94,6 +97,22 @@ public class ProgramsTest {
         }
     }
 
+    @Test
+    public void testOutput() throws IOException {
+        OutputSettings oldSettings = Console.getSettings();
+        Console.useSettings(new StringOutputSettings());
+        String source = "for i = 0, i <= 5, i++\n  print i";
+        final Statement s = Parser.parse(Lexer.tokenize(source));
+        try {
+            s.execute();
+            assertEquals("012345", Console.text());
+        } catch (Exception oae) {
+            Assert.fail(oae.toString());
+        } finally {
+            Console.useSettings(oldSettings);
+        }
+    }
+
     private static Visitor testFunctionsExecutor = new AbstractVisitor() {
         @Override
         public void visit(FunctionDefineStatement s) {