Add multiline input to REPL

Fix bug where REPL input is echoed back
Fix bug where an exclamation point would cause a JLine event exception
Input can now be continued on the next line with a '\' character at the end of the line. The character will be disregarded as whitespace in the parser.

Resolves #13

3 files changed, 42 insertions, 12 deletions

diff --git a/src/main/com/jantuomi/tunkki/core/parser/ASTGenerator.java b/src/main/com/jantuomi/tunkki/core/parser/ASTGenerator.java
index 29f5ba2..41ea0ec 100644
--- a/src/main/com/jantuomi/tunkki/core/parser/ASTGenerator.java
+++ b/src/main/com/jantuomi/tunkki/core/parser/ASTGenerator.java
@@ -29,13 +29,18 @@ public class ASTGenerator {
         return list;
     }
 
-    public void printTree(ASTNode root) {
+    public void printTree(ASTNode root) throws TunkkiError {
         System.out.println("### AST Tree begin ###");
-        root.print(0);
+        try {
+            root.print(0);
+        } catch (NullPointerException ex) {
+            throw new TunkkiError(TunkkiError.ExceptionType.GeneralError, -1, "Malformed syntax tree.");
+        }
+
         System.out.println("### AST Tree end ###");
     }
 
-    public void printAllTrees(List<ASTNode> trees) {
+    public void printAllTrees(List<ASTNode> trees) throws TunkkiError {
         for (ASTNode tree : trees) {
             printTree(tree);
         }
diff --git a/src/main/com/jantuomi/tunkki/core/runtime/Interpreter.java b/src/main/com/jantuomi/tunkki/core/runtime/Interpreter.java
index 5674dab..0c986c3 100644
--- a/src/main/com/jantuomi/tunkki/core/runtime/Interpreter.java
+++ b/src/main/com/jantuomi/tunkki/core/runtime/Interpreter.java
@@ -21,8 +21,14 @@ public class Interpreter {
     }
     public static String execute(List<ASTNode> sequence) throws TunkkiError {
         String output = "";
+        Datatype data;
         for (ASTNode node : sequence) {
-            Datatype data = node.evaluate();
+            try {
+                 data = node.evaluate();
+            }
+            catch (NullPointerException ex) {
+                throw new TunkkiError(TunkkiError.ExceptionType.GeneralError, -1, "Malformed input.");
+            }
 
             if (data != null) {
                 output = data.toString();
diff --git a/src/main/com/jantuomi/tunkki/repl/Repl.java b/src/main/com/jantuomi/tunkki/repl/Repl.java
index 817d746..3b63b6e 100644
--- a/src/main/com/jantuomi/tunkki/repl/Repl.java
+++ b/src/main/com/jantuomi/tunkki/repl/Repl.java
@@ -1,6 +1,7 @@
 package com.jantuomi.tunkki.repl;
 
 import com.jantuomi.tunkki.Tunkki;
+import com.jantuomi.tunkki.core.parser.datatype.IntegerDatatype;
 import com.jantuomi.tunkki.exception.TunkkiError;
 import jline.console.*;
 
@@ -23,17 +24,33 @@ public class Repl {
 
         ConsoleReader reader = new ConsoleReader();
         reader.setBellEnabled(false);
+        reader.setExpandEvents(false);
 
         String line;
+        String command = "";
         PrintWriter out = new PrintWriter(System.out);
-
-        while ((line = readLine(reader, "")) != null) {
-            try {
-                tunkki.run(line);
+        boolean isMultilineInput = false;
+        while (true)  {
+            if (isMultilineInput) {
+                line = readLine(reader, "... ");
+            } else {
+                line = readLine(reader, "tunkki> ");
             }
-            catch (TunkkiError ex) {
-                ex.printStackTrace();
-                Thread.sleep(50);
+
+            if (line.endsWith("\\")) {
+                isMultilineInput = true;
+                command += line.substring(0, line.length() - 1) + " ";
+            } else {
+                try {
+                    isMultilineInput = false;
+                    command += line;
+                    tunkki.run(command);
+                } catch (TunkkiError ex) {
+                    ex.printStackTrace();
+                    Thread.sleep(50);
+                } finally {
+                    command = "";
+                }
             }
 
             out.flush();
@@ -42,11 +59,13 @@ public class Repl {
 
     private String readLine(ConsoleReader reader, String promptMessage)
             throws IOException {
-        String line = reader.readLine(promptMessage + "\ntunkki> ");
+        System.out.print(promptMessage);
+        String line = reader.readLine();
         return line.trim();
     }
 
     private void showWelcomeText() {
         System.out.println(String.format("tunkki REPL version %s", tunkki.versionString()));
+        System.out.println("Copyright: Jan Tuomi 2016");
     }
 }