Allow pasting multiline input (#105)

## What is the goal of this PR?

Allow user to paste multiline input to console and edit as one unit.

## What are the changes implemented in this PR?

- Set continuation prompt to be empty indentation.
- Set history of multiline query as one single unit.
- Fix #99

Author: lriuui0x0

command/ReplCommand.java

@@ -117,7 +117,8 @@ public static String getHelpMenu() {
     public static ReplCommand getCommand(LineReader reader, Printer printer, String prompt) throws InterruptedException {
         ReplCommand command = null;
         while (command == null) {
-            String[] tokens = Utils.getTokens(reader, prompt);
+            String line = Utils.readNonEmptyLine(reader, prompt);
+            String[] tokens = Utils.splitLineByWhitespace(line);
             if (tokens.length == 1 && tokens[0].equals(Exit.token)) {
                 command = new Exit();
             } else if (tokens.length == 1 && tokens[0].equals(Help.token)) {
@@ -141,6 +142,7 @@ public static ReplCommand getCommand(LineReader reader, Printer printer, String
             } else {
                 printer.error("Unrecognised command, please check help menu");
             }
+            reader.getHistory().add(line.trim());
         }
         return command;
     }

command/TransactionReplCommand.java

@@ -24,7 +24,6 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 
 import static grakn.common.collection.Collections.pair;
@@ -108,7 +107,8 @@ public static String getHelpMenu() {
 
     public static TransactionReplCommand getCommand(LineReader reader, String prompt) throws InterruptedException {
         TransactionReplCommand command;
-        String[] tokens = Utils.getTokens(reader, prompt);
+        String line = Utils.readNonEmptyLine(reader, prompt);
+        String[] tokens = Utils.splitLineByWhitespace(line);
         if (tokens.length == 1 && tokens[0].equals(Exit.token)) {
             command = new Exit();
         } else if (tokens.length == 1 && tokens[0].equals(Help.token)) {
@@ -125,21 +125,22 @@ public static TransactionReplCommand getCommand(LineReader reader, String prompt
             String file = tokens[1];
             command = new Source(file);
         } else {
-            String firstQueryLine = String.join(" ", tokens);
-            String query = getQuery(reader, firstQueryLine, prompt.length());
+            String query = readQuery(reader, prompt, line);
             command = new Query(query);
         }
+        if (command instanceof Query) reader.getHistory().add(command.asQuery().query().trim());
+        else reader.getHistory().add(line.trim());
         return command;
     }
 
-    private static String getQuery(LineReader reader, String firstQueryLine, int indentation) {
+    private static String readQuery(LineReader reader, String prompt, String firstQueryLine) {
         List<String> queryLines = new ArrayList<>();
         queryLines.add(firstQueryLine);
         while (true) {
-            String prompt = String.join("", Collections.nCopies(indentation, " "));
+            String queryPrompt = Utils.getContinuationPrompt(prompt);
             String queryLine;
             try {
-                queryLine = reader.readLine(prompt);
+                queryLine = Utils.readLineWithoutHistory(reader, queryPrompt);
             } catch (UserInterruptException | EndOfFileException e) {
                 break;
             }

common/Utils.java

@@ -23,9 +23,11 @@
 import org.jline.reader.UserInterruptException;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 
 public class Utils {
+
     public static String buildHelpMenu(List<Pair<String, String>> menu) {
         if (menu.isEmpty()) return "\n";
         int maxHelpCommandLength = menu.stream().map(x -> x.first().length()).max(Integer::compare).get();
@@ -42,13 +44,23 @@ public static String buildHelpMenu(List<Pair<String, String>> menu) {
         return sb.toString();
     }
 
-    public static String[] getTokens(LineReader reader, String prompt) throws InterruptedException {
-        String[] words = null;
-        while (words == null) {
+    public static String readLineWithoutHistory(LineReader reader, String prompt) {
+        String continuationPrompt = getContinuationPrompt(prompt);
+        reader.variable(LineReader.SECONDARY_PROMPT_PATTERN, continuationPrompt);
+        try {
+            reader.variable(LineReader.DISABLE_HISTORY, true);
+            return reader.readLine(prompt);
+        } finally {
+            reader.variable(LineReader.DISABLE_HISTORY, false);
+        }
+    }
+
+    public static String readNonEmptyLine(LineReader reader, String prompt) throws InterruptedException {
+        String line = null;
+        while (line == null) {
             try {
-                String line = reader.readLine(prompt);
-                words = Utils.splitLineByWhitespace(line);
-                if (words.length == 0) words = null;
+                line = readLineWithoutHistory(reader, prompt);
+                if (line.trim().isEmpty()) line = null;
             } catch (UserInterruptException e) {
                 if (reader.getBuffer().toString().isEmpty()) {
                     throw new InterruptedException();
@@ -57,10 +69,14 @@ public static String[] getTokens(LineReader reader, String prompt) throws Interr
                 throw new InterruptedException();
             }
         }
-        return words;
+        return line;
+    }
+
+    public static String getContinuationPrompt(String prompt) {
+        return String.join("", Collections.nCopies(prompt.length(), " "));
     }
 
-    private static String[] splitLineByWhitespace(String line) {
+    public static String[] splitLineByWhitespace(String line) {
         return Arrays.stream(line.split("\\s+")).map(String::trim).filter(x -> !x.isEmpty()).toArray(String[]::new);
     }
 }