From 3af85ba0197a7e06ece68d66eecc546d906dba95 Mon Sep 17 00:00:00 2001
From: Peter Gyorok <Peter.Gyorok@morganstanley.com>
Date: Mon, 27 Jun 2022 17:21:14 +0100
Subject: [PATCH] escape some characters in string display

---
 src/main/studio/kdb/K.java     | 29 ++++++++++++++++++++++++-----
 src/test/studio/kdb/KTest.java |  6 ++++++
 2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/src/main/studio/kdb/K.java b/src/main/studio/kdb/K.java
index fefebdec..ae453ae7 100755
--- a/src/main/studio/kdb/K.java
+++ b/src/main/studio/kdb/K.java
@@ -851,7 +851,7 @@ public boolean isNull() {
         public StringBuilder format(StringBuilder builder, KFormatContext context) {
             builder = super.format(builder, context);
             if (context.showType()) {
-                builder.append("\"").append(c).append("\"");
+                builder.append("\"").append(escape(c)).append("\"");
             } else {
                 builder.append(c);
             }
@@ -875,6 +875,19 @@ public boolean equals(Object obj) {
             }
             return c == ((KCharacter) obj).c;
         }
+
+        public static String escape(char ch) {
+            switch(ch) {
+                case '\000':
+                    return "\\000";
+                case '\"':
+                    return "\\\"";
+                case '\\':
+                    return "\\\\";
+                default:
+                    return String.valueOf(ch);
+            }
+        }
     }
 
     public static class KFloat extends KBase implements ToDouble {
@@ -1924,6 +1937,8 @@ public String getDataType() {
 
         public KCharacterVector(String value) {
             super(value.toCharArray(), 10, "char", "c");
+            System.out.println("value="+value+" length="+value.length());
+            new Exception().printStackTrace();
         }
 
         public KCharacter at(int i) {
@@ -1938,17 +1953,21 @@ public String getString() {
         protected StringBuilder formatVector(StringBuilder builder, KFormatContext context) {
             if (getLength() == 1) {
                 char ch = Array.getChar(array, 0);
-                if (ch <= 255) {
+                if (ch <= 127) {    //for UTF-8, any char with code of 128 or above is encoded in multiple bytes
                     builder.append(enlist);
                 }
             }
 
             if (context.showType()) {
                 builder.append("\"");
-            }
-            builder.append(getString());
-            if (context.showType()) {
+                String str = getString();
+                for (int i=0; i<str.length(); ++i) {
+                    char ch = str.charAt(i);
+                    builder.append(KCharacter.escape(ch));
+                }
                 builder.append("\"");
+            } else {
+                builder.append(getString());
             }
             return builder;
         }
diff --git a/src/test/studio/kdb/KTest.java b/src/test/studio/kdb/KTest.java
index bf180d92..6039fce0 100644
--- a/src/test/studio/kdb/KTest.java
+++ b/src/test/studio/kdb/KTest.java
@@ -138,10 +138,16 @@ public void testBooleanToString() throws Exception {
     public void testCharacterToString() throws Exception {
         check(new K.KCharacter(' '), " ", "\" \"");
         check(new K.KCharacter('a'), "a", "\"a\"");
+        check(new K.KCharacter('\000'), "\000", "\"\\000\"");
+        check(new K.KCharacter('\\'), "\\", "\"\\\\\"");
+        check(new K.KCharacter('"'), "\"", "\"\\\"\"");
 
         check(new K.KCharacterVector(" a"), " a", "\" a\"");
         check(new K.KCharacterVector(""), "", "\"\"");
         check(new K.KCharacterVector("a"), "enlist a", "enlist \"a\"");
+        check(new K.KCharacterVector(" \000"), " \000", "\" \\000\"");
+        check(new K.KCharacterVector(" \\"), " \\", "\" \\\\\"");
+        check(new K.KCharacterVector(" \""), " \"", "\" \\\"\"");
     }
 
     @Test