Support for unicode whitespaces in Lexer

src/Common/StringUtils/StringUtils.h

@@ -131,6 +131,69 @@ inline char alternateCaseIfAlphaASCII(char c)
     return c ^ 0x20;
 }
 
+inline const char * skipWhitespacesUTF8(const char * pos, const char * end)
+{
+    /// https://en.wikipedia.org/wiki/Whitespace_character
+    /// with some adjustments.
+
+    /// Code points: 0085 00A0 180E 2000..200A 2028..2029 200B..200D 202F 205F 2060 3000 FEFF
+    /// The corresponding UTF-8 is: C285 C2A0 E1A08E E28080..E2808A E280A8..E280A9 E2808B..E2808D E280AF E2819F E281A0 E38080 EFBBBF
+
+    /// We check for these bytes directly in UTF8 for simplicity reasons.
+
+    /** C2
+      *    85
+      *    A0
+      * E1 A0 8E
+      * E2
+      *    80
+      *       80..8A
+      *       A8..A9
+      *       8B..8D
+      *       AF
+      *    81
+      *       9F
+      *       A0
+      * E3 80 80
+      * EF BB BF
+      */
+
+    while (pos < end)
+    {
+        if (isWhitespaceASCII(*pos))
+        {
+            ++pos;
+        }
+        else
+        {
+            const char8_t * upos = reinterpret_cast<const char8_t *>(pos);
+
+            if (pos + 1 < end && upos[0] == 0xC2 && (upos[1] == 0x85 || upos[1] == 0xA0))
+            {
+                pos += 2;
+            }
+            else if (pos + 2 < end
+                &&    ((upos[0] == 0xE1 && upos[1] == 0xA0 && upos[2] == 0x8E)
+                    || (upos[0] == 0xE2
+                        &&    ((upos[1] == 0x80
+                            &&    ((upos[2] >= 0x80 && upos[2] <= 0x8A)
+                                || (upos[2] >= 0xA8 && upos[2] <= 0xA9)
+                                || (upos[2] >= 0x8B && upos[2] <= 0x8D)
+                                || (upos[2] == 0xAF)))
+                            || (upos[1] == 0x81 && (upos[2] == 0x9F || upos[2] == 0xA0))))
+                    || (upos[0] == 0xE3 && upos[1] == 0x80 && upos[2] == 0x80)
+                    || (upos[0] == 0xEF && upos[1] == 0xBB && upos[2] == 0xBF)))
+            {
+                pos += 3;
+            }
+            else
+                break;
+        }
+    }
+
+    return pos;
+}
+
 inline bool equalsCaseInsensitive(char a, char b)
 {
     return a == b || (isAlphaASCII(a) && alternateCaseIfAlphaASCII(a) == b);

src/Parsers/Lexer.cpp

@@ -316,7 +316,14 @@ Token Lexer::nextTokenImpl()
                 return Token(TokenType::BareWord, token_begin, pos);
             }
             else
-                return Token(TokenType::Error, token_begin, ++pos);
+            {
+                /// We will also skip unicode whitespaces in UTF-8 to support for queries copy-pasted from MS Word and similar.
+                pos = skipWhitespacesUTF8(pos, end);
+                if (pos > token_begin)
+                    return Token(TokenType::Whitespace, token_begin, pos);
+                else
+                    return Token(TokenType::Error, token_begin, ++pos);
+            }
     }
 }