scan unicode identifier

sqllexer.go

@@ -1,5 +1,7 @@
 package sqllexer
 
+import "unicode/utf8"
+
 type TokenType int
 
 const (
@@ -98,7 +100,7 @@ func (s *Lexer) Scan() Token {
 	case isWhitespace(ch):
 		return s.scanWhitespace()
 	case isLetter(ch):
-		return s.scanIdentifier()
+		return s.scanIdentifier(ch)
 	case isDoubleQuote(ch):
 		return s.scanDoubleQuotedIdentifier('"')
 	case isSingleQuote(ch):
@@ -114,9 +116,9 @@ func (s *Lexer) Scan() Token {
 		if isDigit(nextCh) || nextCh == '.' {
 			return s.scanNumberWithLeadingSign()
 		}
-		return s.scanOperator()
+		return s.scanOperator(ch)
 	case isDigit(ch):
-		return s.scanNumber()
+		return s.scanNumber(ch)
 	case isWildcard(ch):
 		return s.scanWildcard()
 	case ch == '$':
@@ -125,21 +127,21 @@ func (s *Lexer) Scan() Token {
 			return s.scanPositionalParameter()
 		}
 		if s.config.DBMS == DBMSSQLServer && isLetter(s.lookAhead(1)) {
-			return s.scanIdentifier()
+			return s.scanIdentifier(ch)
 		}
 		return s.scanDollarQuotedString()
 	case ch == ':':
 		if s.config.DBMS == DBMSOracle && isLetter(s.lookAhead(1)) {
 			return s.scanBindParameter()
 		}
-		return s.scanOperator()
+		return s.scanOperator(ch)
 	case ch == '@':
 		if s.config.DBMS == DBMSSQLServer && isLetter(s.lookAhead(1)) {
 			return s.scanBindParameter()
 		}
-		return s.scanOperator()
+		return s.scanOperator(ch)
 	case isOperator(ch):
-		return s.scanOperator()
+		return s.scanOperator(ch)
 	case isPunctuation(ch):
 		if ch == '[' && s.config.DBMS == DBMSSQLServer {
 			return s.scanDoubleQuotedIdentifier('[')
@@ -157,7 +159,8 @@ func (s *Lexer) lookAhead(n int) rune {
 	if s.cursor+n >= len(s.src) || s.cursor+n < 0 {
 		return 0
 	}
-	return rune(s.src[s.cursor+n])
+	r, _ := utf8.DecodeRuneInString(s.src[s.cursor+n:])
+	return r
 }
 
 // peek returns the rune at the cursor position.
@@ -172,10 +175,11 @@ func (s *Lexer) nextBy(n int) rune {
 		return 0
 	}
 	s.cursor += n
-	if s.cursor == len(s.src) {
+	if s.cursor >= len(s.src) {
 		return 0
 	}
-	return rune(s.src[s.cursor])
+	r, _ := utf8.DecodeRuneInString(s.src[s.cursor:])
+	return r
 }
 
 // next advances the cursor by 1 position and returns the rune at the cursor position.
@@ -197,17 +201,17 @@ func (s *Lexer) matchAt(match []rune) bool {
 
 func (s *Lexer) scanNumberWithLeadingSign() Token {
 	s.start = s.cursor
-	s.next() // consume the leading sign
-	return s.scanNumberic()
+	ch := s.next() // consume the leading sign
+	return s.scanNumberic(ch)
 }
 
-func (s *Lexer) scanNumber() Token {
+func (s *Lexer) scanNumber(ch rune) Token {
 	s.start = s.cursor
-	return s.scanNumberic()
+	return s.scanNumberic(ch)
 }
 
-func (s *Lexer) scanNumberic() Token {
-	if s.peek() == '0' {
+func (s *Lexer) scanNumberic(ch rune) Token {
+	if ch == '0' {
 		nextCh := s.lookAhead(1)
 		if nextCh == 'x' || nextCh == 'X' {
 			return s.scanHexNumber()
@@ -288,12 +292,12 @@ func (s *Lexer) scanString() Token {
 	}
 }
 
-func (s *Lexer) scanIdentifier() Token {
+func (s *Lexer) scanIdentifier(ch rune) Token {
 	// NOTE: this func does not distinguish between SQL keywords and identifiers
 	s.start = s.cursor
-	ch := s.next()
+	ch = s.nextBy(utf8.RuneLen(ch))
 	for isLetter(ch) || isDigit(ch) || ch == '.' || ch == '?' || ch == '$' {
-		ch = s.next()
+		ch = s.nextBy(utf8.RuneLen(ch))
 	}
 	// return the token as uppercase so that we can do case insensitive matching
 	return Token{IDENT, s.src[s.start:s.cursor]}
@@ -339,9 +343,8 @@ func (s *Lexer) scanWhitespace() Token {
 	return Token{WS, s.src[s.start:s.cursor]}
 }
 
-func (s *Lexer) scanOperator() Token {
+func (s *Lexer) scanOperator(lastCh rune) Token {
 	s.start = s.cursor
-	lastCh := s.peek()
 	ch := s.next()
 	for isOperator(ch) && !(lastCh == '=' && ch == '?') {
 		// hack: we don't want to treat "=?" as an single operator

sqllexer_test.go

@@ -547,6 +547,65 @@ func TestLexer(t *testing.T) {
 	}
 }
 
+func TestLexerUnicode(t *testing.T) {
+	tests := []struct {
+		input     string
+		expected  []Token
+		lexerOpts []lexerOption
+	}{
+		{
+			input: `Descripció_CAT`,
+			expected: []Token{
+				{IDENT, `Descripció_CAT`},
+			},
+		},
+		{
+			input: `世界`,
+			expected: []Token{
+				{IDENT, `世界`},
+			},
+		},
+		{
+			input: `こんにちは`,
+			expected: []Token{
+				{IDENT, `こんにちは`},
+			},
+		},
+		{
+			input: `안녕하세요`,
+			expected: []Token{
+				{IDENT, `안녕하세요`},
+			},
+		},
+		{
+			input: `über`,
+			expected: []Token{
+				{IDENT, `über`},
+			},
+		},
+		{
+			input: `résumé`,
+			expected: []Token{
+				{IDENT, `résumé`},
+			},
+		},
+		{
+			input: `"über"`,
+			expected: []Token{
+				{IDENT, `"über"`},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run("", func(t *testing.T) {
+			lexer := New(tt.input, tt.lexerOpts...)
+			tokens := lexer.ScanAll()
+			assert.Equal(t, tt.expected, tokens)
+		})
+	}
+}
+
 func ExampleLexer() {
 	query := "SELECT * FROM users WHERE id = 1"
 	lexer := New(query)