Add LPAREN, RPAREN, COMMA token types to the scanner

Extends the vec0 tokenizer to recognize '(', ')', and ',' as
single-character tokens, preparing for DiskANN index option parsing.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

sqlite-vec.c

@@ -1814,6 +1814,9 @@ enum Vec0TokenType {
   TOKEN_TYPE_RBRACKET,
   TOKEN_TYPE_PLUS,
   TOKEN_TYPE_EQ,
+  TOKEN_TYPE_LPAREN,
+  TOKEN_TYPE_RPAREN,
+  TOKEN_TYPE_COMMA,
 };
 struct Vec0Token {
   enum Vec0TokenType token_type;
@@ -1864,6 +1867,24 @@ int vec0_token_next(char *start, char *end, struct Vec0Token *out) {
       out->end = ptr;
       out->token_type = TOKEN_TYPE_EQ;
       return VEC0_TOKEN_RESULT_SOME;
+    } else if (curr == '(') {
+      ptr++;
+      out->start = ptr;
+      out->end = ptr;
+      out->token_type = TOKEN_TYPE_LPAREN;
+      return VEC0_TOKEN_RESULT_SOME;
+    } else if (curr == ')') {
+      ptr++;
+      out->start = ptr;
+      out->end = ptr;
+      out->token_type = TOKEN_TYPE_RPAREN;
+      return VEC0_TOKEN_RESULT_SOME;
+    } else if (curr == ',') {
+      ptr++;
+      out->start = ptr;
+      out->end = ptr;
+      out->token_type = TOKEN_TYPE_COMMA;
+      return VEC0_TOKEN_RESULT_SOME;
     } else if (is_alpha(curr)) {
       char *start = ptr;
       while (ptr < end && (is_alpha(*ptr) || is_digit(*ptr) || *ptr == '_')) {

tests/sqlite-vec-internal.h

@@ -23,6 +23,9 @@ enum Vec0TokenType {
   TOKEN_TYPE_RBRACKET = 3,
   TOKEN_TYPE_PLUS = 4,
   TOKEN_TYPE_EQ = 5,
+  TOKEN_TYPE_LPAREN = 6,
+  TOKEN_TYPE_RPAREN = 7,
+  TOKEN_TYPE_COMMA = 8,
 };
 
 #define VEC0_TOKEN_RESULT_EOF   1

tests/test-unit.c

@@ -108,6 +108,24 @@ void test_vec0_token_next() {
   assert(token.token_type == TOKEN_TYPE_DIGIT);
   assert(token.end - token.start == 2);
 
+  // Left paren
+  input = "(";
+  rc = vec0_token_next(input, input + 1, &token);
+  assert(rc == VEC0_TOKEN_RESULT_SOME);
+  assert(token.token_type == TOKEN_TYPE_LPAREN);
+
+  // Right paren
+  input = ")";
+  rc = vec0_token_next(input, input + 1, &token);
+  assert(rc == VEC0_TOKEN_RESULT_SOME);
+  assert(token.token_type == TOKEN_TYPE_RPAREN);
+
+  // Comma
+  input = ",";
+  rc = vec0_token_next(input, input + 1, &token);
+  assert(rc == VEC0_TOKEN_RESULT_SOME);
+  assert(token.token_type == TOKEN_TYPE_COMMA);
+
   printf("  All vec0_token_next tests passed.\n");
 }
 
@@ -229,6 +247,60 @@ void test_vec0_scanner() {
     assert(rc == VEC0_TOKEN_RESULT_EOF);
   }
 
+  // Scan "diskann(k=v, k2=v2)"
+  {
+    const char *input = "diskann(k=v, k2=v2)";
+    vec0_scanner_init(&scanner, input, (int)strlen(input));
+
+    rc = vec0_scanner_next(&scanner, &token);
+    assert(rc == VEC0_TOKEN_RESULT_SOME);
+    assert(token.token_type == TOKEN_TYPE_IDENTIFIER);
+    assert(strncmp(token.start, "diskann", 7) == 0);
+
+    rc = vec0_scanner_next(&scanner, &token);
+    assert(rc == VEC0_TOKEN_RESULT_SOME);
+    assert(token.token_type == TOKEN_TYPE_LPAREN);
+
+    rc = vec0_scanner_next(&scanner, &token);
+    assert(rc == VEC0_TOKEN_RESULT_SOME);
+    assert(token.token_type == TOKEN_TYPE_IDENTIFIER);
+    assert(strncmp(token.start, "k", 1) == 0);
+
+    rc = vec0_scanner_next(&scanner, &token);
+    assert(rc == VEC0_TOKEN_RESULT_SOME);
+    assert(token.token_type == TOKEN_TYPE_EQ);
+
+    rc = vec0_scanner_next(&scanner, &token);
+    assert(rc == VEC0_TOKEN_RESULT_SOME);
+    assert(token.token_type == TOKEN_TYPE_IDENTIFIER);
+    assert(strncmp(token.start, "v", 1) == 0);
+
+    rc = vec0_scanner_next(&scanner, &token);
+    assert(rc == VEC0_TOKEN_RESULT_SOME);
+    assert(token.token_type == TOKEN_TYPE_COMMA);
+
+    rc = vec0_scanner_next(&scanner, &token);
+    assert(rc == VEC0_TOKEN_RESULT_SOME);
+    assert(token.token_type == TOKEN_TYPE_IDENTIFIER);
+    assert(strncmp(token.start, "k2", 2) == 0);
+
+    rc = vec0_scanner_next(&scanner, &token);
+    assert(rc == VEC0_TOKEN_RESULT_SOME);
+    assert(token.token_type == TOKEN_TYPE_EQ);
+
+    rc = vec0_scanner_next(&scanner, &token);
+    assert(rc == VEC0_TOKEN_RESULT_SOME);
+    assert(token.token_type == TOKEN_TYPE_IDENTIFIER);
+    assert(strncmp(token.start, "v2", 2) == 0);
+
+    rc = vec0_scanner_next(&scanner, &token);
+    assert(rc == VEC0_TOKEN_RESULT_SOME);
+    assert(token.token_type == TOKEN_TYPE_RPAREN);
+
+    rc = vec0_scanner_next(&scanner, &token);
+    assert(rc == VEC0_TOKEN_RESULT_EOF);
+  }
+
   printf("  All vec0_scanner tests passed.\n");
 }