Token separation

Hi,

I just tried to input a hexadecimal number in PostgreSQL
(8.4) and was rather surprised by the result:

| tim=# SELECT 0x13;
|  x13
| -----
|    0
| (1 Zeile)

| tim=# SELECT 0abc;
|  abc
| -----
|    0
| (1 Zeile)

| tim=#

The documentation says:

| A token can be a key word, an identifier, a quoted identifi-
| er, a literal (or constant), or a special character symbol.
| Tokens are normally separated by whitespace (space, tab,
| newline), but need not be if there is no ambiguity (which is
| generally only the case if a special character is adjacent
| to some other token type).

Is this behaviour really conforming to the standard?  Even
stranger is what MySQL (5.1.59) makes out of it:

| mysql> SELECT 0x40;
| +------+
| | 0x40 |
| +------+
| | @    |
| +------+
| 1 row in set (0.00 sec)

| mysql> SELECT 0abc;
| ERROR 1054 (42S22): Unknown column '0abc' in 'field list'
| mysql>

Tim