Constant tokens¶
A constant token means a token which has a value and its value is set hardly in the code.
Types of constant tokens:
- Number
- String
Number¶
Each number is floating point. Generally it reflects the mathematical real number.
There exist the following notations:
| Name | Regex | Example |
|---|---|---|
| Decimal (including scientific notation) | [0-9]+(\.[0-9]+)?(e[\+\-]?[0-9]+)? | 1.2e45 |
| Binary | 0b[01]+ | 0b1101 |
| Octal | 0[0-7]+ | 072 |
| Hexadecimal | 0x[0-9a-f]+ | 0xa4f |
String¶
It is a sequence of unicode characters of any length (the only limit is the
memory reserved for the application). The delimiter of the string is either
single ' or double " quote. The special characters within the string
must be escaped with the backslash \.
List of special characters:
- \t - tabulator
- \n - new line
- \\ - backslash