SWI-Prolog -- Manual

Documentation
- Reference manual
  - Overview
    - The SWI-Prolog syntax
      - ISO Syntax Support
        
        Processor Character Set
        
        Nested comments
        
        Character Escape Syntax
        
        Syntax for non-decimal numbers
        
        Using digit groups in large integers
        
        Rational number syntax
        
        NaN and Infinity floats and their syntax
        
        Force only underscore to introduce a variable
        
        Unicode Prolog source
        
        Singleton variable checking
- Packages

2.16.1.4 Syntax for non-decimal numbers

SWI-Prolog implements both Edinburgh and ISO representations for non-decimal numbers. According to Edinburgh syntax, such numbers are written as <radix>’<number>, where <radix> is a number between 2 and 36. ISO defines binary, octal and hexadecimal numbers using 0[bxo]<number>. For example: A is 0b100 \/ 0xf00 is a valid expression. Such numbers are always unsigned.