Shorthand numeric updates
Color 64 allows a numeric variable or numeric array element to be updated without repeating the variable name on the right side of the assignment.
For example: A+12 is equivalent to: A=A+12
Subtraction is also supported: A-12 is equivalent to: A=A-12
When no expression follows the operator, Color 64 assumes a value of one: A+ is equivalent to: A=A+1
A- is equivalent to: A=A-1
The value following the operator may be any valid numeric BASIC expression. For example:
- A+X*2
- A-(B+C)
- HM+
- N%(I)-1
Both floating-point and integer variables are supported, including array elements. String variables are not supported by this shorthand syntax.
Only the addition (+) and subtraction (-) operators should be used. Other arithmetic or logical operators are not supported in this form.
Note: Shorthand updates to integer variables use direct 16-bit arithmetic. If the result exceeds the integer range of -32768 through 32767, the value may wrap around rather than generate an overflow error.