SOM is a minimal Smalltalk dialect which was used to teach VM construction at the Hasso Plattner Institute. It was originally built at the University of Århus (Denmark) for teaching.
Currently, SOM is maintained as a research and teaching tool and has its home at: https://som-st.github.io
Integers in SOM have arbitrary precision, which means they are not strictly word-sized or indeed have any other upper limited than the available memory.
All integers are an instance of class Integer.
In the following, we define all operations on Integer.
The addition of arbitrary-precision integers returns an arbitrary-precision integer.
For example:
3 + 4 = 7.
-4 + 3 = -1.
The addition of a Double value to an integer results in a Double value.
For example:
self expect: 3 + 4.4 toEqual: 7.4 within: 0.00000001.
self expect: -4 + 3.3 toEqual: -0.7 within: 0.00000001.
Furthermore, the following should hold for int being any integer value:
int + 1 > int.
self expect: int + 1 toBeKindOf: Integer.
And of course, we also expect the following to hold:
int + arg = (arg + int).
self expect: int + arg toBeKindOf: arg class.
Subtracting an arbitrary-precision integer from another returns an arbitrary-precision integer.
For example:
4 - 3 = 1.
-4 - 3 = -7.
Subtracting a Double from an integer results in a Double value.
For example:
self expect: 4 - 3.3 toEqual: 0.7 within: 0.00000001.
self expect: -4 - 3.5 toEqual: -7.5 within: 0.00000001.
Furthermore, the following should hold for int being any integer value:
int - 1 < int.
self expect: int - 1 toBeKindOf: Integer.
And of course, we also expect the following to hold:
(int - arg) abs = (arg - int) abs.
self expect: int - arg toBeKindOf: arg class.