10.3.4 subint

The integer type is available in Dezyne in a restricted way¹⁴: only a finite contiguous subrange of integer numbers can be used. An explicit type definition is needed for each subset, where a C-like syntax is used.

subint  ::= "subint" identifier "{" range "}" ";"
range   ::= integer ".." integer
integer ::= ("-")? [0-9]+

An example:

subint int {-1..2};

where subint is a keyword. This defines the finite type int with possible values -1, 0, 1, and 2. Available integer operators are:

comparison

i1

i1 <= i2

i1 >= i2

i1 > i2

i1 == i2

i1 != i2

i1 + i2,

Integer addition,

i1 - i2

Integer subtraction,

where i1 and i2 denote integers.

note: Integers of different subint types can be used in comparison, assignment, and function calls. The verifier will check that the resulting integer value is within the defined subint range.