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wrap_around

num.wrap_around

§
:
integer
 is
  
[Contains abstract features]
 
[Private constructor]

wrap_around -- abstract ancestor of wrap-around integer numbers

wrap_around is the abstract ancestor of integer numbers that have min and
max values and operations with wrap-around semantics.

Constructors

§
:
Any
 is
  
[Inherited from  numeric]
absolute value using `|a|` built from a `prefix |` and `postfix |` as an operator
alias of `a.abs`

Due to the low precedence of `|`, this works also on expressions like `|a-b|`, even
with spaces `| a-b |`, `|a - b|`, `| a-b|` or `|a-b |`.

Nesting, however, does not work, e.g, `| - |a| |`, this requires parentheses `|(- |a|)|`.

NYI: CLEANUP: Due to #3081, we need `postfix |` as the first operation, should be
`prefix |` first

Functions

§
 => 
numeric.this  
[Inherited from  numeric]
absolute value
this integer as an array of bytes (little endian)
§
 => 
String  
[Inherited from  integer]
convert this to a decimal number in a string. If negative, add "-" as
the first character.

redefines:

§
(base u32)
 => 
String  
[Inherited from  integer]
convert this to a number using the given base. If negative, add "-" as
the first character.
§
(len i32, base u32)
 => 
String  
[Inherited from  integer]
convert this to a number using the given base. If negative, add "-" as
the first character. Extend with leading "0" until the length is at
least len
§
 => 
u8  
[Inherited from  numeric]
  
[Abstract feature]
this numeric value as an u8
§
 => 
String  
[Inherited from  integer]
create binary representation
§
(len i32)
 => 
String  
[Inherited from  integer]
create binary representation with given number of digits.
§
 => 
String  
[Inherited from  integer]
create decimal representation
§
(len i32)
 => 
String  
[Inherited from  integer]
create decimal representation with given number of digits.
§
 => 
Type  
[Inherited from  Any]
Get the dynamic type of this instance. For value instances `x`, this is
equal to `type_of x`, but for `x` with a `ref` type `x.dynamic_type` gives
the actual runtime type, while `type_of x` results in the static
compile-time type.

There is no dynamic type of a type instance since this would result in an
endless hierarchy of types. So for Type values, dynamic_type is redefined
to just return Type.type.
§
 => 
bool  
[Inherited from  numeric]
does this numeric value fit into an u8? This is redefined by children
of numeric that support `as_u8`.
§
(b integer.this)
 => 
integer.this  
[Inherited from  integer]
greatest common divisor of this and b

note that this assumes zero to be divisible by any positive integer.
§
 => 
String  
[Inherited from  integer]
create hexadecimal representation
§
(len i32)
 => 
String  
[Inherited from  integer]
create hexadecimal representation with given number of digits.
§
(other numeric.this)
 => 
numeric.this  
[Inherited from  numeric]
  
[Abstract feature]
basic operations: 'infix %' (division remainder)
§
(other integer.this)
 => 
bool  
[Inherited from  integer]

redefines:

§
(other integer.this)
 => 
bool  
[Inherited from  integer]
test divisibility by other
§
(other integer.this)
 => 
integer.this  
[Inherited from  integer]
  
[Abstract feature]
bitwise operations
multiplication, with check for overflow

redefines:


redefines:

exponentiation for positive exponent

'zero ** zero' is permitted and results in 'one'.

redefines:


redefines:

exponentiation with overflow checking semantics

'zero **? zero' is permitted and results in 'one'.

redefines:

exponentiation with saturating semantics

'zero **^ zero' is permitted and results in 'one'.

redefines:

exponentiation with wrap-around semantics

'zero **° zero' is permitted and results in 'one'.

redefines:


redefines:

addition, with check for overflow

redefines:


redefines:


redefines:


redefines:

subtraction, with check for overflow

redefines:


redefines:


redefines:


redefines:

§
(other numeric.this)
 => 
numeric.this  
[Inherited from  numeric]
  
[Abstract feature]
basic operations: 'infix /' (division)
§
(other integer.this)
 => 
bool  
[Inherited from  integer]
preconditions used in 'numeric' for basic operations: true if the
operation is permitted for the given values

redefines:

create a fraction
§
(other integer.this)
 => 
integer.this  
[Inherited from  integer]
  
[Abstract feature]
§
(other integer.this)
 => 
integer.this  
[Inherited from  integer]
  
[Abstract feature]
shift operations
§
(other integer.this)
 => 
integer.this  
[Inherited from  integer]
  
[Abstract feature]
§
(other integer.this)
 => 
integer.this  
[Inherited from  integer]
  
[Abstract feature]
create a fraction via unicode fraction slash \u2044 '⁄ '
§
 => 
bool  
[Redefinition of  integer.is_bounded]
check if this type of wrap_around is bounded

wrap_arounds are assumed to be a bound set by default, so
this returns true unless redefined by an implementation

redefines:

§
 => 
bool  
[Inherited from  numeric]
§
 => 
bool  
[Inherited from  numeric]
§
 => 
String  
[Inherited from  integer]
create octal representation
§
(len i32)
 => 
String  
[Inherited from  integer]
create octal representation with given number of digits.
§
 => 
i32  
[Abstract feature]
count the number of 1 bits in the binary representation of this
integer.
§
(other num.this.wrap_around.this)
 => 
bool  
[Abstract feature]
would addition wrap_around.this + other cause an overflow or underflow?
would exponentiation 'this ** other' cause an overflow?
§
(other num.this.wrap_around.this)
 => 
bool  
[Abstract feature]
would multiplication wrap_around.this * other cause an overflow or underflow?
§
(other num.this.wrap_around.this)
 => 
bool  
[Abstract feature]
would subtraction wrap_around.this - other cause an overflow or underflow?
§
 => 
String  
[Inherited from  Any]
convenience prefix operator to create a string from a value.

This permits usage of `$` as a prefix operator in a similar way both
inside and outside of constant strings: $x and "$x" will produce the
same string.
§
 => 
numeric.this  
[Inherited from  numeric]
basic operations: 'prefix +' (identity)
§
 => 
bool  
[Inherited from  numeric]
preconditions for basic operations: true if the operation's result is
representable and defined for the given values

default implementations all return `true` such that children have to
redefine these only for partial operations such as those resulting in
an overflow or that are undefined like a division by zero for most
types.
negation, with check for overflow

redefines:

§
 => 
bool  
[Redefinition of  numeric.prefix -!]
preconditions used in 'numeric' for basic operations: true if the
operation is permitted for the given values

redefines:

overflow checking operations

redefines:

saturating operations

redefines:

neg, add, sub, mul with wrap-around semantics
bitwise NOT

redefines:

§
 => 
integer.this  
[Inherited from  integer]
bitwise NOT (Unicode alias)
§
 => 
i32  
[Inherited from  numeric]
sign function resulting in `-1`/`0`/`+1` depending on whether `numeric.this`
is less than, equal or larger than zero
§
(other num.this.wrap_around.this)
 => 
bool  
[Abstract feature]
§
(other num.this.wrap_around.this)
 => 
bool  
[Abstract feature]
§
(other num.this.wrap_around.this)
 => 
bool  
[Abstract feature]
§
 => 
bool  
[Abstract feature]
would negation -wrap_around.this cause an overflow?

Type Functions

§
 => 
num.wrap_around.this.type  
[Abstract feature]
returns the number in whose bit representation all bits are ones
§
 => 
String  
[Inherited from  Type]
string representation of this type to be used for debugging.

result has the form "Type of '<name>'", but this might change in the future

redefines:

how many bytes does this integer use?
§
 => 
Type  
[Inherited from  Type]
There is no dynamic type of a type instance since this would result in an
endless hierarchy of types, so dynamic_type is redefined to just return
Type.type here.

redefines:

§
(a numeric.this.type, b numeric.this.type)
 => 
bool  
[Inherited from  numeric]
  
[Abstract feature]
equality
§
(v u32)
 => 
numeric.this.type  
[Inherited from  numeric]
the value corresponding to v in whatever integer implementation we have,
maximum in case of overflow
§
(a property.hashable.this.type)
 => 
u64  
[Inherited from  hashable]
  
[Abstract feature]
create hash code for this instance

This should satisfy the following condition:

(T.equality a b) : (T.hash_code a = T.hash_code b)
§
(T 
type
)
 => 
bool  
[Inherited from  Type]
Is this type assignable to a type parameter with constraint `T`?

The result of this is a compile-time constant that can be used to specialize
code for a particular type.

is_of_integer_type(n T : numeric) => T : integer
say (is_of_integer_type 1234) # true
say (is_of_integer_type 3.14) # false

it is most useful in conjunction preconditions or `if` statements as in

pair(a,b T) is

=>

or

val(n T) is

§
 => 
bool  
[Inherited from  equatable]
additional restrictions on when equality is permitted,
e.g., `option T` might require `T : property.equatable`.
to implement `equality`
§
(a numeric.this.type, b numeric.this.type)
 => 
bool  
[Inherited from  numeric]
  
[Abstract feature]
total order
§
 => 
num.wrap_around.this.type  
[Abstract feature]
maximum
§
 => 
num.wrap_around.this.type  
[Abstract feature]
minimum
§
 => 
String  
[Inherited from  Type]
name of this type, including type parameters, e.g. 'option (list i32)'.
§
 => 
numeric.this.type  
[Inherited from  numeric]
  
[Abstract feature]
identity element for 'infix *'
§
 => 
String  
[Inherited from  Type]
convenience prefix operator to create a string from a value.

This permits usage of `$` as a prefix operator in a similar way both
inside and outside of constant strings: $x and "$x" will produce the
same string.

NYI: Redefinition allows the type feature to be distinguished from its normal counterpart, see #3913

redefines:

monoid of numeric with infix * operation. Will create product of all elements
it is applied to.
monoid of numeric with infix *^ operation. Will create product of all elements
it is applied to, stopping at max/min value in case of overflow.
monoid of numeric with infix + operation. Will create sum of all elements it
is applied to.
monoid of numeric with infix +^ operation. Will create sum of all elements it
is applied to, stopping at max/min value in case of overflow.
§
 => 
numeric.this.type  
[Inherited from  numeric]
the constant '10' in whatever integer implementation we have, maximum in case of overflow
§
 => 
numeric.this.type  
[Inherited from  numeric]
the constant '2' in whatever integer implementation we have, maximum in case of overflow
§
 => 
Type  
[Inherited from  Any]
Get a type as a value.

This is a feature with the effect equivalent to Fuzion's `expr.type` call tail.
It is recommended to use `expr.type` and not `expr.type_value`.

`type_value` is here to show how this can be implemented and to illustrate the
difference to `dynamic_type`.
§
 => 
numeric.this.type  
[Inherited from  numeric]
  
[Abstract feature]
identity element for 'infix +'