Fuzion Logo
fuzion-lang.dev — The Fuzion Language Portal
»

Unary

Unary

(T 
type
, U 
type
)
 ref
:
Function T, U
 is
[Contains abstract features]
Unary -- function that takes exactly one argument and returns a result

T is the result type of the function, U is the argument type of the function

For unary functions, function composition is possible if the result type of
the first function matches the argument type of the second function.

Type Parameters

Functions

 => 
String
[Inherited from  Any]
[Contains abstract features]
create a String from this instance. Unless redefined, `a.as_string` will
create `"instance[T]"` where `T` is the dynamic type of `a`
(a Function.A...)
 => 
Function.R
[Inherited from  Function]
[Abstract feature]
[Contains abstract features]
call this function on given arguments a...
(V 
type
, other Unary Unary.U V)
 => 
Unary Unary.T V
[Contains abstract features]
function composition
 => 
Type
[Inherited from  Any]
[Contains abstract features]
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.
(V 
type
, other Unary Unary.U V)
 => 
Unary Unary.T V
[Contains abstract features]
function composition (Unicode alias)
 => 
String
[Inherited from  Any]
[Contains abstract features]
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.

Type Functions

 => 
String
[Inherited from  Type]
[Contains abstract features]
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:

 => 
Type
[Inherited from  Type]
[Contains abstract features]
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:

(T 
type
)
 => 
bool
[Inherited from  Type]
[Contains abstract features]
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
same
pre T : property.equatable
=>
a = b

or

val(n T) is

# check if T is numeric, if so
# return true if n > zero,
# return nil if T is not numeric
#
more_than_zero option bool =>
if T : numeric then
n > T.zero
else
nil
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
 => 
String
[Inherited from  Type]
[Contains abstract features]
name of this type, including type parameters, e.g. 'option (list i32)'.
 => 
String
[Inherited from  Type]
[Contains abstract features]
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:

 => 
Type
[Inherited from  Any]
[Contains abstract features]
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`.
0.094dev (2025-06-18 15:08:51 GIT hash 89cffc23ae669b0898a5564fefbf793fcb8e5ca7 built by fridi@fzen)