☰
tuple
tuple
Functions
create a String from this instance. Unless redefined, `a.as_string` will
create `"instance[T]"` where `T` is the dynamic type of `a`
create `"instance[T]"` where `T` is the dynamic type of `a`
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.
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.
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.
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 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
result has the form "Type of '<name>'", but this might change in the future
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.
endless hierarchy of types, so dynamic_type is redefined to just return
Type.type here.
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
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
name of this type, including type parameters, e.g. 'option (list i32)'.
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`.
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`.
tuple types provide algebraic product types of all the generic arguments
provided to tuple.
The values within a tuple 'tuple A B C' can be accessed via the tuple's
argument field 'values' followed by a selector referring to the generic
argument's position: 'values.0', 'values.1' and 'values.2', respectively.
Syntactic sugar of the Fuzion language permits an alternative notation
to create values of tuple types as follows
t := (a, b, c, ... )
is equivalent to
t := tuple a b c ...
The actual generic types are inferred from the static types of the values
'a', 'b', 'c', ... the tuple is created from.
Similarly, syntactic sugar for the destructuring of tuples can be used
to access the values as in
(a, b, c, ...) := t
In destructurings, we can denote values we are not interested in using
'_' as in
(_, b) := ("first", "second")
which will set 'b' to '"second"' and drop the first element of the tuple.
As an example, say we want to identify a person by its name and its age,
so we can define
a := ("Alice" , 11)
b := ("Bob" , 22)
c := ("Claire", 33)
Then, we could extract Bob's age using
(_, age) := b
or Claire's name using
(name, _) := c
Destructuring also works for general features, e.g.
point (x,y i32) is {}
p := point 3, 4
(px, py) := p # will set px to 3 and py to 4
and the destructured value can then be used to create a tuple
t := (px, py) # will create tuple<i32,i32> instance
however, tuples are not assignment compatible with general features even
if they would destructure into the same types, i.e.,
u tuple i32 i32 = p # will cause compile time error
q point = (7, 12) # will cause compile time error
The unit tuple '()' can be used as a short-hand to create the empty tuple
'tuple'. The empty tuple can be destructured like any other tuple
using
() := ()
even though this has no effect.
An instance of the single tuple 'tuple A' with sole element 'a' can not
be created using syntactic sugar '(a)', this will produce the plain
value of 'a' instead. However, destructuring of a single tuple is possible:
(a0) := tuple a
which is equivalent to
a0 := a
NYI: A single tuple 'tuple A' is currently not assignment compatible with
type 'A', which would make handling of general tuples easier.
tuples and destructuring can be used to swap two elements or create a
permutation as in
(a, b) := (b, a)
(o, t, a, n) := (n, a, t, o)
A tuple type with no actual generic arguments is isomorphic to 'unit', i.e, it
is a type that has only one single value: '()'.