void
void
Functions
apply -- apply `f.call` to the value stored in this choice
This can be used to perform operation on values of arbitray choice types.
Example:
which prints
This can be used to perform operation on values of arbitray choice types.
Example:
which prints
create a string from this choice.
This will use the value stored stored in this choice and create its String
representation using `prefix $` and return that without any additional
information.
This will use the value stored stored in this choice and create its String
representation using `prefix $` and return that without any additional
information.
create a detailed string from this choice.
This will createa string of the form `type.tag(T,v)` consisting of
the string representations of
So, e.g., `(id (option String) "hi").as_string` will result in
`"option String.0(String,hi)"`
This will createa string of the form `type.tag(T,v)` consisting of
the string representations of
So, e.g., `(id (option String) "hi").as_string` will result in
`"option String.0(String,hi)"`
combine -- if `choice.this` and `other` have the same ordinal number, combine
the value stored in this `ta` and in other `ov` using `f.call va vb`.
Otherwise, return `e`.
This can be used to combine values of arbitrary choice types.
the value stored in this `ta` and in other `ov` using `f.call va vb`.
Otherwise, return `e`.
This can be used to combine values of arbitrary choice types.
dynamic_apply -- apply `f.call` to `Any.this`'s dynamic type and value
This can be used to perform operation on values depending on their dynamic
type.
Here is an example that takes a `Sequence Any` that may contain boxed values
of types `i32` and `f64`. We can now write a feature `get_f64` that extracts
these values converted to `f64` and build a function `sum` that sums them up
as follows:
This can be used to perform operation on values depending on their dynamic
type.
Here is an example that takes a `Sequence Any` that may contain boxed values
of types `i32` and `f64`. We can now write a feature `get_f64` that extracts
these values converted to `f64` and build a function `sum` that sums them up
as follows:
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.
Ordinal number corresponding to the index in this choice's open type
parameters of the type of the value stored in this choice.
Note that this is defined even for choices of ambiguous types like
`option nil`: Even though this type may only contain `nil` it can
still be distinguished:
is `0` while
is `1`.
parameters of the type of the value stored in this choice.
Note that this is defined even for choices of ambiguous types like
`option nil`: Even though this type may only contain `nil` it can
still be distinguished:
is `0` while
is `1`.
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 "<name>", but this might change in the future
result has the form "<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.
Note: Typechecking is undecidable when 'type' is a type, Mark B. Reinhold, 1989
see: https://dspace.mit.edu/bitstream/handle/1721.1/149366/MIT-LCS-TR-458.pdf?sequence=6
endless hierarchy of types, so dynamic_type is redefined to just return
Type.type here.
Note: Typechecking is undecidable when 'type' is a type, Mark B. Reinhold, 1989
see: https://dspace.mit.edu/bitstream/handle/1721.1/149366/MIT-LCS-TR-458.pdf?sequence=6
equality of two choices `a` and `b` is defined only if all element types
of the choice are equatable. The choices are equal if they have the same
ordinal number and the contained values are equal.
This will result in a compile time panic in case any element type is not
equatable.
of the choice are equatable. The choices are equal if they have the same
ordinal number and the contained values are equal.
This will result in a compile time panic in case any element type is not
equatable.
create hash code for this instance
This should satisfy the following condition:
(T.equality a b) : (T.hash_code a = T.hash_code b)
This should satisfy the following condition:
(T.equality a b) : (T.hash_code a = T.hash_code b)
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.
it is most useful in conjunction with preconditions or `if` statements as in
or
The result of this is a compile-time constant that can be used to specialize
code for a particular type.
it is most useful in conjunction with preconditions or `if` statements as in
or
A total order between two choices `a` and `b` is defined only if all element types
of the choice are orderable.
their first elements. If the first `i` element pairs are equal, the order is defined by
the `i+1`th element pair.
This will result in a compile time panic in case any element type is not
orderable.
of the choice are orderable.
their first elements. If the first `i` element pairs are equal, the order is defined by
the `i+1`th element pair.
This will result in a compile time panic in case any element type is not
orderable.
name of this type, including type parameters, e.g. 'option (list i32)'.
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
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
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`.
Applicable universe features
These are features in universe, that have an argument with a type constraint that matches this features type and can therefore be used with it.
equals -- feature that compares two values using the equality relation
defined in their type
defined in their type
hash of a value
infix = -- infix operation as shorthand for 'equals'
does this come strictly before other?
infix <= -- infix operation as shorthand for 'lteq'
three-way comparison between this and other.
result is < 0 if this < other
result is > 0 if this > other
result is = 0 if this = other
result is < 0 if this < other
result is > 0 if this > other
result is = 0 if this = other
infix = -- infix operation as shorthand for 'equals'
does this come strictly after other?
does this come after other?
is `a` contained in `Set` `s`?
This should usually be called using type inference as in
This should usually be called using type inference as in
is `a` not contained in `Set` `s`?
This should usually be called using type inference as in
This should usually be called using type inference as in
infix ≤ -- infix operation as shorthand for 'lteq'
does this come after other?
three-way comparison between this and other.
result is < 0 if this < other
result is > 0 if this > other
result is = 0 if this = other
result is < 0 if this < other
result is > 0 if this > other
result is = 0 if this = other
lteq -- feature that compares two values using the lteq relation
defined in their type
defined in their type
maximum of two values
memoize `f`.
wraps f so that f will only be called once for every unique input.
The term "memoization" was coined by Donald Michie in 1968 and
is derived from the Latin word "memorandum" ("to be remembered"),
usually truncated as "memo" in American English, and thus carries
the meaning of "turning a function into something to be remembered".
https://en.wikipedia.org/wiki/Memoization
example:
wraps f so that f will only be called once for every unique input.
The term "memoization" was coined by Donald Michie in 1968 and
is derived from the Latin word "memorandum" ("to be remembered"),
usually truncated as "memo" in American English, and thus carries
the meaning of "turning a function into something to be remembered".
https://en.wikipedia.org/wiki/Memoization
example:
minimum of two values
0.099dev (GIT hash a68bce9af280552faedee34cd5433dc10b6454de)
NOTE: For a counterpart to void in C, Java, etc., see unit.fz
void is the bottom type in Fuzion, the default empty type that is a subtype of all
other types.
It is impossible to create any values of this type, consequently, it is impossible
to assign anything to a field of void type.
If used as the type of an argument field for a feature, the feature can never be
called since no value assignable to that argument could ever be produced. This
produces an absurd feature.
If used as the result type of a routine, the routine can never return.
void is the result type of the endless loop
If used as the result type of a field, the field can never be assigned a value,
since no such value can be produced, and the field can never be read since it
remains not initialized forever.
Type void is assignable to all other types, e.g, we can assign void to a value
of type i32:
Since no value of type void can ever be produced, the assignment is dead code that
will be removed by the fuzion implementation.
Type void may be used as an actual type parameter for a type parameter. If this
is done, it will turn all features that have arguments of that type into absurd
features. Also, this will ensure that any feature that produces a result of that
type to never return a result (typically to not be callable in the first place as
well). An example could be a stack of capacity zero: stack void 0 with an
absurd
and a pop function with a precondition that is always false
The memory required to store a value of void type is not defined since these
values do not exist. The Fuzion code generators typically will not generate
any code for features receiving arguments of void type or for code following
a feature call that returns void.