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ps_map

container.ps_map

§
(PK 
type
, V 
type
)
:
Map PK, V
 is
 
[Private constructor]

ps_map -- a partially sorted map

ps_map is a persistent map from an ordered key PK to a value V. This map is
generally well-behaved with respect to cumulative and average performance.

The keys and values are stored in arrays consisting of sorted sub-arrays,
with sub-arrays corresponding to the 1-bits in the binary representation
of the size.

This results in cumulative memory usage in O(size log² size), worst-case
lookup time in O(log² size) and average addition time in O(1) and worst-case
addition time in O(size log² size).

WARNING: Due to the high worst-case time for addition, this structure should
not be used in situations when adding a single element repeatedly to the same
instance of ps_map is performance critical. If the resulting map's size n is a
power of 2, this will trigger the worst-case addition time resulting in
O(m*n log² n) for adding an element m times.

This constructor is for internal use only, to create instance of ps_map, use
ps_map PK V without arguments.

Type Parameters

§
PK
:
Any 
[Private constructor]
key type
§
V
:
Any 
[Private constructor]
value type

Fields

§
size
 i32  
[Redefinition of  container.Map.size]
the number of key and value pairs in this map.

redefines:

Functions

add mapping from kv.values.0 to kv.values.1

Adding has a cumulative average runtime in O(log size) and a worst-case
runtime of O(size)
§
(k container.ps_map.PK, v container.ps_map.V)
 => 
container.this.ps_map container.ps_map.PK container.ps_map.V
add mapping from k to v
create sorted array of all keys in this map
§
 => 
String  
[Inherited from  Map]
create a string containing all mappings

redefines:

§
 => 
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.
§
(k container.Map.K)
 => 
bool  
[Inherited from  Map]
check if key k is present in the set of keys
§
(k container.ps_map.PK)
 => 
option container.ps_map.V  
[Redefinition of  container.Map.index [ ]]
find the value k is mapped to or nil if k is not part of this map
infix operator synonym for union of two ps_maps
get an array of all key/value pairs in this map
§
 => 
Sequence container.Map.K  
[Inherited from  Map]
get a sequence of all keys in this map
get the highest key in this map
get the lowest key in this map
§
 => 
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.
union of two ps_maps

creates a new ps_map that maps all the keys that exist either in ps_map.this
or in other to the values they are mapped to. In case a key k exists in
both ps_map.this and other, it will be mapped to ps_map.this[k] or to other[k],
but it is undefined to which of these two.
§
 => 
Sequence container.Map.V  
[Inherited from  Map]
get a sequence of all values in this map

Type Functions

§
 => 
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:

§
 => 
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:

empty -- an empty partially sorted map

This feature creates an empty instance of ps_map.
§
(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

§
 => 
String  
[Inherited from  Type]
name of this type, including type parameters, e.g. 'option (list i32)'.
ps_map -- routine to initialize a partially sorted map from two Sequences

This feature creates a pre-initialized instance of ps_map.
§
 => 
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:

§
 => 
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`.