# Map¶

Usage

use Map;


or

import Map;


This module contains the implementation of the map type which is a container that stores key-value associations.

Maps are not parallel safe by default, but can be made parallel safe by setting the param formal parSafe to true in any map constructor. When constructed from another map, the new map will inherit the parallel safety mode of its originating map.

record map
type keyType

Type of map keys.

type valType

Type of map values.

param parSafe = false

If true, this map will perform parallel safe operations.

proc init(type keyType, type valType, param parSafe = false)

Initializes an empty map containing keys and values of given types.

Arguments
• keyType – The type of the keys of this map.

• valType – The type of the values of this map.

• parSafe – If true, this map will use parallel safe operations.

proc init(type keyType, type valType, param parSafe = false)
proc init=(other: map(?kt, ?vt, ?ps))

Initializes a map containing elements that are copy initialized from the elements contained in another map.

Arguments
• other : map – The map to initialize from.

• parSafe : bool – If true, this map will use parallel safe operations.

proc clear()

Clears the contents of this map.

Warning

Clearing the contents of this map will invalidate all existing references to the elements contained in this map.

proc size

The current number of keys contained in this map.

proc isEmpty(): bool

Returns true if this map contains zero keys.

Returns

true if this map is empty.

Return type

bool

proc contains(const k: keyType): bool

Returns true if the given key is a member of this map, and false otherwise.

Arguments

k : keyType – The key to test for membership.

Returns

Whether or not the given key is a member of this map.

Return type

bool

proc extend(m: map(keyType, valType, parSafe))

Extends this map with the contents of the other, overwriting the values for already-existing keys.

Arguments

m : map(keyType, valType) – The other map

proc update(m: map(keyType, valType, parSafe))

Updates this map with the contents of the other, overwriting the values for already-existing keys.

Warning

Adding to a map using update is deprecated. Please use the extend method instead.

Arguments

m : map(keyType, valType) – The other map

proc update(const ref k: keyType, updater) throws

Update a value in this map in a parallel safe manner via an updater object.

The updater object passed to the update() method must define a this() method that takes two arguments: the first has this map’s keyType, and the second has this map’s valType.

The updater object’s this() method must return some sort of value. Updater objects that do not need to return anything may return none.

If the updater object’s this() method throws, the thrown error will be propagated out of update().

Arguments
• k : keyType – The key to update

• updater – A class or record used to update the value at i

Returns

What the updater returns

proc ref this(k: keyType) ref

Get the value mapped to the given key, or add the mapping if key does not exist.

Arguments

k : keyType – The key to access

Returns

Reference to the value mapped to the given key.

proc getBorrowed(k: keyType)

Get a borrowed reference to the element at position k.

proc getReference(k: keyType) ref

Get a reference to the element at position k. This method is not available for maps initialized with parSafe=true.

proc getValue(k: keyType)

Get a copy of the element stored at position k.

proc getAndRemove(k: keyType)

Remove the element at position k from the map and return its value

iter these() const ref

Iterates over the keys of this map. This is a shortcut for keys.

Yields

A reference to one of the keys contained in this map.

iter keys() const ref

Iterates over the keys of this map.

Yields

A reference to one of the keys contained in this map.

iter items()

Iterates over the key-value pairs of this map.

Yields

A tuple whose elements are a copy of one of the key-value pairs contained in this map.

iter values() ref

Iterates over the values of this map.

Yields

A reference to one of the values contained in this map.

proc readWriteThis(ch: channel) throws

Writes the contents of this map to a channel. The format looks like:

{k1: v1, k2: v2, .... , kn: vn}

Arguments

ch – A channel to write to.

proc add(in k: keyType, in v: valType): bool

Adds a key-value pair to the map. Method returns false if the key already exists in the map.

Arguments
• k : keyType – The key to add to the map

• v : valueType – The value that maps to k

Returns

true if k was not in the map and added with value v. false otherwise.

Return type

bool

proc set(k: keyType, in v: valType): bool

Sets the value associated with a key. Method returns false if the key does not exist in the map.

Arguments
• k : valueType – The key whose value needs to change

• v – The desired value to the key k

Returns

true if k was in the map and its value is updated with v. false otherwise.

Return type

bool

proc addOrSet(in k: keyType, in v: valType)

If the map doesn’t contain a value at position k add one and set it to v. If the map already contains a value at position k, update it to the value v.

proc remove(k: keyType): bool

Removes a key-value pair from the map, with the given key.

Arguments

k – The key to remove from the map

Returns

false if k was not in the map. true if it was and removed.

Return type

bool

proc toArray(): [] (keyType, valType)

Returns a new 0-based array containing a copy of key-value pairs as tuples.

Returns

A new DefaultRectangular array.

Return type

[] (keyType, valType)

proc keysToArray(): [] keyType

Returns a new 0-based array containing a copy of keys. Array is not guaranteed to be in any particular order.

Returns

A new DefaultRectangular array.

Return type

[] keyType

proc valuesToArray(): [] valType

Returns a new 0-based array containing a copy of values. Array is not guaranteed to be in any particular order.

Returns

A new DefaultRectangular array.

Return type

[] valType

proc type map.=(ref lhs: map(?kt, ?vt, ?), const ref rhs: map(kt, vt, ?))

Replace the content of this map with the other’s.

Warning

This will invalidate any references to elements previously contained in lhs.

Arguments
• lhs – The map to assign to.

• rhs – The map to assign from.

proc type map.==(const ref a: map(?kt, ?vt, ?ps), const ref b: map(kt, vt, ps)): bool

Returns true if the contents of two maps are the same.

Arguments
• a : map – A map to compare.

• b : map (with same keyType and valType) – A map to compare.

Returns

true if the contents of two maps are equal.

Return type

bool

proc type map.!=(const ref a: map(?kt, ?vt, ?ps), const ref b: map(kt, vt, ps)): bool

Returns true if the contents of two maps are not the same.

Arguments
• a : map – A map to compare.

• b : map (with same keyType and valType) – A map to compare.

Returns

true if the contents of two maps are not equal.

Return type

bool

proc type map.+(a: map(?keyType, ?valueType, ?), b: map(keyType, valueType, ?))

Returns a new map containing the keys and values in either a or b.

proc type map.+=(ref a: map(?keyType, ?valueType, ?), b: map(keyType, valueType, ?))

Sets the left-hand side map to contain the keys and values in either a or b.

proc type map.|(a: map(?keyType, ?valueType, ?), b: map(keyType, valueType, ?))

Returns a new map containing the keys and values in either a or b.

proc type map.|=(ref a: map(?keyType, ?valueType, ?), b: map(keyType, valueType, ?))

Sets the left-hand side map to contain the keys and values in either a or b.

proc type map.&(a: map(?keyType, ?valueType, ?), b: map(keyType, valueType, ?))

Returns a new map containing the keys that are in both a and b.

proc type map.&=(ref a: map(?keyType, ?valueType, ?), b: map(keyType, valueType, ?))

Sets the left-hand side map to contain the keys that are in both a and b.

proc type map.-(a: map(?keyType, ?valueType, ?), b: map(keyType, valueType, ?))

Returns a new map containing the keys that are only in a, but not b.

proc type map.-=(ref a: map(?keyType, ?valueType, ?), b: map(keyType, valueType, ?))

Sets the left-hand side map to contain the keys that are in the left-hand map, but not the right-hand map.

proc type map.^(a: map(?keyType, ?valueType, ?), b: map(keyType, valueType, ?))

Returns a new map containing the keys that are in either a or b, but not both.

proc type map.^=(ref a: map(?keyType, ?valueType, ?), b: map(keyType, valueType, ?))

Sets the left-hand side map to contain the keys that are in either the left-hand map or the right-hand map, but not both.