Enumap

A structure that maps each member of an enum to a single value.

An Enumap is a lightweight alternative to an associative array that is useable when your key type is an enum.

It provides some added benefits over the AA, such as array-wise operations, default values for all keys, and some nice opDispatch based syntactic sugar for element access.

The key enum must be backed by an integral type and have 'default' numbering. The backing value must start at 0 and grows by 1 for each member.

struct Enumap (

) if (

EnumMembers!K == aliasSeqOf!(EnumMembers!K.length.iota)

) {

static immutable

auto length;

this(V[length] values);

this(R values);

void opAssign(T val);

auto ref opIndex(K key);

auto ref opDispatch();

int opApply(int delegate(K, const V) dg);

int opApply(int delegate(K, ref V) dg);

auto opBinary(typeof(this) other);

auto opOpAssign(typeof(this) other);

}

Constructors

this this(V[length] values): Construct an Enumap from a static array.
this this(R values): Assign from a range with a number of elements exactly matching length.

Members

Functions

byKey auto byKey(): Get a range iterating over the members of the enum K.
byKeyValue auto byKeyValue(): Return a range of (EnumMember, value) pairs.
byValue auto byValue(): Get a range iterating over the stored values.
opApply int opApply(int delegate(K, const V) dg): Execute a foreach statement over (EnumMember, value) pairs.
opApply int opApply(int delegate(K, ref V) dg): Execute foreach over (EnumMember, ref value) pairs to modify elements.
opAssign void opAssign(T val): An Enumap can be assigned from an array or range of values
opBinary auto opBinary(typeof(this) other): Apply an array-wise operation between two Enumaps.
opDispatch auto ref opDispatch(): Access the value at the index specified by the name of an enum member.
opIndex auto ref opIndex(K key): Access the value at the index specified by an enum member.
opOpAssign auto opOpAssign(typeof(this) other): Perform an in-place operation.
opUnary auto opUnary(): Perform a unary operation on each entry.

Static variables

length auto length;: The number of entries in the Enumap

Parameters

K: The type of enum used as a key. The enum values must start at 0, and increase by 1 for each entry.
V: The type of value stored for each enum member