Dict (data type)

Dicts

Dicts are one the the complex data types supported by nyan. They are also known as associative arrays or maps in other programming languages. A dict behaves like a list with the speciality that every inserted value is mapped to a key. Any non-abstract Nyan::Object can be used as a key. Referencing a key will return the associated value. Dicts can store an unlimited number of key-value pairs.

Dicts are currently not implemented in nyan.

Syntax

dict_name : dict(keyType, valueType) = {Key1: value1, Key2: value2, ..}

The contents of a dict are surrounded by curly brackets ({}). A key and its associated value are separated by a colon (:). Each key-value pair is seperated by a comma (,).

Per definition all keys must use the same type of Nyan::Object (inherited objects included). You can't use the same key twice. Values also have to be of the same type as other values, but unlike in sets there is no restriction on how often a value can occur.

Example

Unit():
    cost : dict(Resource, int)

Archer(Unit):
    cost = {Wood: 20, Gold: 45}

The dict cost has two entries: Wood: 20 and Gold: 45. The first entry uses the key Wood which has the associated value 20. The second entry's key is Gold which has the mapped value of 45. This dict can store key-value pairs where the key has the type Resource and the value is of the type Integer.

Operators

(Re-)Assignment '='

Unit():
    cost : dict(Resource, int)

Archer(Unit):
    cost = {Wood: 20, Gold: 45}

Overwrites the old value with a new one.

Addition '+='

Archer(Unit):
    cost = {Wood: 20, Gold: 45}

MoreCost<Archer>():
    cost += {Wood: 5}

Adds the given value to the value with the same key.

Substraction '-='

Archer(Unit):
    cost = {Wood: 20, Gold: 45}

MoreCost<Archer>():
    cost -= {Wood: 5}

Substracts the given value from the value with the same key.

Multiplication '*='

Archer(Unit):
    cost = {Wood: 20, Gold: 45}

MoreCost<Archer>():
    cost *= {Wood: 5}

Multiplies the given value with the value with the same key.

Division '/='

Archer(Unit):
    cost = {Wood: 20, Gold: 45}

MoreCost<Archer>():
    cost /= {Wood: 5}

Divides the original value by the given value when the keys are the same.

Appending a dict '|='

Archer(Unit):
    cost = {Wood: 20, Gold: 45}

MoreCost<Archer>():
    cost |= {Food: 10}

Adds the given key-value pairs to the dict. If a key is already present in a dict, the original key-value pair is kept.

Deleting keys '?='

Archer(Unit):
    cost = {Wood: 20, Gold: 45}

MoreCost<Archer>():
    cost ?= {Wood, Food}

Removes every key-value pair where the key matches the keys in the given set.

Keep only specified keys '&='

Archer(Unit):
    cost = {Wood: 20, Gold: 45}

MoreCost<Archer>():
    cost &= {Wood}

Removes every key-value pair where the key not matches the keys in the given set.