Eberon Associative Arrays

Associative arrays are indexed by string keys. The basic operations on a such array is storing a value (having declared type) and extracting the value given the key (string).

Syntax

Associative arrays are declared using keyword MAP:

VAR m: MAP OF INTEGER; (* m is associative array storing integer values *)

TYPE T = RECORD field: MAP OF T END; (* associative array can have records as values *)

Semantics

Notation similar to ordinary arrays is used to acceess, add a new element or replace existing element (with the same key) in associative array:

m[key] := value; (* add/replace element *)
value := m[key]; (* get element *)

key type should be compatible with STRING and value should be compatible with declared type. Attempt to access element with non-existing key will break program execution.

Keyword IN is used to test whether element with specified key is present in the array:

IF key IN m THEN

It is also possible to iterate through associative array keys/values using FOR..IN loop.

To remove element from array remove method is used:

m.remove(key)

To remove all elements from array clear method is used:

m.clear()