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6 Iteration  6.1 The LOOP Facility 6.1.2 Variable Initialization and Stepping Clauses 6.1.2.1 Iteration Control
6.1.2.1.6 The for-as-hash subclause
In the for-as-hash subclause
the for
or as construct
iterates over the elements, keys, and values of a hash-table.
In this syntax, a compound preposition is used to designate access to a
hash table.
The variable var takes on the value of each hash key
or hash value in the supplied hash-table.
The following loop keywords serve as valid prepositions within this syntax:
- being
The keyword being introduces either the Loop schema
hash-key or hash-value.
- each, the
The loop keyword each
follows the loop keyword being when hash-key or
hash-value is used. The loop keyword the is used with
hash-keys and hash-values only for ease of reading.
This agreement isn't required.
- hash-key, hash-keys
These loop keywords access each key entry of the hash table. If
the name hash-value is supplied in a using construct with one
of these Loop schemas, the iteration can optionally access the keyed
value. The order in which the keys are accessed is undefined; empty
slots in the hash table are ignored.
- hash-value, hash-values
These loop keywords access each value entry of a
hash table. If
the name hash-key is supplied in a using construct with one of
these Loop schemas, the iteration can optionally access the key that
corresponds to the value. The order in which the keys are accessed is
undefined; empty slots in the hash table are ignored.
- using
The loop keyword using introduces
the optional key or the keyed value to
be accessed. It allows access to the hash key if iteration is over
the hash values, and the hash value if
iteration is over the hash keys.
- in, of
These loop prepositions introduce hash-table.
In effect
being
{each | the}
{hash-value |
hash-values |
hash-key |
hash-keys}
{in | of}
is a compound preposition.
Iteration stops when there are no more hash keys or hash values to be
referenced in the supplied hash-table.
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