nested-hash🔗 i

Kevin R. Stravers

(require nested-hash ) package: nested-hash

Provides hash-ref and hash-set variants that operate on nested hash tables, that is, a hash table inside a hash table.

procedure
( nested-hash-ref hash*
key...+
[ #:defaultdefault]) → any?
hash*:hash?
key:any/c
default:any/c =#f

Accesses a hash table recursively using the given keys. default is returned if a key does not exist. An error is raised if an access is performed on a non-hash entry.

procedure
( nested-hash-set hash*
key...+
value
[ #:hashhash]) → any?
hash*:hash?
key:any/c
value:any/c
hash:any/c =hash

Functionally edits a hash table using the given keys and value. Non-existent keys will automatically become new subtables. Existing intermediate keys that are associated with non-hash values will raise an error. The #:hash keyword specifies a constructor for creating new nested hash tables.

Examples:

> (nested-hash-ref (hash 'a(hash 'b123))'a'b)

123
> (nested-hash-set (hash )'a'b123)

'#hash((a. #hash((b. 123))))

Similarly to the previous functions we have similar functions that take actual lists instead of inline-lists. These may be useful to avoid using apply when generating lists of accesses.

procedure
( nested-hash-ref* hash*
keys
[ #:defaultdefault]) → any?
hash*:hash?
keys:(listof any/c )
default:any/c =#f

Accesses a hash table recursively using the given keys. default is returned if a key does not exist. An error is raised if an access is performed on a non-hash entry.

procedure
( nested-hash-set* hash*
keys
value
[ #:hashhash]) → any?
hash*:hash?
keys:(listof any/c )
value:any/c
hash:any/c =hash

Examples:

> (nested-hash-ref* (hash 'a(hash 'b123))'(ab))

123
> (nested-hash-set* (hash )'(ab)123)

'#hash((a. #hash((b. 123))))

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