Gerbil Scheme

Hash Tables

make-hash-table

(make-hash-table . options) -> hash table

options:
    size: size
    init: init
    weak-keys: weak-keys?
    weak-values: weak-values?
    test: test
    hash: hash
    min-load: min-load
    max-load: max-load

Creates a hash table.

make-hash-table-eq

(make-hash-table-eq . options) -> hash table

Creates a hash table using eq? as the test function so this is equivalent to (make-hash-table test: eq? options ...).

make-hash-table-eqv

(make-hash-table-eqv . options) -> hash table

Creates a hash table using eqv? as the test function so this is equivalent to (make-hash-table test: eqv? options ...).

hash?

(hash? obj) -> boolean

  obj := any object

Returns true if the object is a hash table.

hash-table?

(hash-table? obj) -> boolean

  obj := any object

Same as hash?.

hash-length

(hash-length hash) -> fixnum

  hash := hash table

Returns the number of entries in the hash.

hash-ref

(hash-ref hash key [default]) -> any

  hash := hash table
  key  := any

Returns the value bound to key, defaulting to default if no value was bound. If the default is absent, then if an init parameter was specified in the table constructor it is returned instead. If no init parameter was specified, then an error is raised.

hash-get

(hash-get hash key) -> any

  hash := hash table
  key  := any

Returns the value bound to key or #f if no value was bound. This is equivalent to (hash-ref hash key #f).

hash-put!

(hash-put! hash key val) -> void

  hash := hash table
  key  := any
  val  := val

Binds key to val in hash.

hash-update!

(hash-update! hash key update [default = #!void]) -> void

  hash := hash table
  key  := any
  update: = procedure of one argument

Updates hash's binding for key to the result of (update (hash-ref hash key default))

hash-remove!

(hash-remove! hash key) -> void

  hash := hash table
  key  := any

Removes hash's binding for key.

hash-clear!

(hash-clear! hash [size = 0]) -> void

  hash := hash table
  size := fixnum; the new initial size for the hash table or 0 for default

Clears the hash table.

hash-key?

(hash-key? hash key) -> boolean

  hash := hash table
  key  := any

Returns true if hash has a binding for key.

hash-for-each

(hash-for-each proc hash) -> void

  proc := procedure of two arguments
  hash := hash table

Applies proc to all key/value bindings in hash.

hash-map

(hash-map proc hash) -> list

  proc := procedure of two arguments
  hash := hash table

Maps the bindings of hash to a list, applying proc.

hash-fold

(hash-fold proc iv hash) -> any

  proc := procedure of three arguments
  iv   := any; initial value
  hash := hash table

Fold the bindings of hash, applying proc with initial iv.

hash-find

(hash-find proc hash) -> any

  proc := procedure of two arguments
  hash := hash table

Returns the first true value returned when applying proc to the bindings of hash or #f.

hash-keys

(hash-keys hash) -> list

  hash := hash table

Returns the list of keys for all bindings in hash.

hash-values

(hash-values hash) -> list

  hash := hash table

Returns the list of values for all bindings in hash.

hash-copy

(hash-copy hash) -> hash table

  hash := hash table

Copies hash into a new hash table

hash-merge

(hash-merge hash . more) -> hash table

  hash := hash table
  more := list of hash tables

Creates a new hash table, merging more hash tables into hash. Entries in hash tables on the left take precedence over entries on the right.

> (define t1 (list->hash-table '((a . 1) (b . 2) (c . 3))))
> (define t2 (list->hash-table '((a . 4) (b . 5) (z . 6))))
> (hash->list (hash-merge t1 t2))
((a . 1) (z . 6) (b . 2) (c . 3))

hash-merge!

(hash-merge! hash . more) -> hash table

  hash := hash table
  more := list of hash tables

:::

Merges more hash tables into hash. Entries in hash tables on the left take precedence over entries on the right.

> (define t1 (list->hash-table '((a . 1) (b . 2) (c . 3))))
> (define t2 (list->hash-table '((a . 4) (b . 5) (z . 6))))
> (begin (hash-merge! t1 t2) (hash->list t1))
((a . 1) (z . 6) (b . 2) (c . 3))

hash->list

(hash->list hash) -> list

  hash := hash table

Returns the bindings of hash as an alist.

list->hash-table

(list->hash-table lst . options) -> hash table

  lst := alist; table bindings

Creates a hash table from an alist lst.

list->hash-table-eq

(list->hash-table-eq lst . options) -> hash table

  lst := alist; table bindings

Same as list->hash-table, but using eq? as the test function for the table.

list->hash-table-eqv

(list->hash-table-eqv lst . options) -> hash table

  lst := alist; table bindings

Same as list->hash-table, but using eqv? as the test function for the table.

hash->plist

(hash->plist hash) -> list

  hash := hash table

Returns the bindings of hash as a plist.

plist->hash-table

(plist->hash-table lst) -> hash table

  lst := plist; table bindings

Creates a hash table from a plist lst.

plist->hash-table-eq

(plist->hash-table-eq lst) -> hash table

  lst := plist; table bindings

Same as plist->hash-table, but using eq? as the test function for the table.

plist->hash-table-eqv

(plist->hash-table-eqv lst) -> hash table

  lst := plist; table bindings

Same as plist->hash-table, but using eqv? as the test function for the table.

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