kutils ยป Hash table utilities

Reader macro

The package has an optional reader macro that attempts to make Clojure-like hash table literals in the reader. For example:

CL-USER> (gethash :foo  #{:foo :bar :baz :quux}#)
:BAR
T
CL-USER> (let ((m #{:foo :bar :baz :quux}#))
           (sethash :baz :woz m)
           (hashkeys m))
(:BAZ :FOO)
CL-USER> (hashtable-to-alist #{:a :b :c :d}#)
((:C . :D) (:A . :B))

enable-hash-table-readernil

Enables the reader macro #{}# for hash-tables. The resulting hash-table will use #'equal for equality. For example,

#{:a :b :c :d}#

will create a hash-table with the keys :a and :c; :a stores the value :b, and :c stores the value :d.

Table manipulation

hashkeys(ht)
Returns a list of the keys in a hash table.
sethash(k v ht)
Convenience notation for setting a value in a hash table.
new-hash-tablenil
Create a new hash table with the #'equal function as its test.
hash-table-to-alist(ht)
Converts the hash-table argument to an alist of (key . value) pairs.
copy-hash-table(ht)
Shallow copy ht.

with-new-hash-table

with-new-hash-table is a convenience macro for creating a new hash table and acting on it.

In the simplest case, it takes a single symbol and a body:

* (with-new-hash-table (ht)
    (sethash "case" '("neuromancer") ht)
    (sethash "bigend" '("pattern recognition"
			"spook country"
			"zero history")
	     ht))
#<HASH-TABLE :TEST EQUAL :COUNT 2 {1009044DC3}>

If more than one symbol is provided, the resulting hash tables will be returned as an alist:

* (with-new-hash-table (neuromancer pattern-recognition)
    (sethash "places"
	     '("chiba city"
	       "istanbul"
	       "villa straylight")
	     neuromancer)
    (sethash "places"
	     '("london"
	       "tokyo"
	       "moscow")
	     pattern-recognition))
((NEUROMANCER . #<HASH-TABLE :TEST EQUAL :COUNT 1 {100959E273}>)
 (PATTERN-RECOGNITION . #<HASH-TABLE :TEST EQUAL :COUNT 1 {100959E6B3}>))

with-new-hash-table(htsyms &body body)
Create and bind a new hash table for each of the symbols in htsyms, executing inside a let form, and returns the hash table(s). If only one hash table is provided, return it as a single element; otherwise, return an alist of the symbol names and hash tables.