my-emacs-d/elpa/ht-20160806.1753/ht.el

305 lines
8.8 KiB
EmacsLisp

;;; ht.el --- The missing hash table library for Emacs
;; Copyright (C) 2013 Wilfred Hughes
;; Author: Wilfred Hughes <me@wilfred.me.uk>
;; Version: 2.2
;; Package-Version: 20160806.1753
;; Keywords: hash table, hash map, hash
;; Package-Requires: ((dash "2.12.0"))
;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with this program. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
;; The missing hash table library for Emacs.
;;
;; See documentation at https://github.com/Wilfred/ht.el
;;; Code:
(require 'dash)
(defmacro ht (&rest pairs)
"Create a hash table with the key-value pairs given.
Keys are compared with `equal'.
\(fn (KEY-1 VALUE-1) (KEY-2 VALUE-2) ...)"
(let* ((table-symbol (make-symbol "ht-temp"))
(assignments
(mapcar
(lambda (pair) `(ht-set! ,table-symbol ,@pair))
pairs)))
`(let ((,table-symbol (ht-create)))
,@assignments
,table-symbol)))
(defun ht-create (&optional test)
"Create an empty hash table.
TEST indicates the function used to compare the hash
keys. Default is `equal'. It can be `eq', `eql', `equal' or a
user-supplied test created via `define-hash-table-test'."
(make-hash-table :test (or test 'equal)))
(defun ht<-alist (alist &optional test)
"Create a hash table with initial values according to ALIST.
TEST indicates the function used to compare the hash
keys. Default is `equal'. It can be `eq', `eql', `equal' or a
user-supplied test created via `define-hash-table-test'."
(let ((h (ht-create test)))
;; the first key-value pair in an alist gets precedence, so we
;; start from the end of the list:
(dolist (pair (reverse alist) h)
(let ((key (car pair))
(value (cdr pair)))
(ht-set! h key value)))))
(defalias 'ht-from-alist 'ht<-alist)
;; based on the excellent -partition from dash.el, but we aim to be self-contained
(defun ht/group-pairs (list)
"Return a new list with the items in LIST grouped into pairs.
Errors if LIST doesn't contain an even number of elements."
(let ((result)
(sublist)
(len 0))
(while list
;; take the head of LIST and push onto SUBLIST
(setq sublist (cons (car list) sublist))
(setq list (cdr list))
(setq len (1+ len))
(when (= len 2)
;; push this two-item list onto RESULT
(setq result (cons (nreverse sublist) result))
(setq sublist nil)
(setq len 0)))
(when sublist (error "Expected an even number of elements"))
(nreverse result)))
(defun ht<-plist (plist &optional test)
"Create a hash table with initial values according to PLIST.
TEST indicates the function used to compare the hash
keys. Default is `equal'. It can be `eq', `eql', `equal' or a
user-supplied test created via `define-hash-table-test'."
(let ((h (ht-create test)))
(dolist (pair (ht/group-pairs plist) h)
(let ((key (car pair))
(value (cadr pair)))
(ht-set! h key value)))))
(defalias 'ht-from-plist 'ht<-plist)
(defun ht-get (table key &optional default)
"Look up KEY in TABLE, and return the matching value.
If KEY isn't present, return DEFAULT (nil if not specified)."
(gethash key table default))
(defun ht-set! (table key value)
"Associate KEY in TABLE with VALUE."
(puthash key value table)
nil)
(defalias 'ht-set 'ht-set!)
(defun ht-update! (table from-table)
"Update TABLE according to every key-value pair in FROM-TABLE."
(maphash
(lambda (key value) (puthash key value table))
from-table)
nil)
(defalias 'ht-update 'ht-update!)
(defun ht-merge (&rest tables)
"Crete a new tables that includes all the key-value pairs from TABLES.
If multiple have tables have the same key, the value in the last
table is used."
(let ((merged (ht-create)))
(mapc (lambda (table) (ht-update! merged table)) tables)
merged))
(defun ht-remove! (table key)
"Remove KEY from TABLE."
(remhash key table))
(defalias 'ht-remove 'ht-remove!)
(defun ht-clear! (table)
"Remove all keys from TABLE."
(clrhash table)
nil)
(defalias 'ht-clear 'ht-clear!)
(defun ht-map (function table)
"Apply FUNCTION to each key-value pair of TABLE, and make a list of the results.
FUNCTION is called with two arguments, KEY and VALUE."
(let (results)
(maphash
(lambda (key value)
(push (funcall function key value) results))
table)
results))
(defmacro ht-amap (form table)
"Anaphoric version of `ht-map'.
For every key-value pair in TABLE, evaluate FORM with the
variables KEY and VALUE bound."
`(ht-map (lambda (key value) ,form) ,table))
(defun ht-keys (table)
"Return a list of all the keys in TABLE."
(ht-amap key table))
(defun ht-values (table)
"Return a list of all the values in TABLE."
(ht-amap value table))
(defun ht-items (table)
"Return a list of two-element lists '(key value) from TABLE."
(ht-amap (list key value) table))
(defalias 'ht-each 'maphash
"Apply FUNCTION to each key-value pair of TABLE.
Returns nil, used for side-effects only.")
(defmacro ht-aeach (form table)
"Anaphoric version of `ht-each'.
For every key-value pair in TABLE, evaluate FORM with the
variables key and value bound."
`(ht-each (lambda (key value) ,form) ,table))
(defun ht->plist (table)
"Return a flat list '(key1 value1 key2 value2...) from TABLE.
Note that hash tables are unordered, so this cannot be an exact
inverse of `ht<-plist'. The following is not guaranteed:
\(let ((data '(a b c d)))
(equalp data
(ht->plist (ht<-plist data))))"
(apply 'append (ht-items table)))
(defalias 'ht-to-plist 'ht->plist)
(defun ht-copy (table)
"Return a shallow copy of TABLE (keys and values are shared)."
(copy-hash-table table))
(defun ht->alist (table)
"Return a list of two-element lists '(key . value) from TABLE.
Note that hash tables are unordered, so this cannot be an exact
inverse of `ht<-alist'. The following is not guaranteed:
\(let ((data '((a . b) (c . d))))
(equalp data
(ht->alist (ht<-alist data))))"
(ht-amap (cons key value) table))
(defalias 'ht-to-alist 'ht->alist)
(defalias 'ht? 'hash-table-p)
(defalias 'ht-p 'hash-table-p)
(defun ht-contains? (table key)
"Return 't if TABLE contains KEY."
(not (eq (ht-get table key 'ht--not-found) 'ht--not-found)))
(defalias 'ht-contains-p 'ht-contains?)
(defun ht-size (table)
"Return the actual number of entries in TABLE."
(hash-table-count table))
(defun ht-empty? (table)
"Return true if the actual number of entries in TABLE is zero."
(zerop (ht-size table)))
(defun ht-select (function table)
"Return a hash table containing all entries in TABLE for which
FUNCTION returns a truthy value.
FUNCTION is called with two arguments, KEY and VALUE."
(let ((results (ht-create)))
(ht-each
(lambda (key value)
(when (funcall function key value)
(ht-set! results key value)))
table)
results))
(defun ht-reject (function table)
"Return a hash table containing all entries in TABLE for which
FUNCTION returns a falsy value.
FUNCTION is called with two arguments, KEY and VALUE."
(let ((results (ht-create)))
(ht-each
(lambda (key value)
(unless (funcall function key value)
(ht-set! results key value)))
table)
results))
(defun ht-reject! (function table)
"Delete entries from TABLE for which FUNCTION returns a falsy value.
FUNCTION is called with two arguments, KEY and VALUE."
(ht-each
(lambda (key value)
(when (funcall function key value)
(remhash key table)))
table)
nil)
(defalias 'ht-delete-if 'ht-reject!)
(defun ht-find (function table)
"Return (key, value) from TABLE for which FUNCTION returns a truthy value.
Return nil otherwise.
FUNCTION is called with two arguments, KEY and VALUE."
(catch 'break
(ht-each
(lambda (key value)
(when (funcall function key value)
(throw 'break (list key value))))
table)))
(defun ht-equal? (table1 table2)
"Return t if TABLE1 and TABLE2 have the same keys and values.
Does not compare equality predicates."
(let ((keys1 (ht-keys table1))
(keys2 (ht-keys table2))
(sentinel (make-symbol "ht-sentinel")))
(and (equal (length keys1) (length keys2))
(--all?
(equal (ht-get table1 it)
(ht-get table2 it sentinel))
keys1))))
(defalias 'ht-equal-p 'ht-equal?)
(provide 'ht)
;;; ht.el ends here