(require 'seq)
+(pcase-defmacro map (&rest args)
+ "pcase pattern matching map elements.
+Matches if the object is a map (list, hash-table or array), and
+binds values from ARGS to their corresponding elements of the map.
+
+ARGS can be a list elements of the form (KEY PAT), in which case
+KEY in an unquoted form.
+
+ARGS can also be a list of symbols, which stands for ('SYMBOL
+SYMBOL)."
+ `(and (pred map-p)
+ ,@(map--make-pcase-bindings args)))
+
+(defmacro map-let (keys map &rest body)
+ "Bind the variables in KEYS to the elements of MAP then evaluate BODY.
+
+KEYS can be a list of symbols, in which case each element will be
+bound to the looked up value in MAP.
+
+KEYS can also be a list of (KEY VARNAME) pairs, in which case
+KEY is an unquoted form.
+
+MAP can be a list, hash-table or array."
+ (declare (indent 2) (debug t))
+ `(pcase-let ((,(map--make-pcase-patterns keys) ,map))
+ ,@body))
+
+(eval-when-compile
+ (defmacro map--dispatch (map-var &rest args)
+ "Evaluate one of the forms specified by ARGS based on the type of MAP.
+
+The following keyword types are meaningful: `:list',
+`:hash-table' and `:array'.
+
+An error is thrown if MAP is neither a list, hash-table nor array.
+
+Return RESULT if non-nil or the result of evaluation of the form."
+ (declare (debug t) (indent 1))
+ `(cond ((listp ,map-var) ,(plist-get args :list))
+ ((hash-table-p ,map-var) ,(plist-get args :hash-table))
+ ((arrayp ,map-var) ,(plist-get args :array))
+ (t (error "Unsupported map: %s" ,map-var)))))
+
(defun map-elt (map key &optional default)
"Perform a lookup in MAP of KEY and return its associated value.
If KEY is not found, return DEFAULT which defaults to nil.
-If MAP is a list, `equal' is used to lookup KEY."
+If MAP is a list, `eql' is used to lookup KEY.
+
+MAP can be a list, hash-table or array."
+ (declare
+ (gv-expander
+ (lambda (do)
+ (gv-letplace (mgetter msetter) `(gv-delay-error ,map)
+ (macroexp-let2* nil
+ ;; Eval them once and for all in the right order.
+ ((key key) (default default))
+ `(if (listp ,mgetter)
+ ;; Special case the alist case, since it can't be handled by the
+ ;; map--put function.
+ ,(gv-get `(alist-get ,key (gv-synthetic-place
+ ,mgetter ,msetter)
+ ,default)
+ do)
+ ,(funcall do `(map-elt ,mgetter ,key ,default)
+ (lambda (v) `(map--put ,mgetter ,key ,v)))))))))
(map--dispatch map
- :list (or (cdr (assoc key map)) default)
+ :list (alist-get key map default)
:hash-table (gethash key map default)
- :array (map--elt-array map key default)))
+ :array (if (and (>= key 0) (< key (seq-length map)))
+ (seq-elt map key)
+ default)))
(defmacro map-put (map key value)
"In MAP, associate KEY with VALUE and return MAP.
If KEY is already present in MAP, replace the associated value
-with VALUE."
- (declare (debug t))
- `(progn
- (map--dispatch (m ,map m)
- :list (setq ,map (cons (cons ,key ,value) m))
- :hash-table (puthash ,key ,value m)
- :array (aset m ,key ,value))))
+with VALUE.
+
+MAP can be a list, hash-table or array."
+ (macroexp-let2 nil map map
+ `(progn
+ (setf (map-elt ,map ,key) ,value)
+ ,map)))
(defmacro map-delete (map key)
"In MAP, delete the key KEY if present and return MAP.
-If MAP is an array, store nil at the index KEY."
+If MAP is an array, store nil at the index KEY.
+
+MAP can be a list, hash-table or array."
(declare (debug t))
- `(progn
- (map--dispatch (m ,map m)
- :list (setq ,map (map--delete-alist m ,key))
- :hash-table (remhash ,key m)
- :array (aset m ,key nil))))
+ (gv-letplace (mgetter msetter) `(gv-delay-error ,map)
+ (macroexp-let2 nil key key
+ `(if (not (listp ,mgetter))
+ (map--delete ,mgetter ,key)
+ ;; The alist case is special, since it can't be handled by the
+ ;; map--delete function.
+ (setf (alist-get ,key (gv-synthetic-place ,mgetter ,msetter)
+ nil t)
+ nil)
+ ,mgetter))))
(defun map-nested-elt (map keys &optional default)
- "Travserse MAP using KEYS and return the looked up value or DEFAULT if nil.
+ "Traverse MAP using KEYS and return the looked up value or DEFAULT if nil.
+
Map can be a nested map composed of alists, hash-tables and arrays."
(or (seq-reduce (lambda (acc key)
(when (map-p acc)
default))
(defun map-keys (map)
- "Return the list of keys in MAP."
+ "Return the list of keys in MAP.
+
+MAP can be a list, hash-table or array."
(map-apply (lambda (key _) key) map))
(defun map-values (map)
- "Return the list of values in MAP."
+ "Return the list of values in MAP.
+
+MAP can be a list, hash-table or array."
(map-apply (lambda (_ value) value) map))
(defun map-pairs (map)
- "Return the elements of MAP as key/value association lists."
- (map-apply (lambda (key value)
- (cons key value))
- map))
+ "Return the elements of MAP as key/value association lists.
+
+MAP can be a list, hash-table or array."
+ (map-apply #'cons map))
(defun map-length (map)
- "Return the length of MAP."
+ "Return the length of MAP.
+
+MAP can be a list, hash-table or array."
(length (map-keys map)))
(defun map-copy (map)
- "Return a copy of MAP."
+ "Return a copy of MAP.
+
+MAP can be a list, hash-table or array."
(map--dispatch map
:list (seq-copy map)
:hash-table (copy-hash-table map)
:array (seq-copy map)))
(defun map-apply (function map)
- "Return the result of applying FUNCTION to each element of MAP.
-FUNCTION is called with two arguments, the key and the value."
+ "Apply FUNCTION to each element of MAP and return the result as a list.
+FUNCTION is called with two arguments, the key and the value.
+
+MAP can be a list, hash-table or array."
(funcall (map--dispatch map
:list #'map--apply-alist
:hash-table #'map--apply-hash-table
map))
(defun map-keys-apply (function map)
- "Return the result of applying FUNCTION to each key of MAP."
+ "Return the result of applying FUNCTION to each key of MAP.
+
+MAP can be a list, hash-table or array."
(map-apply (lambda (key _)
(funcall function key))
map))
(defun map-values-apply (function map)
- "Return the result of applying FUNCTION to each value of MAP."
+ "Return the result of applying FUNCTION to each value of MAP.
+
+MAP can be a list, hash-table or array."
(map-apply (lambda (_ val)
(funcall function val))
map))
(defun map-filter (pred map)
- "Return an alist of the key/val pairs of which (PRED key val) is non-nil in MAP."
+ "Return an alist of key/val pairs for which (PRED key val) is non-nil in MAP.
+
+MAP can be a list, hash-table or array."
(delq nil (map-apply (lambda (key val)
(if (funcall pred key val)
(cons key val)
map)))
(defun map-remove (pred map)
- "Return an alist of the key/val pairs of which (PRED key val) is nil in MAP."
+ "Return an alist of the key/val pairs for which (PRED key val) is nil in MAP.
+
+MAP can be a list, hash-table or array."
(map-filter (lambda (key val) (not (funcall pred key val)))
map))
(defun map-empty-p (map)
"Return non-nil is MAP is empty.
+
MAP can be a list, hash-table or array."
- (null (map-keys map)))
+ (map--dispatch map
+ :list (null map)
+ :array (seq-empty-p map)
+ :hash-table (zerop (hash-table-count map))))
-(defun map-contains-key-p (map key &optional testfn)
+(defun map-contains-key (map key &optional testfn)
"Return non-nil if MAP contain the key KEY, nil otherwise.
Equality is defined by TESTFN if non-nil or by `equal' if nil.
+
MAP can be a list, hash-table or array."
- (seq-contains-p (map-keys map) key testfn))
+ (seq-contains (map-keys map) key testfn))
+
+(defun map-some (pred map)
+ "Return a non-nil if (PRED key val) is non-nil for any key/value pair in MAP.
-(defun map-some-p (pred map)
- "Return any key/value pair for which (PRED key val) is non-nil is MAP."
+MAP can be a list, hash-table or array."
(catch 'map--break
(map-apply (lambda (key value)
(when (funcall pred key value)
nil))
(defun map-every-p (pred map)
- "Return non-nil if (PRED key val) is non-nil for all elements of the map MAP."
+ "Return non-nil if (PRED key val) is non-nil for all elements of the map MAP.
+
+MAP can be a list, hash-table or array."
(catch 'map--break
(map-apply (lambda (key value)
(or (funcall pred key value)
t))
(defun map-merge (type &rest maps)
- "Merge into a map of type TYPE all the key/value pairs in the maps MAPS."
+ "Merge into a map of type TYPE all the key/value pairs in the maps MAPS.
+
+MAP can be a list, hash-table or array."
(let (result)
(while maps
(map-apply (lambda (key value)
- (map-put result key value))
+ (setf (map-elt result key) value))
(pop maps)))
(map-into result type)))
(defun map-into (map type)
"Convert the map MAP into a map of type TYPE.
-TYPE can be one of the following symbols: list or hash-table."
+
+TYPE can be one of the following symbols: list or hash-table.
+MAP can be a list, hash-table or array."
(pcase type
(`list (map-pairs map))
(`hash-table (map--into-hash-table map))
- (t (error "Not a map type name: %S" type))))
-
-(defmacro map--dispatch (spec &rest args)
- "Evaluate one of the provided forms depending on the type of MAP.
+ (_ (error "Not a map type name: %S" type))))
-SPEC can be a map or a list of the form (VAR MAP [RESULT]).
-ARGS should have the form [TYPE FORM]...
-
-The following keyword types are meaningful: `:list',
-`:hash-table' and `array'.
-
-An error is thrown if MAP is neither a list, hash-table or array.
-
-Return RESULT if non-nil or the result of evaluation of the
-form.
-
-\(fn (VAR MAP [RESULT]) &rest ARGS)"
- (declare (debug t) (indent 1))
- (unless (listp spec)
- (setq spec `(,spec ,spec)))
- (let ((map-var (car spec))
- (result-var (make-symbol "result")))
- `(let ((,map-var ,(cadr spec))
- ,result-var)
- (setq ,result-var
- (cond ((listp ,map-var) ,(plist-get args :list))
- ((hash-table-p ,map-var) ,(plist-get args :hash-table))
- ((arrayp ,map-var) ,(plist-get args :array))
- (t (error "Unsupported map: %s" ,map-var))))
- ,@(when (cddr spec)
- `((setq ,result-var ,@(cddr spec))))
- ,result-var)))
+(defun map--put (map key v)
+ (map--dispatch map
+ :list (let ((p (assoc key map)))
+ (if p (setcdr p v)
+ (error "No place to change the mapping for %S" key)))
+ :hash-table (puthash key v map)
+ :array (aset map key v)))
(defun map--apply-alist (function map)
"Private function used to apply FUNCTION over MAP, MAP being an alist."
(cdr pair)))
map))
+(defun map--delete (map key)
+ (map--dispatch map
+ :list (error "No place to remove the mapping for %S" key)
+ :hash-table (remhash key map)
+ :array (and (>= key 0)
+ (<= key (seq-length map))
+ (aset map key nil)))
+ map)
+
(defun map--apply-hash-table (function map)
"Private function used to apply FUNCTION over MAP, MAP being a hash-table."
(let (result)
(defun map--apply-array (function map)
"Private function used to apply FUNCTION over MAP, MAP being an array."
- (let ((index 0))
- (seq-map (lambda (elt)
- (prog1
- (funcall function index elt)
- (setq index (1+ index))))
- map)))
-
-(defun map--elt-array (map key &optional default)
- "Return the element of the arary MAP at the index KEY, or DEFAULT if nil."
- (let ((len (seq-length map)))
- (or (and (>= key 0)
- (<= key len)
- (seq-elt map key))
- default)))
-
-
-(defun map--delete-alist (map key)
- "Return MAP with KEY removed."
- (seq-remove (lambda (pair)
- (equal key (car pair)))
- map))
+ (let ((index 0))
+ (seq-map (lambda (elt)
+ (prog1
+ (funcall function index elt)
+ (setq index (1+ index))))
+ map)))
(defun map--into-hash-table (map)
"Convert MAP into a hash-table."
(let ((ht (make-hash-table :size (map-length map)
:test 'equal)))
(map-apply (lambda (key value)
- (map-put ht key value))
+ (setf (map-elt ht key) value))
map)
ht))
+(defun map--make-pcase-bindings (args)
+ "Return a list of pcase bindings from ARGS to the elements of a map."
+ (seq-map (lambda (elt)
+ (if (consp elt)
+ `(app (pcase--flip map-elt ,(car elt)) ,(cadr elt))
+ `(app (pcase--flip map-elt ',elt) ,elt)))
+ args))
+
+(defun map--make-pcase-patterns (args)
+ "Return a list of `(map ...)' pcase patterns built from ARGS."
+ (cons 'map
+ (seq-map (lambda (elt)
+ (if (and (consp elt) (eq 'map (car elt)))
+ (map--make-pcase-patterns elt)
+ elt))
+ args)))
+
(provide 'map)
;;; map.el ends here