Add core plist library

core/autoload/plist.el

@@ -0,0 +1,84 @@
+;;; ../work/conf/doom-emacs/core/autoload/plist.el -*- lexical-binding: t; -*-
+
+;;;###autoload
+(defun doom-plist-get (plist prop &optional nil-value)
+  "Return PROP in PLIST, if it exists. Otherwise NIL-VALUE."
+  (if-let (val (plist-member plist prop))
+      (cadr val)
+    nil-value))
+
+;;;###autoload
+(defun doom-plist-merge (from-plist to-plist)
+  "Destructively merge FROM-PLIST onto TO-PLIST"
+  (while plist
+    (plist-put! old-plist (pop plist) (pop plist))))
+
+;;;###autoload
+(defun doom-plist-delete-nil (plist)
+  "Delete `nil' properties from a copy of PLIST."
+  (let (p)
+    (while plist
+      (if (car plist)
+          (setq p (plist-put p (car plist) (nth 1 plist))))
+      (setq plist (cddr plist)))
+    p))
+
+;;;###autoload
+(defun doom-plist-delete (plist prop)
+  "Delete PROP from a copy of PLIST."
+  (let (p)
+    (while plist
+      (if (not (eq prop (car plist)))
+          (setq p (plist-put p (car plist) (nth 1 plist))))
+      (setq plist (cddr plist)))
+    p))
+
+
+;;
+;;; Macros
+
+;;;###autoload
+(cl-defmacro doplist! ((arglist plist &optional retval) &rest body)
+  "Loop over a PLIST's (property value) pairs then return RETVAL.
+
+Evaluate BODY with either ARGLIST bound to (cons PROP VAL) or, if ARGLIST is a
+list, the pair is destructured into (CAR . CDR)."
+  (declare (indent defun))
+  (let ((plist-var (make-symbol "plist")))
+    `(let ((,plist-var ,plist))
+       (while ,plist-var
+         (let ,(if (listp arglist)
+                   `((,(pop arglist) (pop ,plist-var))
+                     (,(pop arglist) (pop ,plist-var)))
+                 `((,arglist (cons (pop ,plist-var)
+                                   (pop ,plist-var)))))
+           ,@body)))))
+
+;;;###autoload
+(defmacro plist-put! (plist prop value)
+  "Set PROP to VALUE in PLIST in-place."
+  (let ((plist-var (make-symbol "plist")))
+    `(setq ,plist (plist-put ,plist ,prop ,value))))
+
+;;;###autoload
+(defmacro plist-delete! (plist prop)
+  "Delete PROP from PLIST in-place."
+  `(setq ,plist (doom-plist-delete ,plist ,prop)))
+
+;;;###autoload
+(defmacro with-plist! (plist props &rest body)
+  "With props bound from PLIST to PROPS, evaluate BODY.
+
+PROPS is a list of symbols. Each one is converted to a keyword and then its
+value is looked up in the PLIST and bound to the symbol for the duration of
+BODY."
+  (declare (indent 2))
+  (let ((plist-sym (make-symbol "plist")))
+    `(let* ((,plist-sym ,plist)
+            ,@(cl-loop for prop in props
+                       collect
+                       `(,prop
+                         (plist-get
+                          ,plist-sym
+                          ,(doom-keyword-intern (symbol-name prop))))))
+       ,@body)))