Make -if-let and -when-let families destructure their arguments

dash.el

@@ -1116,68 +1116,61 @@ sorts it in descending order."
 
 (defmacro -when-let (var-val &rest body)
   "If VAL evaluates to non-nil, bind it to VAR and execute body.
-VAR-VAL should be a (VAR VAL) pair."
+VAR-VAL should be a (VAR VAL) pair.
+
+Note: binding is done according to `-let'."
   (declare (debug ((symbolp form) body))
            (indent 1))
-  (let ((var (car var-val))
-        (val (cadr var-val)))
-    `(let ((,var ,val))
-       (when ,var
-         ,@body))))
+  `(-if-let ,var-val (progn ,@body)))
 
 (defmacro -when-let* (vars-vals &rest body)
   "If all VALS evaluate to true, bind them to their corresponding
 VARS and execute body. VARS-VALS should be a list of (VAR VAL)
-pairs (corresponding to bindings of `let*')."
+pairs.
+
+Note: binding is done according to `-let'."
   (declare (debug ((&rest (symbolp form)) body))
            (indent 1))
-  (if (= (length vars-vals) 1)
-      `(-when-let ,(car vars-vals)
-         ,@body)
-    `(-when-let ,(car vars-vals)
-       (-when-let* ,(cdr vars-vals)
-         ,@body))))
+  `(-if-let* ,vars-vals (progn ,@body)))
 
 (defmacro --when-let (val &rest body)
   "If VAL evaluates to non-nil, bind it to `it' and execute
 body."
   (declare (debug (form body))
            (indent 1))
-  `(let ((it ,val))
-     (when it
-       ,@body)))
+  `(--if-let ,val (progn ,@body)))
 
 (defmacro -if-let (var-val then &rest else)
   "If VAL evaluates to non-nil, bind it to VAR and do THEN,
-otherwise do ELSE. VAR-VAL should be a (VAR VAL) pair."
+otherwise do ELSE. VAR-VAL should be a (VAR VAL) pair.
+
+Note: binding is done according to `-let'."
   (declare (debug ((symbolp form) form body))
            (indent 2))
-  (let ((var (car var-val))
-        (val (cadr var-val)))
-    `(let ((,var ,val))
-       (if ,var ,then ,@else))))
+  `(-if-let* (,var-val) ,then ,@else))
 
 (defmacro -if-let* (vars-vals then &rest else)
   "If all VALS evaluate to true, bind them to their corresponding
 VARS and do THEN, otherwise do ELSE. VARS-VALS should be a list
-of (VAR VAL) pairs (corresponding to the bindings of `let*')."
+of (VAR VAL) pairs.
+
+Note: binding is done according to `-let'."
   (declare (debug ((&rest (symbolp form)) form body))
            (indent 2))
-  (let ((first-pair (car vars-vals))
-        (rest (cdr vars-vals)))
-    (if (= (length vars-vals) 1)
-        `(-if-let ,first-pair ,then ,@else)
-      `(-if-let ,first-pair
-         (-if-let* ,rest ,then ,@else)
-         ,@else))))
+  (->> vars-vals
+    (-mapcat (-lambda ((pat src)) (dash--match pat src)))
+    (-reduce-r-from
+     (-lambda ((var val) memo)
+       `(let ((,var ,val))
+          (if ,var ,memo ,@else)))
+     then)))
 
 (defmacro --if-let (val then &rest else)
   "If VAL evaluates to non-nil, bind it to `it' and do THEN,
 otherwise do ELSE."
   (declare (debug (form form body))
            (indent 2))
-  `(let ((it ,val))
-     (if it ,then ,@else)))
+  `(-if-let (it ,val) ,then ,@else))
 
 (defun dash--match-ignore-place-p (symbol)
   "Return non-nil if SYMBOL is a symbol and starts with _."