[elpa] externals/dict-tree 753904c 034/154: Added functions for pushing things onto dictree and trie stacks

[Stefan Monnier]

branch: externals/dict-tree
commit 753904c8e155299a4f510f8b5cf0d8cef69020be
Author: Toby Cubitt <toby-predictive@dr-qubit.org>
Commit: tsc25 <toby-predictive@dr-qubit.org>

    Added functions for pushing things onto dictree and trie stacks
---
 dict-tree.el | 46 +++++++++++++++++++++++++++++++++++++---------
 1 file changed, 37 insertions(+), 9 deletions(-)

diff --git a/dict-tree.el b/dict-tree.el
index 3ab34a9..b7088e6 100644
--- a/dict-tree.el
+++ b/dict-tree.el
@@ -1568,6 +1568,7 @@ bind any variables with names commencing \"--\"."
                  (heap (heap-create
                         (dictree--construct-meta-stack-heapfun sortfun)
                         (length (dictree--trielist dict))))
+                 (pushed '())
                  (dummy (mapc
                          (lambda (dic)
                            (heap-add heap (trie-stack dic type reverse)))
@@ -1582,6 +1583,7 @@ bind any variables with names commencing \"--\"."
                         (dictree--construct-meta-stack-heapfun
                          sortfun reverse)
                         (length (dictree--trielist dict))))
+                 (pushed '())
                  (dummy (mapc
                          (lambda (trie)
                            (let ((stack (trie-complete-stack
@@ -1590,7 +1592,7 @@ bind any variables with names commencing \"--\"."
                                (heap-add heap stack))))
                          (dictree--trielist dict)))))
    (:copier nil))
-  combfun sortfun heap)
+  combfun sortfun heap pushed)
 
 
 
@@ -1668,22 +1670,46 @@ sufficient, it is better to use one of those instead."
 (defun dictree-stack-pop (dictree-stack)
   "Pop the first element from the DICTREE-STACK.
 Returns nil if the stack is empty."
-  (let ((popped (dictree--stack-pop dictree-stack)))
-    (when popped (cons (car popped) (dictree--cell-data (cdr popped))))))
+  (cond
+   ;; if elements have been pushed onto a dict stack, pop those first
+   ;; FIXME: shouldn't be using internal trie functions!
+   ((and (trie-stack-p dictree-stack) (trie--stack-pushed dictree-stack))
+    (trie-stack-pop dictree-stack))
+   ;; if elements have been pushed onto a meta-dict stack, pop those first
+   ((and (dictree--meta-stack-p dictree-stack)
+        (dictree--meta-stack-pushed dictree-stack))
+    (pop (dictree--meta-stack-pushed dictree-stack)))
+   ;; otherwise, pop first element from dictree-stack
+   (t (let ((popped (dictree--stack-pop dictree-stack)))
+       (when popped (cons (car popped) (dictree--cell-data (cdr popped))))))
+   ))
+
+
+(defun dictree-stack-push (element dictree-stack)
+  "Push ELEMENT onto DICTREE-STACK."
+  (if (trie-stack-p dictree-stack)
+      (trie-stack-push element dictree-stack)  ; normal dict
+    (push element (dictree--meta-stack-pushed dictree-stack))))  ;  meta-dict
 
 
 (defun dictree-stack-first (dictree-stack)
   "Return the first element from DICTREE-STACK, without removing it.
 Returns nil if the stack is empty."
-  (let ((first (dictree--stack-first dictree-stack)))
-    (cons (car first) (dictree--cell-data (cdr first)))))
+  ;; if elements have been pushed onto the stack, return first of those
+  (if (and (dictree--meta-stack-p dictree-stack)
+          (dictree--meta-stack-pushed dictree-stack))
+      (car (dictree--meta-stack-pushed dictree-stack))
+    ;; otherwise, return first element from dictree-stack
+    (let ((first (dictree--stack-first dictree-stack)))
+      (cons (car first) (dictree--cell-data (cdr first))))))
 
 
 (defun dictree-stack-empty-p (dictree-stack)
   "Return t if DICTREE-STACK is empty, nil otherwise."
   (if (trie-stack-p dictree-stack)
       (trie-stack-empty-p dictree-stack)  ; normal dict
-    (heap-empty (dictree--meta-stack-heap dictree-stack))))  ; meta--dict
+    (and (heap-empty (dictree--meta-stack-heap dictree-stack))  ; meta-dict
+        (null (dictree--meta-stack-pushed dictree-stack)))))
 
 
 (defun dictree--stack-first (dictree-stack)
@@ -1693,8 +1719,10 @@ Returns nil if the stack is empty."
       ;; normal dict
       (trie-stack-first dictree-stack)
     ;; meta-dict
-    (dictree--stack-first
-     (heap-root (dictree--meta-stack-heap dictree-stack)))))
+    (if (dictree--meta-stack-pushed dictree-stack)
+       (car (dictree--meta-stack-pushed dictree-stack))  ; pushed element
+      (dictree--stack-first                        ; dictree-stack element
+       (heap-root (dictree--meta-stack-heap dictree-stack))))))
 
 
 (defun dictree--stack-pop (dictree-stack)
@@ -1716,7 +1744,7 @@ Returns nil if the stack is empty."
        (setq stack (heap-delete-root heap))
        (setq curr (dictree--stack-pop stack))
        (unless (dictree-stack-empty-p stack) (heap-add heap stack))
-       ;; peek at the first element of the new stack at the root of the heap
+       ;; peek at the first element of the stack now at the root of the heap
        (unless (heap-empty heap)
          (setq next (dictree--stack-first (heap-root heap)))
          ;; repeat this as long as we keep finding elements with the same key,