[Emacs-diffs] master 17d667b: Add seq-intersection and seq-difference to the seq library

[Nicolas Petton]

branch: master
commit 17d667b3876920652152baa4eab24134940a0f30
Author: Nicolas Petton <address@hidden>
Commit: Nicolas Petton <address@hidden>

    Add seq-intersection and seq-difference to the seq library
    
    * lisp/emacs-lisp/seq.el (seq-intersection, seq-difference): New
    functions.
    
    * test/automated/seq-tests.el: Add tests for seq-intersection and
    seq-difference.
    
    * doc/lispref/sequences.texi: Add documentation for seq-intersection
    and seq-difference.
---
 doc/lispref/sequences.texi  |   30 +++++++++++++++++++++++++++++-
 lisp/emacs-lisp/seq.el      |   29 ++++++++++++++++++++++++++++-
 test/automated/seq-tests.el |   26 ++++++++++++++++++++++++++
 3 files changed, 83 insertions(+), 2 deletions(-)

diff --git a/doc/lispref/sequences.texi b/doc/lispref/sequences.texi
index 1af3535..334b347 100644
--- a/doc/lispref/sequences.texi
+++ b/doc/lispref/sequences.texi
@@ -723,6 +723,35 @@ contain less elements than @var{n}.  @var{n} must be an 
integer.  If
 @end example
 @end defun
 
address@hidden seq-intersection sequence1 sequence2 &optional function
+  This function returns a list of the elements that appear both in
address@hidden and @var{sequence2}.  If the optional argument
address@hidden is address@hidden, it is a function of two arguments to
+use to compare elements instead of the default @code{equal}.
+
address@hidden
address@hidden
+(seq-intersection [2 3 4 5] [1 3 5 6 7])
address@hidden {} (3 5)
address@hidden group
address@hidden example
address@hidden defun
+
+
address@hidden seq-difference sequence1 sequence2 &optional function
+  This function returns a list of the elements that appear in
address@hidden but not in @var{sequence2}.  If the optional argument
address@hidden is address@hidden, it is a function of two arguments to
+use to compare elements instead of the default @code{equal}.
+
address@hidden
address@hidden
+(seq-difference '(2 3 4 5) [1 3 5 6 7])
address@hidden {} (2 4)
address@hidden group
address@hidden example
address@hidden defun
+
 @defun seq-group-by function sequence
   This function separates the elements of @var{sequence} into an alist
 whose keys are the result of applying @var{function} to each element
@@ -761,7 +790,6 @@ of type @var{type}.  @var{type} can be one of the following 
symbols:
 @end example
 @end defun
 
-
 @defmac seq-doseq (var sequence [result]) address@hidden
 @cindex sequence iteration
   This macro is like @code{dolist}, except that @var{sequence} can be a list,
diff --git a/lisp/emacs-lisp/seq.el b/lisp/emacs-lisp/seq.el
index c5f5906..6f7f3c4 100644
--- a/lisp/emacs-lisp/seq.el
+++ b/lisp/emacs-lisp/seq.el
@@ -4,7 +4,7 @@
 
 ;; Author: Nicolas Petton <address@hidden>
 ;; Keywords: sequences
-;; Version: 1.3
+;; Version: 1.4
 ;; Package: seq
 
 ;; Maintainer: address@hidden
@@ -240,6 +240,26 @@ negative integer or 0, nil is returned."
         (setq seq (seq-drop seq n)))
       (nreverse result))))
 
+(defun seq-intersection (seq1 seq2 &optional testfn)
+  "Return a list of the elements that appear in both SEQ1 and SEQ2.
+Equality is defined by TESTFN if non-nil or by `equal' if nil."
+  (seq-reduce (lambda (acc elt)
+                (if (seq-contains-p seq2 elt testfn)
+                    (cons elt acc)
+                  acc))
+              (seq-reverse seq1)
+              '()))
+
+(defun seq-difference (seq1 seq2 &optional testfn)
+  "Return a list of th elements that appear in SEQ1 but not in SEQ2.
+Equality is defined by TESTFN if non-nil or by `equal' if nil."
+  (seq-reduce (lambda (acc elt)
+                (if (not (seq-contains-p seq2 elt testfn))
+                    (cons elt acc)
+                  acc))
+              (seq-reverse seq1)
+              '()))
+
 (defun seq-group-by (function seq)
   "Apply FUNCTION to each element of SEQ.
 Separate the elements of SEQ into an alist using the results as
@@ -318,6 +338,11 @@ This is an optimization for lists in `seq-take-while'."
       (setq n (+ 1 n)))
     n))
 
+(defun seq--activate-font-lock-keywords ()
+  "Activate font-lock keywords for some symbols defined in seq."
+  (font-lock-add-keywords 'emacs-lisp-mode
+                          '("\\<seq-doseq\\>")))
+
 (defalias 'seq-copy #'copy-sequence)
 (defalias 'seq-elt #'elt)
 (defalias 'seq-length #'length)
@@ -325,5 +350,7 @@ This is an optimization for lists in `seq-take-while'."
 (defalias 'seq-each #'seq-do)
 (defalias 'seq-map #'mapcar)
 
+(add-to-list 'emacs-lisp-mode-hook #'seq--activate-font-lock-keywords)
+
 (provide 'seq)
 ;;; seq.el ends here
diff --git a/test/automated/seq-tests.el b/test/automated/seq-tests.el
index d3536b6..7f6e06c 100644
--- a/test/automated/seq-tests.el
+++ b/test/automated/seq-tests.el
@@ -250,5 +250,31 @@ Evaluate BODY for each created sequence.
     (should (same-contents-p list vector))
     (should (vectorp vector))))
 
+(ert-deftest test-seq-intersection ()
+  (let ((v1 [2 3 4 5])
+        (v2 [1 3 5 6 7]))
+    (should (same-contents-p (seq-intersection v1 v2)
+                             '(3 5))))
+  (let ((l1 '(2 3 4 5))
+        (l2 '(1 3 5 6 7)))
+    (should (same-contents-p (seq-intersection l1 l2)
+                             '(3 5))))
+  (let ((v1 [2 4 6])
+        (v2 [1 3 5]))
+    (should (seq-empty-p (seq-intersection v1 v2)))))
+
+(ert-deftest test-seq-difference ()
+  (let ((v1 [2 3 4 5])
+        (v2 [1 3 5 6 7]))
+    (should (same-contents-p (seq-difference v1 v2)
+                             '(2 4))))
+  (let ((l1 '(2 3 4 5))
+        (l2 '(1 3 5 6 7)))
+    (should (same-contents-p (seq-difference l1 l2)
+                             '(2 4))))
+  (let ((v1 [2 4 6])
+        (v2 [2 4 6]))
+    (should (seq-empty-p (seq-difference v1 v2)))))
+
 (provide 'seq-tests)
 ;;; seq-tests.el ends here