fix: allow empty newlines between in multiline messages (#125)

* fix: allow empty newlines between in multiline messages

Only works in websocket clients. TCP clients doesnt seems to work, at
least with emacs client.

Closes #109

* tests: add unit test for split with :empty-seqs t

* tests: check if formatted message is split with empty newlines

Author: ryukinix

src/server/base.lisp

@@ -135,16 +135,29 @@
       (push (copy-seq token) tokens))
     (nreverse tokens)))
 
-(defun split (string &key (delimiterp #'spacep) quotation-aware)
+(defun split-with-empty-seqs (string delimiterp)
+  "Slit a string maintaing empty strings when there is multiple consecutive delimiters"
+  (loop for start = 0 then (1+ pos)
+        for pos = (position-if delimiterp string :start start)
+        collect (subseq string start pos)
+        while pos))
+
+(defun split-trivial (string delimiterp)
+  (loop for beg = (position-if-not delimiterp string)
+          then (position-if-not delimiterp string :start (1+ end))
+        for end = (and beg (position-if delimiterp string :start beg))
+        when beg
+          collect (subseq string beg end)
+        while end))
+
+(defun split (string &key (delimiterp #'spacep) quotation-aware empty-seqs)
   "Split a string by a delimiterp function character checking"
-  (if (not quotation-aware)
-      (loop for beg = (position-if-not delimiterp string)
-              then (position-if-not delimiterp string :start (1+ end))
-            for end = (and beg (position-if delimiterp string :start beg))
-            when beg
-              collect (subseq string beg end)
-            while end)
-      (split-quotation-aware string delimiterp)))
+  (cond
+    ((and quotation-aware empty-seqs)
+     (error "QUOTATION-AWARE and WITH-EMTPY-SEQS cannot be used together"))
+    (quotation-aware (split-quotation-aware string delimiterp))
+    (empty-seqs (split-with-empty-seqs string delimiterp))
+    (t (split-trivial string delimiterp))))
 
 (defun startswith (string substring)
   "Check if STRING starts with SUBSTRING."
@@ -166,7 +179,7 @@
                        (message-time-hour-format message)))
          (from-str (message-from message))
          (content-str (message-content message))
-         (lines (split content-str :delimiterp (lambda (c) (char= c #\Newline)))))
+         (lines (split content-str :empty-seqs t :delimiterp (lambda (c) (char= c #\Newline)))))
     (format nil "~{~a~^~%~}"
             (mapcar (lambda (line)
                       (format-message-line time-str from-str line))

tests/unit.lisp

@@ -7,10 +7,10 @@
   :parent unit-tests
   (let ((time '(0 30 12 11 2 2026 2 nil 0))) ;; 2026-02-11 12:30:00 Wednesday GMT+0
     (is string= "12:30:00 of Wednesday, 2026-02-11 (GMT+0)"
-        (lisp-chat/server:format-time time))
-    (let ((msg (lisp-chat/server:make-message :from "test" :content "hi" :time time)))
-      (is string= "12:30:00" (lisp-chat/server:message-time-hour-format msg))
-      (is string= "2026-02-11 12:30:00" (lisp-chat/server:message-time-date-format msg)))))
+        (server:format-time time))
+    (let ((msg (server:make-message :from "test" :content "hi" :time time)))
+      (is string= "12:30:00" (server:message-time-hour-format msg))
+      (is string= "2026-02-11 12:30:00" (server:message-time-date-format msg)))))
 
 (define-test system-version-parsing
   :parent unit-tests
@@ -24,8 +24,24 @@
 
 (define-test commands-string-utils
   :parent unit-tests
-  (is equal '("x" "y" "z") (server:split "x.y.z"
-                                                      :delimiterp (lambda (c) (eql c #\.))))
-  (is equal '("foo" "bar zoo") (server:split "foo 'bar zoo'"
-                                                      :quotation-aware t))
+  (is equal
+      '("x" "y" "z")
+      (server:split "x.y.z"
+                    :delimiterp (lambda (c) (eql c #\.))))
+  (is equal
+      '("foo" "bar zoo")
+      (server:split "foo 'bar zoo'" :quotation-aware t))
+  (is equal
+      '("foo" "" "bar")
+      (server:split "foo  bar" :empty-seqs t))
   (true (server:startswith "/command" "/")))
+
+(define-test message-formatting
+  :parent unit-tests
+  (let* ((message (server:make-message :from "@server"
+                                       :content (format nil "line1~%~%xline2")
+                                       :time (server:get-time)))
+         (message-string (server:formatted-message message)))
+   (is equal
+       3
+       (count #\@ message-string :test #'char-equal))))