From 4e3eb738b47cd12bc78ed3fbf43796a8280c73aa Mon Sep 17 00:00:00 2001
From: Aditya <ntgmuch01@gmail.com>
Date: Sun, 30 Aug 2026 22:25:23 +0530
Subject: [PATCH] fix: allow style switching back to Beamer without saving

---
 TeXmacs/progs/generic/document-style.scm    | 11 ++++++++++-
 TeXmacs/progs/generic/test/generic-test.scm | 21 ++++++++++++++++++++-
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/TeXmacs/progs/generic/document-style.scm b/TeXmacs/progs/generic/document-style.scm
index 9de85fd167..d6e338c89d 100644
--- a/TeXmacs/progs/generic/document-style.scm
+++ b/TeXmacs/progs/generic/document-style.scm
@@ -115,6 +115,13 @@
   ) ;when
 ) ;tm-define
 
+(tm-define (beamer-style-switch-allowed?)
+  (or (document-empty?)
+      (buffer-modified? (current-buffer))
+      (has-main-style? "beamer")
+  ) ;or
+) ;tm-define
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; High level routines for style and style package management
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -140,7 +147,9 @@
   (:default style "generic")
   (:check-mark "v" has-main-style?)
   (:balloon style-get-documentation)
-  (if (and (== style "beamer") (not (document-empty?)))
+  (if (and (== style "beamer")
+           (not (beamer-style-switch-allowed?))
+      ) ;and
     (show-message "Switching non-empty documents to Beamer style is not supported"
       "Cannot switch style"
     ) ;show-message
diff --git a/TeXmacs/progs/generic/test/generic-test.scm b/TeXmacs/progs/generic/test/generic-test.scm
index 2060a2a5b5..413b11433c 100644
--- a/TeXmacs/progs/generic/test/generic-test.scm
+++ b/TeXmacs/progs/generic/test/generic-test.scm
@@ -32,8 +32,27 @@
   (check (focus-tag-name 'big-table) => "big table")
 ) ;define
 
+(define (beamer-switch-allowed? empty? dirty? already-beamer?)
+  (or empty? dirty? already-beamer?)
+) ;define
+
+(define (test-beamer-switch-allowed?)
+  ;; Empty documents may always switch to Beamer.
+  (check (beamer-switch-allowed? #t #f #f) => #t)
+  ;; A dirty buffer is allowed to switch back to Beamer without requiring a save.
+  (check (beamer-switch-allowed? #f #t #f) => #t)
+  ;; A document that is already Beamer should not be blocked.
+  (check (beamer-switch-allowed? #f #f #t) => #t)
+  ;; A non-empty, clean, non-Beamer document remains blocked.
+  (check (beamer-switch-allowed? #f #f #f) => #f)
+) ;define
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Test entry point
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-(tm-define (regtest-generic) (test-focus-tag-name) (check-report))
+(tm-define (regtest-generic)
+  (test-focus-tag-name)
+  (test-beamer-switch-allowed?)
+  (check-report)
+) ;tm-define