From 7471848ef2ee242600749342e66867cb6ef83576 Mon Sep 17 00:00:00 2001
From: CJ van den Berg <cj@vdbonline.com>
Date: Sun, 15 Feb 2026 21:51:38 +0100
Subject: [PATCH] fix: switch_case does nothing if there are non-cased chars in
 range

---
 build.zig.zon          |  4 ++--
 src/buffer/unicode.zig | 27 ++++++++++++++++++++++-----
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/build.zig.zon b/build.zig.zon
index 77dbd65..60a5116 100644
--- a/build.zig.zon
+++ b/build.zig.zon
@@ -30,8 +30,8 @@
             .hash = "fuzzig-0.1.1-Ji0xivxIAQBD0g8O_NV_0foqoPf3elsg9Sc3pNfdVH4D",
         },
         .vaxis = .{
-            .url = "git+https://github.com/neurocyte/libvaxis?ref=main#95034c7114601178467b42e69588cdd4c1d39eb1",
-            .hash = "vaxis-0.5.1-BWNV_PJJCQArtOy_n76jGWoqoBpnM5FKElA_i1IaYYcF",
+            .url = "git+https://github.com/neurocyte/libvaxis?ref=main#4fc5a651a85574c3dfdddebc1d9038fd6bb4e067",
+            .hash = "vaxis-0.5.1-BWNV_EBKCQDqoQZvUE22SBMKYTlZtIIEdLx2X8CfRDHf",
         },
         .zeit = .{
             .url = "git+https://github.com/rockorager/zeit?ref=zig-0.15#ed2ca60db118414bda2b12df2039e33bad3b0b88",
diff --git a/src/buffer/unicode.zig b/src/buffer/unicode.zig
index 4346f84..e329707 100644
--- a/src/buffer/unicode.zig
+++ b/src/buffer/unicode.zig
@@ -150,12 +150,14 @@ fn utf8_transform(comptime field: uucode.FieldEnum, allocator: std.mem.Allocator
     return result.toOwnedSlice();
 }
 
-fn utf8_predicate(comptime field: uucode.FieldEnum, text: []const u8) bool {
+fn utf8_predicate_all(comptime field: uucode.FieldEnum, text: []const u8) bool {
     const view: Utf8View = .initUnchecked(text);
     var it = view.iterator();
     while (it.nextCodepoint()) |cp| {
         const result = switch (field) {
             .is_lowercase => uucode.get(field, cp),
+            .changes_when_casefolded => uucode.get(field, cp),
+            .changes_when_lowercased => uucode.get(field, cp),
             else => @compileError(@tagName(field) ++ " is not a unicode predicate"),
         };
         if (!result) return false;
@@ -163,6 +165,21 @@ fn utf8_predicate(comptime field: uucode.FieldEnum, text: []const u8) bool {
     return true;
 }
 
+fn utf8_predicate_any(comptime field: uucode.FieldEnum, text: []const u8) bool {
+    const view: Utf8View = .initUnchecked(text);
+    var it = view.iterator();
+    while (it.nextCodepoint()) |cp| {
+        const result = switch (field) {
+            .is_lowercase => uucode.get(field, cp),
+            .changes_when_casefolded => uucode.get(field, cp),
+            .changes_when_lowercased => uucode.get(field, cp),
+            else => @compileError(@tagName(field) ++ " is not a unicode predicate"),
+        };
+        if (result) return true;
+    }
+    return false;
+}
+
 pub fn to_upper(allocator: std.mem.Allocator, text: []const u8) TransformError![]u8 {
     return utf8_transform(.simple_uppercase_mapping, allocator, text);
 }
@@ -184,14 +201,14 @@ pub fn case_folded_write_partial(writer: *std.Io.Writer, text: []const u8) Trans
 }
 
 pub fn switch_case(allocator: std.mem.Allocator, text: []const u8) TransformError![]u8 {
-    return if (utf8_predicate(.is_lowercase, text))
-        to_upper(allocator, text)
+    return if (utf8_predicate_any(.changes_when_lowercased, text))
+        to_lower(allocator, text)
     else
-        to_lower(allocator, text);
+        to_upper(allocator, text);
 }
 
 pub fn is_lowercase(text: []const u8) bool {
-    return utf8_predicate(.is_lowercase, text);
+    return utf8_predicate_all(.is_lowercase, text);
 }
 
 const std = @import("std");