[llvm] [ADT] Add `isPunct` to StringExtras (PR #105461)

[Sergei Barannikov via llvm-commits]

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@@ -380,3 +382,14 @@ TEST(StringExtrasTest, arrayToStringRef) {
   roundTripTestString("\0\n");
   roundTripTestString("\xFF\xFE");
 }
+
+TEST(StringExtrasTest, isPunct) {
+  // Loop over all valid char values and verify that llvm::isPunct matched
+  // std::ispunct(). Limit to first 256 characters in case CHAR_BIT > 8.
+  int Count = 0;
+  for (char C = std::numeric_limits<char>::min(); Count < 256; ++C) {
+    EXPECT_EQ(static_cast<bool>(std::ispunct(C)), isPunct(C));
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s-barannikov wrote:

> Or just have a curated list of punct and non punct characters?

Maybe just check a few? There are tests at the beginning of this file that test similar interfaces, they don't check all possible values.

I'm not very familiar with locales either, and it is possible that calling `std::ispunct` is totally safe here (or can be made safe by setting C locale).


https://github.com/llvm/llvm-project/pull/105461