feat(scanner): added IgnoreCaseNormalized comparison marker.

Author: DanielKeep

src/input.rs

@@ -633,6 +633,49 @@ fn test_ignore_case() {
     assert_eq!(IC::compare("ßẞ", "ẞß"), true);
 }
 
+/**
+Marker type used to do case-insensitive, normalized string comparisons.
+
+Specifically, this type will compare strings based on the result of a NFD transform, followed by conversion to lower-case.
+
+Note that this *does not* take any locale information into account.  It is only as correct as a call to `char::to_lowercase`.
+*/
+#[cfg(feature="unicode-normalization")]
+#[derive(Debug)]
+pub enum IgnoreCaseNormalized {}
+
+#[cfg(feature="unicode-normalization")]
+impl StrCompare for IgnoreCaseNormalized {
+    fn compare(a: &str, b: &str) -> bool {
+        use unicode_normalization::UnicodeNormalization;
+
+        let mut acs = a.nfd().flat_map(char::to_lowercase);
+        let mut bcs = b.nfd().flat_map(char::to_lowercase);
+        loop {
+            match (acs.next(), bcs.next()) {
+                (Some(a), Some(b)) if a == b => (),
+                (None, None) => return true,
+                _ => return false
+            }
+        }
+    }
+}
+
+#[cfg(feature="unicode-normalization")]
+#[cfg(test)]
+#[test]
+fn test_ignore_case_normalized() {
+    use self::IgnoreCaseNormalized as ICN;
+
+    assert_eq!(ICN::compare("hi", "hi"), true);
+    assert_eq!(ICN::compare("Hi", "hI"), true);
+    assert_eq!(ICN::compare("hI", "Hi"), true);
+    assert_eq!(ICN::compare("café", "cafe\u{301}"), true);
+    assert_eq!(ICN::compare("cafe\u{301}", "café"), true);
+    assert_eq!(ICN::compare("CafÉ", "CafE\u{301}"), true);
+    assert_eq!(ICN::compare("CAFÉ", "cafe\u{301}"), true);
+}
+
 /**
 Marker type used to do ASCII case-insensitive string comparisons.
 

tests/case_match.rs

@@ -14,6 +14,9 @@ use scan_rules::ScanError as SE;
 use scan_rules::ScanErrorKind as SEK;
 use scan_rules::input::{StrCursor, ExactCompare, IgnoreCase, IgnoreAsciiCase};
 
+#[cfg(feature="unicode-normalization")]
+use scan_rules::input::IgnoreCaseNormalized;
+
 #[test]
 fn test_case_match() {
     let inp = "UPPERCASE lowercase mIxeDcAsE TitleCase";
@@ -109,6 +112,42 @@ fn test_case_match() {
     );
 }
 
+#[cfg(feature="unicode-normalization")]
+#[test]
+fn test_case_match_normalized() {
+    let inp = "UPPERCASE lowercase mIxeDcAsE TitleCase";
+
+    assert_match!(
+        scan!(StrCursor::<IgnoreCaseNormalized>::new(inp);
+            ("UPPERCASE", "lowercase", "mIxeDcAsE", "TitleCase") => ()),
+        Ok(())
+    );
+
+    assert_match!(
+        scan!(StrCursor::<IgnoreCaseNormalized>::new(inp);
+            ("UPPERCaSE", "lowercase", "mIxeDcAsE", "TitleCase") => ()),
+        Ok(())
+    );
+
+    assert_match!(
+        scan!(StrCursor::<IgnoreCaseNormalized>::new(inp);
+            ("UPPERCASE", "lowerCase", "mIxeDcAsE", "TitleCase") => ()),
+        Ok(())
+    );
+
+    assert_match!(
+        scan!(StrCursor::<IgnoreCaseNormalized>::new(inp);
+            ("UPPERCASE", "lowercase", "mIxEdcAsE", "TitleCase") => ()),
+        Ok(())
+    );
+
+    assert_match!(
+        scan!(StrCursor::<IgnoreCaseNormalized>::new(inp);
+            ("UPPERCASE", "lowercase", "mIxeDcAsE", "TitLecAse") => ()),
+        Ok(())
+    );
+}
+
 /**
 Make sure the "official" API style for new code works.
 */