2 files changed, 52 insertions, 14 deletions
diff --git a/src/csets.rs b/src/csets.rs
new file mode 100644
index 0000000..ab924dc
--- /dev/null
+++ b/src/csets.rs
@@ -0,0 +1,51 @@
+pub trait CharacterSet {
+	fn contains(ch: char) -> bool;
+}
+
+pub struct AnyCharacter;
+
+impl CharacterSet for AnyCharacter {
+	fn contains(_: char) -> bool {
+		true
+	}
+}
+
+pub struct Ascii;
+
+impl CharacterSet for Ascii {
+	fn contains(ch: char) -> bool {
+		ch.is_ascii()
+	}
+}
+
+pub struct AsciiDigits;
+
+impl CharacterSet for AsciiDigits {
+	fn contains(ch: char) -> bool {
+		ch.is_ascii_digit()
+	}
+}
+
+pub struct AsciiLowercase;
+
+impl CharacterSet for AsciiLowercase {
+	fn contains(ch: char) -> bool {
+		ch.is_ascii_lowercase()
+	}
+}
+
+pub struct AsciiUppercase;
+
+impl CharacterSet for AsciiUppercase {
+	fn contains(ch: char) -> bool {
+		ch.is_ascii_uppercase()
+	}
+}
+
+pub struct AsciiLetters;
+
+impl CharacterSet for AsciiLetters {
+	fn contains(ch: char) -> bool {
+		ch.is_ascii_alphabetic()
+	}
+}
diff --git a/src/lib.rs b/src/lib.rs
index 7d12d9a..00a4d4b 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,14 +1 @@
-pub fn add(left: usize, right: usize) -> usize {
-    left + right
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
-    }
-}
+pub mod csets;