internal: string parser with chumsky

src/lib.rs

@@ -481,3 +481,44 @@ trait ChumskyParser<O>: chumsky::Parser<char, O, Error = ChumskyError> {}
 
 #[cfg(test)]
 impl<O, P: chumsky::Parser<char, O, Error = ChumskyError>> ChumskyParser<O> for P {}
+
+#[cfg(test)]
+mod chumksy {
+    use chumsky::prelude::*;
+
+    use crate::ChumskyParser;
+
+    fn string() -> impl ChumskyParser<String> {
+        choice((just("\\\"").to('"'), just("\\\\").to('\\'), just('"').not()))
+            .repeated()
+            .delimited_by(just('"'), just('"'))
+            .collect()
+            .labelled("string")
+    }
+
+    #[cfg(test)]
+    mod tests {
+        use super::*;
+        use rstest::rstest;
+
+        #[rstest]
+        #[case::empty("\"\"", "")]
+        #[case::normal("\"hello\"", "hello")]
+        #[case::escaped_quote("\"hello \\\"world\\\"\"", "hello \"world\"")]
+        #[case::escaped_backslash("\"hello\\\\world\"", "hello\\world")]
+        fn should_parse_valid_string(#[case] input: &str, #[case] expected: &str) {
+            let string: String = string().then_ignore(end()).parse(input).unwrap();
+            assert_eq!(string, expected);
+        }
+
+        #[rstest]
+        #[case::nothing("")]
+        #[case::not_quoted("hello")]
+        #[case::not_closed("\"hello")]
+        #[case::not_closed_escaped("\"hello\\\"")]
+        fn should_not_parse_invalid_string(#[case] input: &str) {
+            let result: Result<String, _> = string().then_ignore(end()).parse(input);
+            assert!(result.is_err(), "{result:?}");
+        }
+    }
+}