Soften restrictions for external parameters (#1277)

* Soften restrictions for external parameters

* Add test

crates/nu-parser/src/parse/parser.rs

@@ -1008,8 +1008,7 @@ fn is_boundary(c: Option<char>) -> bool {
 
 fn is_external_word_char(c: char) -> bool {
     match c {
-        ';' | '|' | '#' | '-' | '"' | '\'' | '$' | '(' | ')' | '[' | ']' | '{' | '}' | '`'
+        ';' | '|' | '"' | '\'' | '$' | '(' | ')' | '[' | ']' | '{' | '}' | '`' => false,
-        | '.' => false,
         other if other.is_whitespace() => false,
         _ => true,
     }

tests/shell/pipeline/commands/external.rs

@@ -78,6 +78,19 @@ mod it_evaluation {
     }
 }
 
+mod external_words {
+    use super::nu;
+
+    #[test]
+    fn relaxed_external_words() {
+        let actual = nu!(cwd: ".", r#"
+        cococo joturner@foo.bar.baz
+        "#);
+
+        assert_eq!(actual, "joturner@foo.bar.baz");
+    }
+}
+
 mod tilde_expansion {
     use super::nu;