refactor(parser): Reduce code duplication

Author: epage

src/parser/arg_matcher.rs

@@ -153,20 +153,11 @@ impl ArgMatcher {
     }
 
     pub(crate) fn start_occurrence_of_arg(&mut self, arg: &Arg) {
-        let id = arg.get_id().clone();
-        debug!("ArgMatcher::start_occurrence_of_arg: id={:?}", id);
-        let ma = self.entry(id).or_insert(MatchedArg::new_arg(arg));
-        debug_assert_eq!(ma.type_id(), Some(arg.get_value_parser().type_id()));
-        ma.set_source(ValueSource::CommandLine);
-        ma.new_val_group();
+        self.start_custom_arg(arg, ValueSource::CommandLine);
     }
 
     pub(crate) fn start_occurrence_of_group(&mut self, id: Id) {
-        debug!("ArgMatcher::start_occurrence_of_group: id={:?}", id);
-        let ma = self.entry(id).or_insert(MatchedArg::new_group());
-        debug_assert_eq!(ma.type_id(), None);
-        ma.set_source(ValueSource::CommandLine);
-        ma.new_val_group();
+        self.start_custom_group(id, ValueSource::CommandLine);
     }
 
     pub(crate) fn start_occurrence_of_external(&mut self, cmd: &crate::Command) {