lexer: Fun little lexer hack to allow trailing commas

src/lexer.rs

@@ -123,7 +123,7 @@ impl<'t> Lexer<'t> {
             ')' => RParen,
             '*' => Star,
             '+' => Plus,
-            ',' => Comma,
+            ',' => return self.consume().trailing(Comma),
             '-' => Minus,
             '.' => Dot,
             '/' => Slash,
@@ -198,6 +198,15 @@ impl<'t> Lexer<'t> {
         Ok(self.consume().produce(tok))
     }
 
+    pub fn trailing(&mut self, kind: TKind) -> Result<Token, LexError> {
+        Ok(match self.skip_whitespace().peek() {
+            // Some(')') => self.consume().produce(TKind::RParen), // maybe.
+            Some(']') => self.consume().produce(TKind::RBrack),
+            Some('}') => self.consume().produce(TKind::RCurly),
+            _ => self.produce(kind),
+        })
+    }
+
     pub fn line_comment(&mut self) -> Result<Token, LexError> {
         while self.consume().peek().is_some_and(|c| c != '\n') {}
         Ok(self.produce(TKind::Comment))