recursive parse in calc example

1 files changed, 5 insertions, 1 deletions

diff --git a/examples/calc.lisp b/examples/calc.lisp
index 14b03e5..87993e8 100644
--- a/examples/calc.lisp
+++ b/examples/calc.lisp
@@ -7,11 +7,15 @@
 
 (deflanguage calc (:documentation "A calculator language")
   (<calc> :-> (:or
+               (:seq <subexpr> (:eof))
                (:seq <value> (:eof))
                (:seq <unop> (:eof))
                (:seq <binop> (:eof)))
           :=> car)
-  (<expr>  :-> (:or <value> <unop> <binop>))
+  (<expr>  :-> (:or <subexpr> <value> <unop> <binop>))
+  (<subexpr> :-> (:item)
+             :?? listp
+             :=> (argot:parse calc <subexpr> ))
   (<value> :-> (:item) :?? numberp)
   (<binop> :-> (:seq (:@ lhs <expr>)
                      (:@ rhs (:+ (:seq (:or= + - / * ^ %) <expr>))))