fix the syntax in example -- use pure () instead of =>

docs/grammar/cicada.grammar

@@ -1,68 +1,29 @@
 (define-grammar <operator>
-  (var (let name identifier))
-  (ap (let target operator)
-      (let arg-entries-group (one-or-more "(" arg-entries ")")))
-  (sequence-begin (let sequence sequence))
-  (car "car" "(" (let target exp) ")")
-  (cdr "cdr" "(" (let target exp) ")")
-  (dot-field (let target operator) "." (let name identifier))
-  (dot-method
-   (let target operator) "." (let name identifier)
-   (let arg-entries-group (one-or-more "(" arg-entries ")")))
-  (recursion
-   "recursion" "(" (let target exp) ")"
-   "{" (let case-entries (zero-or-more case-entry)) "}")
-  (induction
-   "induction" "(" (let target exp) ")"
-   "{" "motive" (let motive "exp")
-   (let case-entries (zero-or-more case-entry)) "}"))
-
-(define-grammar <operator>
-  [var (let name <identifier>) => (Exp::Var (match-string name))]
-  [ap (let target <operator>)
-      (let arg-entries-group (one-or-more "(" <arg-entries> ")"))
-   => (Exp::Ap (match <exp> target)
-               (match-list ...))]
-  [sequence-begin (let sequence <sequence>)
-   => (Exp::Sequence (match <sequence> sequence))]
-  [car "car" "(" (let target <exp>) ")"
-   => (Exp::Car (match <exp> target))]
-  [cdr "cdr" "(" (let target <exp>) ")"
-   => (Exp::Cdr (match <exp> target))]
-  [dot-field (let target <operator>) "." (let name <identifier>)
-   => (Exp::Dot (match <exp> target) (match <identifier> name))]
-  [dot-method
-   (let target <operator>) "." (let name <identifier>)
-   (let arg-entries-group (one-or-more "(" <arg-entries> ")"))]
-  [recursion
-   "recursion" "(" (let target <exp>) ")"
-   "{" (let case-entries (zero-or-more <case-entry>)) "}"]
-  [induction
-   "induction" "(" (let target exp) ")"
-   "{" "motive" (let motive "exp")
-   (let case-entries (zero-or-more <case-entry>)) "}"])
-
-(define-grammar <operator>
-  [var (let name <identifier>) => (Exp::Var name)]
-  [ap (let target <operator>)
-      (let arg-entries-group (one-or-more "(" <arg-entries> ")"))
-   => (Exp::Ap target
-               (TODO arg-entries-group))]
-  [sequence-begin (let sequence <sequence>)
-   => (Exp::Sequence sequence)]
-  [car "car" "(" (let target <exp>) ")"
-   => (Exp::Car target)]
-  [cdr "cdr" "(" (let target <exp>) ")"
-   => (Exp::Cdr target)]
-  [dot-field (let target <operator>) "." (let name <identifier>)
-   => (Exp::Dot target name)]
-  [dot-method
-   (let target <operator>) "." (let name <identifier>)
-   (let arg-entries-group (one-or-more "(" <arg-entries> ")"))]
-  [recursion
-   "recursion" "(" (let target <exp>) ")"
-   "{" (let case-entries (zero-or-more <case-entry>)) "}"]
-  [induction
-   "induction" "(" (let target exp) ")"
-   "{" "motive" (let motive "exp")
-   (let case-entries (zero-or-more <case-entry>)) "}"])
+  ((<operator::var> (let name <identifier>))
+   (Exp::Var name))
+  ((<operator::ap>
+    (let target <operator>)
+    (let arg-entries-group (one-or-more "(" <arg-entries> ")")))
+   (Exp::ApUnfolded target (flatten arg-entries-group)))
+  ((<operator::sequence-begin> (let sequence <sequence>))
+   (Exp::Sequence sequence))
+  ((<operator::car> "car" "(" (let target <exp>) ")")
+   (Exp::Car target))
+  ((<operator::cdr> "cdr" "(" (let target <exp>) ")")
+   (Exp::Cdr target))
+  ((<operator::dot-field>
+    (let target <operator>) "." (let name <identifier>))
+   (Exp::Dot target name))
+  ((<operator::dot-method>
+    (let target <operator>) "." (let name <identifier>)
+    (let arg-entries-group (one-or-more "(" <arg-entries> ")")))
+   (Exp::ApUnfolded (Exp::Dot target name) (flatten arg-entries-group)))
+  ((<operator::recursion>
+    "recursion" "(" (let target <exp>) ")"
+    "{" (let case-entries (zero-or-more <case-entry>)) "}")
+   (Exp::Recursion target case-entries))
+  ((<operator::induction>
+    "induction" "(" (let target <exp>) ")"
+    "{" "motive" (let motive <exp>)
+    (let case-entries (zero-or-more <case-entry>)) "}")
+   (Exp::Induction target motive case-entries)))