accept newlines after arrows in fn clauses; make some asts mutable for validation

janet/recursive.janet

@@ -701,6 +701,7 @@
    (print "parsed guard")
    (expect parser :arrow) (advance parser)
    (print "parsed arrow")
+   (accept-many parser :newline)
    (def rhs (nonbinding parser))
    (print "parsed rhs")
    [[lhs guard rhs]]
@@ -718,6 +719,7 @@
     (advance parser)
     (simple parser)))
    (expect parser :arrow) (advance parser)
+   (accept-many parser :newline)
    (def rhs (nonbinding parser))
    (terminator parser)
    [lhs guard rhs])
@@ -745,7 +747,7 @@
 (defn- lambda [parser]
  (def origin (current parser))
  (expect parser :fn) (advance parser)
- {:type :fn :data (fn-simple parser) :token origin})
+ @{:type :fn :data (fn-simple parser) :token origin})
 
 (defn- fnn [parser]
  (if (= :lparen (-> parser peek type)) (break (lambda parser)))
@@ -764,7 +766,7 @@
     :lbrace (fn-clauses parser)
     :lparen (fn-simple parser)
     (panic parser (string "expected clause or clauses, got " (-> current parser type)))))
-   {:type :fn :name name :data data :token origin})
+   @{:type :fn :name name :data data :token origin})
   ([err] err)))
 
 ### compoound forms
@@ -864,7 +866,7 @@
    (expect parser :ns) (advance parser)
    (def name (-> parser pkg-name (get :data)))
    (def body (block parser))
-   {:type :ns :data body :name name :token origin})
+   @{:type :ns :data body :name name :token origin})
   ([err] err)))
 
 (defn- importt [parser]
@@ -895,7 +897,7 @@
   :lparen (fn-simple parser)
   :lbrace (fn-clauses parser)
  ))
- {:type :loop :data [args clauses] :token origin})
+ @{:type :loop :data [args clauses] :token origin})
 
 (defn- recur [parser]
  (def origin (current parser))
@@ -1091,7 +1093,7 @@
 (do
 #(comment
 (def source `
-pkg Foo {:bar nil}
+loop (1, 2) with (x, y) -> :bar
 `)
 (def scanned (s/scan source))
 (print "\n***NEW PARSE***\n")