if expressions, done

janet/recursive.janet

@@ -48,7 +48,8 @@
  (= type current-type))
 
 ### Parsing functions
-(declare nonbinding binding synthetic)
+# forward declarations
+(declare simple nonbinding expr toplevel synthetic)
 
 # errors
 (def terminators [:break :newline :semicolon :eof])
@@ -66,7 +67,7 @@
  (has-value? breaking ttype))
 
 (defn- panic [parser message]
- # (print "Panic in the parser: " message)
+ (print "Panic in the parser: " message)
  (def origin (current parser))
  (advance parser)
  (def skipped @[origin])
@@ -74,7 +75,6 @@
   (array/push skipped (current parser))
   (advance parser))
  (array/push skipped (current parser))
- # (advance parser)
  (def err {:type :error :data skipped :token origin :msg message})
  (update parser :errors array/push err)
  (error err))
@@ -88,6 +88,9 @@
 (defn- expect-ret [parser type]
  (try (expect parser type) ([e] e)))
 
+(defn- capture [parse-fn parser]
+ (try (parse-fn parser) ([e] e)))
+
 # atoms
 (defn- bool [parser]
  (expect parser :bool)
@@ -223,7 +226,7 @@
  (advance parser)
  ast)
 
-(defn- set [parser]
+(defn- sett [parser]
  (def origin (current parser))
  (advance parser)
  (def ast {:type :set :data @[] :token origin})
@@ -268,11 +271,13 @@
 (defn- iff [parser]
  (def ast {:type :if :data @[] :token (current parser)})
  (advance parser) #consume the if
- (update ast array/push :data (simple parser))
+ (array/push (ast :data) (capture simple parser))
- (when-let [err (expect-ret parser :then)] (update ast array/push :data err))
+ (when-let [err (expect-ret parser :then)] (array/push (ast :data) err))
- (update ast array/push :data (nonbinding parser))
+ (advance parser)
- (when-let [err (expect-ret parser :else)] (update ast array/push :data err))
+ (array/push (ast :data) (capture nonbinding parser))
- (update ast array/push :data (nonbinding parser))
+ (when-let [err (expect-ret parser :else)] (array/push (ast :data) err))
+ (advance parser)
+ (array/push (ast :data) (capture nonbinding parser))
  ast)
 
 (defn- condd [parser])
@@ -377,7 +382,7 @@
   :startdict (dict parser)
   :startset (sett parser)
   :word (word parser)
-  :if (unreachable)
+  :if (iff parser)
   :cond (unreachable)
   :match (unreachable)
   :with (unreachable)
@@ -409,7 +414,7 @@
   :startdict (dict parser)
   :startset (sett parser)
   :word (word parser)
-  :if (unreachable)
+  :if (iff parser)
   :cond (unreachable)
   :match (unreachable)
   :with (unreachable)
@@ -423,8 +428,8 @@
 (import ./scanner :as s)
 (do
 #(comment
-
+(def source "if foo then else baz")
-(def scanned (s/scan "#{}"))
+(def scanned (s/scan source))
 (def a-parser (new-parser scanned))
 (def parsed (nonbinding a-parser))
 (-> parsed)