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+
+#
+# Regular Definitions
+#
+rl rl_ws /[ \t\n\r\v]+/
+rl rl_id /[a-zA-Z_][a-zA-Z0-9_]*/
+rl rl_num /[0-9]+/
+
+#
+# Tokens
+#
+
+lex start
+{
+ # Ignore whitespace.
+ ignore /rl_ws/
+
+ # Tokens.
+ token id /rl_id/
+ token number /rl_num/
+}
+
+#
+# Global Data
+#
+
+global int target
+
+#
+# Productions
+#
+
+
+def get_target
+ [number]
+ {
+ match lhs [Number:number]
+ target = Number.data.atoi()
+ }
+
+# Arbitrary item.
+def item
+ [number]
+| [id]
+
+# Type definition for the count_items nonterminal.
+def count_items
+ int count
+
+ # List production one. The condition stops the
+ # greedy list when it has gone too far.
+ [count_items item]
+ {
+ # Pass up the data
+ lhs.count = r1.count + 1
+ if lhs.count > target {
+ reject
+ }
+ }
+
+ # List production two, the base.
+| []
+ {
+ lhs.count = 0
+ }
+
+# Wrapper which prevents short lists from getting through if the parser
+# encounters an error and needs to backtrack over counted list.
+def counted_list
+ [get_target count_items]
+ {
+ if r2.count < target {
+ reject
+ }
+ }
+
+
+def start
+ [counted_list*]
+ {
+ for List:counted_list in lhs {
+ match List [Count:number Items:count_items]
+ print( 'num items: ', Count.data.atoi(), '\n' )
+
+ int i = 1
+ for Item:item in Items {
+ print( ' item ', i, ': ', Item, '\n' )
+ i = i + 1
+ }
+ }
+ }