Introduce endless range [Feature#12912]

Typical usages:
```
p ary[1..]          # drop the first element; identical to ary[1..-1]
(1..).each {|n|...} # iterate forever from 1; identical to 1.step{...}
```

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63192 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 16 insertions, 0 deletions

diff --git a/parse.y b/parse.y
index 655cd85031..5820e7f73d 100644
--- a/parse.y
+++ b/parse.y
@@ -1903,6 +1903,22 @@ arg		: lhs '=' arg_rhs
 		    /*% %*/
 		    /*% ripper: dot3!($1, $3) %*/
 		    }
+		| arg tDOT2
+		    {
+		    /*%%%*/
+			value_expr($1);
+			$$ = NEW_DOT2($1, new_nil(&@$), &@$);
+		    /*% %*/
+		    /*% ripper: dot2!($1, Qnil) %*/
+		    }
+		| arg tDOT3
+		    {
+		    /*%%%*/
+			value_expr($1);
+			$$ = NEW_DOT3($1, new_nil(&@$), &@$);
+		    /*% %*/
+		    /*% ripper: dot3!($1, Qnil) %*/
+		    }
 		| arg '+' arg
 		    {
 			$$ = call_bin_op(p, $1, '+', $3, &@2, &@$);