Use NODE_CASE2 if case expressions don't exist

When NODE_WHEN is compiled by iseq_compile_each0,
the node passed to compile_when is NODE_WHEN (not NODE_CASE).
So we can not handle the location of NODE_CASE of
case statements which don't have case expressions.

e.g. :

```
case; when 1; foo; when 2; bar; else baz; end
```

This commit adds NODE_CASE2, and compiles it by
iseq_compile_each0.

* compile.c (compile_case): Does not call COMPILE_ when
  NODE_CASE does not have case expressions.
* compile.c (compile_case2): Compile NODE_CASE2 by compile_case2.
* compile.c (compile_when): Delete an obsoleted function.
* compile.c (iseq_compile_each0): Compile NODE_CASE2.

* ext/objspace/objspace.c (count_nodes): Add NODE_CASE2 case.

* node.c (dump_node, rb_gc_mark_node): Add NODE_CASE2 case.

* node.h (node_type): Add NODE_CASE2.
* node.h (NEW_CASE2): Add a macro which generates NODE_CASE2.

* parse.y: Generate NODE_CASE2 if case expressions don't exist.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60585 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 9 insertions, 0 deletions

diff --git a/node.c b/node.c
index c671884094..d64b6d282f 100644
--- a/node.c
+++ b/node.c
@@ -219,6 +219,14 @@ dump_node(VALUE buf, VALUE indent, int comment, NODE *node)
 	LAST_NODE;
 	F_NODE(nd_body, "when clauses");
 	return;
+      case NODE_CASE2:
+	ANN("case statement");
+	ANN("format: case; [nd_body]; end");
+	ANN("example: case; when 1; foo; when 2; bar; else baz; end");
+	F_NODE(nd_head, "case expr");
+	LAST_NODE;
+	F_NODE(nd_body, "when clauses");
+	return;
 
       case NODE_WHEN:
 	ANN("if statement");
@@ -1125,6 +1133,7 @@ rb_gc_mark_node(NODE *obj)
       case NODE_AND:
       case NODE_OR:
       case NODE_CASE:
+      case NODE_CASE2:
       case NODE_SCLASS:
       case NODE_DOT2:
       case NODE_DOT3: