From b8d293940be7a59f7ffbe8cd31fce54a3b3bd212 Mon Sep 17 00:00:00 2001
From: "Eric S. Raymond" <esr@thyrsus.com>
Date: Fri, 11 Nov 1994 21:43:23 +0000
Subject: [PATCH] Initial revision

---
 nodetype.h | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 nodetype.h

diff --git a/nodetype.h b/nodetype.h
new file mode 100644
index 0000000..17f967b
--- /dev/null
+++ b/nodetype.h
@@ -0,0 +1,27 @@
+/* nodetype.h -- macros that describe the semantics of nodes */
+
+#define car	u.n.left
+#define cdr	u.n.right
+
+/*
+ * Define token classes for consistency checks here.  The theory is
+ * that by separating this from the tree-traversal machinery below, we
+ * may be able to parametrize for different source languages someday.
+ */
+/* does the node represent an atom? */
+#define ATOMIC(n)	((n) == IDENTIFIER || (n) == NUMBER || (n) == STRING)
+/* does the node reference a statement label? */
+#define SLABELREF(n)	((n) == GO || (n) == OG)
+/* does the node reference a block label? */
+#define BLABELREF(n)	((n) == PERFORM)
+/* does the node set a variable? */
+#define VARSET(n)	((n) == LET || (n) == READ || (n) == ITERATE)
+/* does the (non-VARSET) node refer to its left operand as a variable? */ 
+#define LEFTREF(n)	((n) != FOR && (n) != GO && (n) != OG && (n) != LABEL \
+				&& (n) != ALLOCATE && (n) != WATCH \
+				&& (n) != ITERATE && (n) != FROM \
+		     		&& (n) != PERFORM)
+/* does the (non-VARSET) node refer to its right operand? */
+#define RIGHTREF(n)	((n) != PERFORM)
+
+/* nodetype.h ends here */
-- 
2.43.0