+#--------------------------------------------
+# VTFLAGS: Vertical tightness types and flags
+#--------------------------------------------
+# Vertical tightness is controlled by a 'type' and associated 'flags' for each
+# line. These values are set by sub Formatter::set_vertical_tightness_flags.
+# These are defined as follows:
+
+# Vertical Tightness Line Type Codes:
+# Type 0, no vertical tightness condition
+# Type 1, last token of this line is a non-block opening token
+# Type 2, first token of next line is a non-block closing
+# Type 3, isolated opening block brace
+# type 4, isolated closing block brace
+
+# Opening token flag values are the vertical tightness flags
+# 0 do not join with next line
+# 1 just one join per line
+# 2 any number of joins
+
+# Closing token flag values indicate spacing:
+# 0 = no space added before closing token
+# 1 = single space added before closing token
+