Index: trunk/Ohana/src/libautocode/doc/autocode.txt
===================================================================
--- trunk/Ohana/src/libautocode/doc/autocode.txt	(revision 21508)
+++ trunk/Ohana/src/libautocode/doc/autocode.txt	(revision 37807)
@@ -35,7 +35,20 @@
 
 - the element name
+- the element FITS field (in FITS table)
 - the element data type
 - the element description
 - the element physical unit
+
+SUBFIELD / SUBSTRUCT keywords allows the user to define elements of a
+structure which are themselves structures.  These fields are used as
+follow:
+
+Binary / ASCII FITS tables write out the SUBFIELD entries as if they
+were regular table rows (substructure distinction not visible in FITS
+table).  SUBSTRUCT rows are NOT added to the FITS table.
+
+In a C-structure, the SUBFIELD rows are skipped and only the SUBSTRUCT
+row is saved.  The definition of the substructure is assumed to be
+defined elsewhere in the C code.
 
 Template File
@@ -43,11 +56,13 @@
 The template file is a source code in whatever language is desired.
 Within the template, the defined keywords may be used as desired,
-wherever needed.  In addition, there are special directives which
-invoke additional special behavior.  All special directives have the
-form of comments within their target language.  They are replaced with
-a block of code in that target language, normally one which iterates
-over the FIELD elements of the schema file.  As such, the directive
-appropriate for one language should not be used within code for a
-different language.  Here is a list of existing special directives:
+wherever needed.  
+
+In addition, there are special directives which invoke additional
+special behavior.  All special directives have the form of comments
+within their target language.  They are replaced with a block of code
+in that target language, normally one which iterates over the FIELD
+elements of the schema file.  As such, the directive appropriate for
+one language should not be used within code for a different language.
+Here is a list of existing special directives:
 
 /** STRUCT DEFINITION **/