* Added yang access functions

* Change all y->ys_parent to yang_parent_get(y)
    * Change all y->ys_keyword to yang_keyword_get(y)
    * Change all y->ys_argument to yang_argument_get(y)
    * Change all y->ys_cv to yang_cv_get(y)
    * Change all y->ys_cvec to yang_cvec_get(y)

lib/src/clixon_xml.c

@@ -625,6 +625,7 @@ xml_child_i_set(cxobj *xt,
  *     ...
  *   }
  * @endcode
+ * @note makes uses _x_vector_i:can be changed if list changed between calls
  */
 cxobj *
 xml_child_each(cxobj           *xparent, 
@@ -791,7 +792,7 @@ xml_cv_set(cxobj  *x,
  *
  * @retval xmlobj     if found.
  * @retval NULL       if no such node found.
- * @see xml_find_type  which is a more generic function
+ * @see xml_find_type  A more generic function
  */
 cxobj *
 xml_find(cxobj *x_up, 

lib/src/clixon_yang.c

@@ -87,9 +87,9 @@
 #include "clixon_plugin.h"
 #include "clixon_data.h"
 #include "clixon_options.h"
-#include "clixon_yang_type.h"
 #include "clixon_yang_parse.h"
 #include "clixon_yang_cardinality.h"
+#include "clixon_yang_type.h"
 
 /* Size of json read buffer when reading from file*/
 #define BUFLEN 1024
@@ -174,6 +174,56 @@ static const map_str2int ykmap[] = {
     {NULL,               -1}
 };
 
+/* Access functions
+ */
+
+/*! Get yang statement parent
+ * @param[in] ys  Yang statement node
+ */
+yang_stmt *
+yang_parent_get(yang_stmt *ys)
+{
+    return ys->ys_parent;
+}
+
+/*! Get yang statement keyword
+ * @param[in] ys  Yang statement node
+ */
+enum rfc_6020
+yang_keyword_get(yang_stmt *ys)
+{
+    return ys->ys_keyword;
+}
+
+/*! Get yang statement context-dependent argument
+ * @param[in] ys  Yang statement node
+ */
+char*
+yang_argument_get(yang_stmt *ys)
+{
+    return ys->ys_argument;
+}
+
+/*! Get yang statement CLIgen variable
+ * @param[in] ys  Yang statement node
+ */
+cg_var*
+yang_cv_get(yang_stmt *ys)
+{
+    return ys->ys_cv;
+}
+
+/*! Get yang statement CLIgen variable vector
+ * @param[in] ys  Yang statement node
+ */
+cvec*
+yang_cvec_get(yang_stmt *ys)
+{
+    return ys->ys_cvec;
+}
+
+/* End access functions */
+
 /*! Create new yang specification
  * @retval  yspec    Free with yspec_free() 
  * @retval  NULL     Error
@@ -392,29 +442,38 @@ yn_insert(yang_stmt *ys_parent,
 
 /*! Iterate through all yang statements from a yang node 
  *
- * Note that this is not optimized, one could use 'i' as index?
+ * @param[in] yparent  yang statement whose children should be iterated
+ * @param[in] yprev    previous child, or NULL on init
  * @code
- *   yang_stmt *ys = NULL;
- *   while ((ys = yn_each(yn, ys)) != NULL) {
- *     ...ys...
+ *   yang_stmt *yprev = NULL;
+ *   while ((yprev = yn_each(yparent, yprev)) != NULL) {
+ *     ...yprev...
  *   }
  * @endcode
+ * @note makes uses _ys_vector_i:can be changed if list changed between calls
  */
 yang_stmt *
-yn_each(yang_stmt *yn, 
-	yang_stmt *ys)
+yn_each(yang_stmt *yparent, 
+	yang_stmt *yprev)
 {
+    int        i;
     yang_stmt *yc = NULL;
-    int i;
 
-    for (i=0; i<yn->ys_len; i++){
-	yc = yn->ys_stmt[i];
-	if (ys==NULL)
-	    return yc;
-	if (ys==yc)
-	    ys = NULL;
+    if (yparent == NULL)
+	return NULL;
+    for (i=yprev?yprev->_ys_vector_i+1:0; i<yparent->ys_len; i++){
+	if ((yc = yparent->ys_stmt[i]) == NULL){
+	    assert(yc); /* XXX Check if happens */
+	    continue;
+	}
+	/* make room for other conditionals */
+	break; /* this is next object after previous */
     }
-    return NULL;
+    if (i < yparent->ys_len) /* found */
+	yc->_ys_vector_i = i;
+    else
+	yc = NULL;
+    return yc;
 }
 
 /*! Find first child yang_stmt with matching keyword and argument

lib/src/clixon_yang_internal.h

@@ -0,0 +1,91 @@
+/*
+ *
+  ***** BEGIN LICENSE BLOCK *****
+ 
+  Copyright (C) 2009-2019 Olof Hagsand and Benny Holmgren
+
+  This file is part of CLIXON.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+  Alternatively, the contents of this file may be used under the terms of
+  the GNU General Public License Version 3 or later (the "GPL"),
+  in which case the provisions of the GPL are applicable instead
+  of those above. If you wish to allow use of your version of this file only
+  under the terms of the GPL, and not to allow others to
+  use your version of this file under the terms of Apache License version 2, 
+  indicate your decision by deleting the provisions above and replace them with
+  the  notice and other provisions required by the GPL. If you do not delete
+  the provisions above, a recipient may use your version of this file under
+  the terms of any one of the Apache License version 2 or the GPL.
+
+  ***** END LICENSE BLOCK *****
+
+ * Yang functions
+ * @see https://tools.ietf.org/html/rfc6020 YANG 1.0
+ * @see https://tools.ietf.org/html/rfc7950 YANG 1.1
+ */
+
+#ifndef _CLIXON_YANG_INTERNAL_H_
+#define _CLIXON_YANG_INTERNAL_H_
+
+/*! Yang type cache. Yang type statements can cache all typedef info here
+ * @note unions not cached
+*/
+struct yang_type_cache{
+    int        yc_options;  /* See YANG_OPTIONS_* that determines pattern/
+			       fraction fields. */
+    cvec      *yc_cvv;      /* Range and length restriction. (if YANG_OPTION_
+                               LENGTH|RANGE. Can be a vector if multiple 
+                               ranges*/
+    char      *yc_pattern;  /* regex (posix) (if YANG_OPTIONS_PATTERN) */
+    uint8_t    yc_fraction; /* Fraction digits for decimal64 (if 
+                               YANG_OPTIONS_FRACTION_DIGITS */
+    yang_stmt *yc_resolved; /* Resolved type object, can be NULL - note direct ptr */
+};
+typedef struct yang_type_cache yang_type_cache;
+
+/*! yang statement 
+ */
+struct yang_stmt{
+    int                ys_len;       /* Number of children */
+    struct yang_stmt **ys_stmt;      /* Vector of children statement pointers */
+    struct yang_stmt  *ys_parent;    /* Backpointer to parent: yang-stmt or yang-spec */
+    enum rfc_6020      ys_keyword;   /* See clicon_yang_parse.tab.h */
+
+    char              *ys_argument;  /* String / argument depending on keyword */   
+    int                ys_flags;     /* Flags according to YANG_FLAG_* above */
+    yang_stmt         *ys_module;   /* Shortcut to "my" module. Augmented
+				       nodes can belong to other 
+					modules than the ancestor module */
+
+    char              *ys_extra;     /* For unknown */
+    cg_var            *ys_cv;        /* cligen variable. See ys_populate()
+					Following stmts have cv:s:
+				        leaf: for default value
+					leaf-list, 
+					config: boolean true or false
+					mandatory: boolean true or false
+					fraction-digits for fraction-digits
+					unknown-stmt (argument)
+				     */
+    cvec              *ys_cvec;      /* List of stmt-specific variables 
+					Y_RANGE: range_min, range_max 
+					Y_LIST: vector of keys
+					Y_TYPE & identity: store all derived types
+				     */
+    yang_type_cache   *ys_typecache; /* If ys_keyword==Y_TYPE, cache all typedef data except unions */
+    int               _ys_vector_i;   /* internal use: yn_each */
+};
+
+#endif  /* _CLIXON_YANG_INTERNAL_H_ */