Support translated YANG models.

This change allows one model to be translated to another model. This is
useful if multiple YANG models for the same type of data exist. In this
case a back-end super YANG model is created which is a combination of
the contributing models, and requests to the individual models are
translated into a request of the super model and responses are
translated back into the individual requesting models. In the Apteryx
data store information only exists for the super model. The translation
is controlled by a translating configuration file named {name}.xlat

is that a single super mode

apteryx-xml.h

@@ -93,6 +93,9 @@ char *sch_translate_from (sch_node * node, char *value);
 bool sch_validate_pattern (sch_node * node, const char *value);
 gboolean sch_match_name (const char *s1, const char *s2);
 bool sch_ns_match (sch_node *node, void *ns);
+GNode *sch_translate_input (sch_instance * instance, GNode *node, int flags,
+                            void **xlat_data, sch_node **rschema);
+GNode *sch_translate_output (sch_instance * instance, GNode *node, int flags, void *xlat_data);
 
 /* Data translation/manipulation */
 typedef enum

models/xlat_test.lua

@@ -0,0 +1,29 @@
+xlat_data = {}
+
+xlat_data.translate_type = function(field, value, dir)
+    local value1 = value
+    if field == 'type' then
+        value1 = tonumber (value)
+        print("field " .. field)
+        print("value1 " .. value1)
+        print("dir " .. dir)
+        if dir == 'out' then
+            if value == '1' then
+                value1 = '3'
+            else
+                value1 = '4'
+            end
+            print("value1 " .. value1)
+        else
+            if value == '3' then
+                value1 = '1'
+            else
+                value1 = '2'
+            end
+        end
+    end
+    return value1
+end
+
+return xlat_data
+

models/xlat_test.xlat

@@ -0,0 +1,7 @@
+/xlat-test/xlat-animals /test/animals/animal
+/xlat-test/xlat-animals/xlat-animal /test/animals/animal
+/xlat-test/xlat-animals/xlat-animal/*/name /test/animals/animal/*/name
+/xlat-test/xlat-animals/xlat-animal/*/type /test/animals/animal/*/type xlat_data.translate_type
+/xlat-test/xlat-animals/xlat-animal/*/colour /test/animals/animal/*/colour
+/xlat-test/xlat-animals/xlat-animal/*/food /test/animals/animal/*/food
+/xlat-test/xlat-animals/xlat-animal/*/toys /test/animals/animal/*/toys

models/xlat_test.xml

@@ -0,0 +1,32 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<MODULE xmlns="http://test.com/ns/yang/xlat-testing"
+    xmlns:xlat-test="http://test.com/ns/yang/xlat-testing"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="https://github.com/alliedtelesis/apteryx-xml https://github.com/alliedtelesis/apteryx-xml/releases/download/v1.2/apteryx.xsd"
+    model="xlat-test" organization="Test Ltd" version="2023-01-01">
+    <NODE name="xlat-test" help="This is a test node">
+        <NODE name="xlat-animals">
+            <NODE name="xlat-animal" help="This is a list of animals">
+                <NODE name="*" help="The animal entry with key name">
+                    <NODE name="name" mode="rw" help="This is the name of the animal" />
+                    <NODE name="type" mode="rw" default="big" help="This is the type of the animal">
+                        <VALUE name="fast" value="3" />
+                        <VALUE name="slow" value="4" />
+                    </NODE>
+                    <NODE name="colour" mode="rw" help="This is the colour of the animal" />
+                    <NODE name="food">
+                        <NODE name="*" help="This is a list of food">
+                            <NODE name="name" mode="rw" help="Food name" />
+                            <NODE name="type" mode="rw" help="Food type" />
+                        </NODE>
+                    </NODE>
+                    <NODE name="toys">
+                        <NODE name="toy" help="This is a leaf list of toys">
+                            <NODE name="*" mode="rw" help="List of toys" />
+                        </NODE>
+                    </NODE>
+                </NODE>
+            </NODE>
+        </NODE>
+    </NODE>
+</MODULE>