schema: add fraction_digits support

This patch introduces fraction_digits() and all_fraction_digits()
functions for SLeaf and SLeafList.

Fixes: #86
Signed-off-by: Stefan Gula <steweg@gmail.com>
Signed-off-by: Samuel Gauthier <samuel.gauthier@6wind.com>

Author: steweg

libyang/schema.py

@@ -622,6 +622,22 @@ def all_ranges(self) -> Iterator[str]:
             if rng is not None:
                 yield rng
 
+    def fraction_digits(self) -> Optional[int]:
+        if not self.cdata_parsed:
+            return None
+        if self.cdata.basetype != self.DEC64:
+            return None
+        return self.cdata_parsed.fraction_digits
+
+    def all_fraction_digits(self) -> Iterator[int]:
+        if self.cdata.basetype == lib.LY_TYPE_UNION:
+            for t in self.union_types():
+                yield from t.all_fraction_digits()
+        else:
+            fd = self.fraction_digits()
+            if fd is not None:
+                yield fd
+
     STR_TYPES = frozenset((STRING, BINARY, ENUM, IDENT, BITS))
 
     def length(self) -> Optional[str]:

tests/test_schema.py

@@ -477,6 +477,14 @@ def test_iter_tree(self):
         leaf = next(self.ctx.find_path("/yolo-system:conf"))
         self.assertEqual(len(list(leaf.iter_tree(full=True))), 23)
 
+    def test_leaf_type_fraction_digits(self):
+        self.ctx.load_module("yolo-nodetypes")
+        leaf = next(self.ctx.find_path("/yolo-nodetypes:conf/percentage"))
+        self.assertIsInstance(leaf, SLeaf)
+        t = leaf.type()
+        self.assertIsInstance(t, Type)
+        self.assertEqual(next(t.all_fraction_digits(), None), 2)
+
 
 # -------------------------------------------------------------------------------------
 class LeafTest(unittest.TestCase):