Add `default-value` annotation

An escape hatch to specify a freeform string for the default value of a
property.

Fixes: #4

5 files changed, 37 insertions, 7 deletions

diff --git a/docs/website/annotations/giannotations.rst b/docs/website/annotations/giannotations.rst
index 3e4bfa92..8099bd5b 100644
--- a/docs/website/annotations/giannotations.rst
+++ b/docs/website/annotations/giannotations.rst
@@ -129,6 +129,10 @@ Support for GObject objects
     - identifier (only applies to methods)
     - This signal is emitted by the given method
     -
+  * - ``(default-value VALUE)``
+    - identifier (only applies to properties)
+    - The default value of a GObject property, as a freeform string
+    - :issue:`4`
 
 
 Support for GObject closures
diff --git a/giscanner/annotationparser.py b/giscanner/annotationparser.py
index bce99804..3952b24b 100644
--- a/giscanner/annotationparser.py
+++ b/giscanner/annotationparser.py
@@ -193,6 +193,7 @@ ANN_ARRAY = 'array'
 ANN_ATTRIBUTES = 'attributes'
 ANN_CLOSURE = 'closure'
 ANN_CONSTRUCTOR = 'constructor'
+ANN_DEFAULT_VALUE = 'default-value'
 ANN_DESTROY = 'destroy'
 ANN_ELEMENT_TYPE = 'element-type'
 ANN_EMITTER = 'emitter'
@@ -228,6 +229,7 @@ GI_ANNS = [ANN_ALLOW_NONE,
            ANN_ATTRIBUTES,
            ANN_CLOSURE,
            ANN_CONSTRUCTOR,
+           ANN_DEFAULT_VALUE,
            ANN_DESTROY,
            ANN_ELEMENT_TYPE,
            ANN_EMITTER,
@@ -788,6 +790,19 @@ class GtkDocAnnotatable(object):
 
         self._validate_annotation(position, ann_name, options, exact_n_options=0)
 
+    def _do_validate_default_value(self, position, ann_name, options):
+        '''
+        Validate the ``(default-value)`` annotation.
+
+        :param position: :class:`giscanner.message.Position` of the line in the source file
+                         containing the annotation to be validated
+        :param ann_name: name of the annotation holding the options to validate
+        :param options: annotation options to validate
+        '''
+
+        # The 'default-value' annotation allows free form annotations.
+        pass
+
     def _do_validate_destroy(self, position, ann_name, options):
         '''
         Validate the ``(destroy)`` annotation.
@@ -1167,6 +1182,7 @@ class GtkDocCommentBlock(GtkDocAnnotatable):
     valid_annotations = (
         ANN_ATTRIBUTES,
         ANN_CONSTRUCTOR,
+        ANN_DEFAULT_VALUE,
         ANN_EMITTER,
         ANN_FOREIGN,
         ANN_GET_PROPERTY,
diff --git a/giscanner/maintransformer.py b/giscanner/maintransformer.py
index 2004d254..285712c7 100644
--- a/giscanner/maintransformer.py
+++ b/giscanner/maintransformer.py
@@ -28,6 +28,7 @@ from .annotationparser import (
     ANN_ATTRIBUTES,
     ANN_CLOSURE,
     ANN_CONSTRUCTOR,
+    ANN_DEFAULT_VALUE,
     ANN_DESTROY,
     ANN_ELEMENT_TYPE,
     ANN_EMITTER,
@@ -963,6 +964,9 @@ class MainTransformer(object):
         getter = block.annotations.get(ANN_GETTER)
         if getter:
             prop.getter = getter[0]
+        default_value = block.annotations.get(ANN_DEFAULT_VALUE)
+        if default_value:
+            prop.default_value = default_value[0]
 
     def _apply_annotations_signal(self, parent, signal):
         names = []
diff --git a/tests/scanner/Regress-1.0-expected.gir b/tests/scanner/Regress-1.0-expected.gir
index 608f120c..d6ca9dc6 100644
--- a/tests/scanner/Regress-1.0-expected.gir
+++ b/tests/scanner/Regress-1.0-expected.gir
@@ -4870,7 +4870,10 @@ raise an error.</doc>
                 default-value="1.000000">
         <type name="gfloat" c:type="gfloat"/>
       </property>
-      <property name="gtype" writable="1" transfer-ownership="none">
+      <property name="gtype"
+                writable="1"
+                transfer-ownership="none"
+                default-value="G_TYPE_INVALID">
         <type name="GType" c:type="GType"/>
       </property>
       <property name="hash-table" writable="1" transfer-ownership="container">
@@ -4893,7 +4896,10 @@ raise an error.</doc>
                 default-value="0">
         <type name="gint" c:type="gint"/>
       </property>
-      <property name="list" writable="1" transfer-ownership="none">
+      <property name="list"
+                writable="1"
+                transfer-ownership="none"
+                default-value="NULL">
         <type name="GLib.List" c:type="gpointer">
           <type name="utf8"/>
         </type>
diff --git a/tests/scanner/regress.c b/tests/scanner/regress.c
index e21997de..15430bd1 100644
--- a/tests/scanner/regress.c
+++ b/tests/scanner/regress.c
@@ -2643,7 +2643,7 @@ regress_test_obj_class_init (RegressTestObjClass *klass)
                                    pspec);
 
   /**
-   * RegressTestObj:list: (type GLib.List(utf8)) (transfer none)
+   * RegressTestObj:list: (type GLib.List(utf8)) (transfer none) (default-value NULL)
    */
   pspec = g_param_spec_pointer ("list",
                                 "GList property",
@@ -2745,7 +2745,7 @@ regress_test_obj_class_init (RegressTestObjClass *klass)
 
 
   /**
-   * TestObj:gtype:
+   * RegressTestObj:gtype: (default-value G_TYPE_INVALID)
    */
   pspec = g_param_spec_gtype ("gtype",
                               "GType property",
@@ -2757,7 +2757,7 @@ regress_test_obj_class_init (RegressTestObjClass *klass)
                                    pspec);
 
   /**
-   * TestObj:name-conflict:
+   * RegressTestObj:name-conflict:
    */
   pspec = g_param_spec_int ("name-conflict",
                             "name-conflict property",
@@ -2771,7 +2771,7 @@ regress_test_obj_class_init (RegressTestObjClass *klass)
                                    pspec);
 
   /**
-   * TestObj:byte-array:
+   * RegressTestObj:byte-array:
    */
   pspec = g_param_spec_boxed ("byte-array",
                               "GByteArray property",
@@ -2783,7 +2783,7 @@ regress_test_obj_class_init (RegressTestObjClass *klass)
                                    pspec);
 
   /**
-   * TestObj:write-only:
+   * RegressTestObj:write-only:
    */
   pspec = g_param_spec_boolean ("write-only", "Write-only property",
                                 "A write-only bool property that resets the value of TestObj:int to 0 when true",