Move bindings out of the Value syntax

They're only valid in properties, so they should just be there. Same
with object values.

blueprintcompiler/language/binding.py

@@ -47,11 +47,6 @@ class Binding(AstNode):
                     )
         return None
 
-    @validate("bind")
-    def not_bindable(self) -> None:
-        if binding_error := self.context[ValueTypeCtx].binding_error:
-            raise binding_error
-
 
 @dataclass
 class SimpleBinding:

blueprintcompiler/language/contexts.py

@@ -25,4 +25,3 @@ from .common import *
 @dataclass
 class ValueTypeCtx:
     value_type: T.Optional[GirType]
-    binding_error: T.Optional[CompileError] = None

blueprintcompiler/language/gobject_property.py

@@ -22,7 +22,7 @@ from dataclasses import dataclass
 from .expression import ExprChain
 from .gobject_object import Object
 from .gtkbuilder_template import Template
-from .values import Value, Translated
+from .values import Value, ObjectValue
 from .common import *
 from .contexts import ValueTypeCtx
 from .property_binding import PropertyBinding
@@ -30,14 +30,16 @@ from .binding import Binding
 
 
 class Property(AstNode):
-    grammar = Statement(UseIdent("name"), ":", Value)
+    grammar = Statement(
+        UseIdent("name"), ":", AnyOf(PropertyBinding, Binding, ObjectValue, Value)
+    )
 
     @property
     def name(self) -> str:
         return self.tokens["name"]
 
     @property
-    def value(self) -> Value:
+    def value(self) -> T.Union[PropertyBinding, Binding, ObjectValue, Value]:
         return self.children[0]
 
     @property
@@ -49,29 +51,26 @@ class Property(AstNode):
         if self.gir_class is not None and not isinstance(self.gir_class, ExternType):
             return self.gir_class.properties.get(self.tokens["name"])
 
-    @context(ValueTypeCtx)
-    def value_type(self) -> ValueTypeCtx:
+    @validate()
+    def binding_valid(self):
         if (
-            (
-                isinstance(self.value.child, PropertyBinding)
-                or isinstance(self.value.child, Binding)
-            )
+            (isinstance(self.value, PropertyBinding) or isinstance(self.value, Binding))
             and self.gir_property is not None
             and self.gir_property.construct_only
         ):
-            binding_error = CompileError(
+            raise CompileError(
                 f"{self.gir_property.full_name} can't be bound because it is construct-only",
                 hints=["construct-only properties may only be set to a static value"],
             )
-        else:
-            binding_error = None
 
+    @context(ValueTypeCtx)
+    def value_type(self) -> ValueTypeCtx:
         if self.gir_property is not None:
             type = self.gir_property.type
         else:
             type = None
 
-        return ValueTypeCtx(type, binding_error)
+        return ValueTypeCtx(type)
 
     @validate("name")
     def property_exists(self):

blueprintcompiler/language/property_binding.py

@@ -121,11 +121,6 @@ class PropertyBinding(AstNode):
                 f"{gir_class.full_name} does not have a property called {self.property_name}"
             )
 
-    @validate("bind-property")
-    def not_bindable(self) -> None:
-        if binding_error := self.context[ValueTypeCtx].binding_error:
-            raise binding_error
-
     @validate("bind")
     def old_bind(self):
         if self.tokens["bind"]:

blueprintcompiler/language/values.py

@@ -361,12 +361,12 @@ class ObjectValue(AstNode):
 
 
 class Value(AstNode):
-    grammar = AnyOf(PropertyBinding, Binding, Translated, ObjectValue, Flags, Literal)
+    grammar = AnyOf(Translated, Flags, Literal)
 
     @property
     def child(
         self,
-    ) -> T.Union[PropertyBinding, Binding, Translated, ObjectValue, Flags, Literal]:
+    ) -> T.Union[Translated, Flags, Literal]:
         return self.children[0]
 
 

blueprintcompiler/outputs/xml/__init__.py

@@ -91,48 +91,58 @@ class XmlOutput(OutputFormat):
 
     def _emit_property(self, property: Property, xml: XmlEmitter):
         value = property.value
-        child = value.child
 
         props: T.Dict[str, T.Optional[str]] = {
             "name": property.name,
         }
 
+        if isinstance(value, Value):
+            child = value.child
+
             if isinstance(child, Translated):
-            xml.start_tag("property", **props, **self._translated_string_attrs(child))
+                xml.start_tag(
+                    "property", **props, **self._translated_string_attrs(child)
+                )
                 xml.put_text(child.child.string)
                 xml.end_tag()
-        elif isinstance(child, Object):
+            else:
                 xml.start_tag("property", **props)
-            self._emit_object(child, xml)
+                self._emit_value(value, xml)
                 xml.end_tag()
-        elif isinstance(child, Binding):
-            if simple := child.simple_binding:
+
+        elif isinstance(value, Binding):
+            if simple := value.simple_binding:
                 props["bind-source"] = simple.source
                 props["bind-property"] = simple.property_name
                 props["bind-flags"] = "sync-create"
                 xml.put_self_closing("property", **props)
             else:
                 xml.start_tag("binding", **props)
-                self._emit_expression(child.expression, xml)
+                self._emit_expression(value.expression, xml)
                 xml.end_tag()
-        elif isinstance(child, PropertyBinding):
+
+        elif isinstance(value, PropertyBinding):
             bind_flags = []
-            if not child.no_sync_create:
+            if not value.no_sync_create:
                 bind_flags.append("sync-create")
-            if child.inverted:
+            if value.inverted:
                 bind_flags.append("invert-boolean")
-            if child.bidirectional:
+            if value.bidirectional:
                 bind_flags.append("bidirectional")
 
-            props["bind-source"] = child.source
-            props["bind-property"] = child.property_name
+            props["bind-source"] = value.source
+            props["bind-property"] = value.property_name
             props["bind-flags"] = "|".join(bind_flags) or None
             xml.put_self_closing("property", **props)
-        else:
+
+        elif isinstance(value, ObjectValue):
             xml.start_tag("property", **props)
-            self._emit_value(value, xml)
+            self._emit_object(value.object, xml)
             xml.end_tag()
 
+        else:
+            raise CompilerBugError()
+
     def _translated_string_attrs(
         self, translated: T.Union[QuotedLiteral, Translated]
     ) -> T.Dict[str, T.Optional[str]]:

tests/sample_errors/read_only_properties.err

@@ -1,2 +1,2 @@
-4,14,4,ComboBox.has-entry can't be bound because it is construct-only
+4,3,34,ComboBox.has-entry can't be bound because it is construct-only
 5,3,12,Widget.scale-factor is not writable