preliminary variant syntax

blueprintcompiler/language/gobject_property.py

@@ -22,12 +22,12 @@ from .binding import Binding
 from .common import *
 from .contexts import ValueTypeCtx
 from .gtkbuilder_template import Template
-from .values import ArrayValue, ObjectValue, Value
+from .values import ArrayValue, ObjectValue, Value, VariantValue
 
 
 class Property(AstNode):
     grammar = Statement(
-        UseIdent("name"), ":", AnyOf(Binding, ObjectValue, Value, ArrayValue)
+        UseIdent("name"), ":", AnyOf(Binding, VariantValue, ObjectValue, Value, ArrayValue)
     )
 
     @property
@@ -35,7 +35,7 @@ class Property(AstNode):
         return self.tokens["name"]
 
     @property
-    def value(self) -> T.Union[Binding, ObjectValue, Value, ArrayValue]:
+    def value(self) -> T.Union[Binding, VariantValue, ObjectValue, Value, ArrayValue]:
         return self.children[0]
 
     @property

blueprintcompiler/language/values.py

@@ -371,6 +371,42 @@ class IdentLiteral(AstNode):
         else:
             return None
 
+class VariantValue(AstNode):
+    grammar = [
+        "variant",
+        "<",
+        UseQuoted("type"),
+        ">",
+        "(",
+        UseQuoted("value"),
+        ")"
+    ]
+
+    @property
+    def var_type(self) -> str:
+        return self.tokens["type"]
+
+    @property
+    def var_value(self) -> str:
+        return self.tokens["value"]
+
+    @validate()
+    def validate_for_type(self) -> None:
+        expected_type = self.context[ValueTypeCtx].value_type
+        if (
+            isinstance(expected_type, gir.IntType)
+            or isinstance(expected_type, gir.UIntType)
+            or isinstance(expected_type, gir.FloatType)
+            or isinstance(expected_type, gir.FloatType)
+        ):
+            raise CompileError(f"Cannot convert variant to number")
+        elif isinstance(expected_type, gir.StringType):
+            raise CompileError("Cannot convert variant to string")
+        if isinstance(expected_type, gir.Boxed) and expected_type.full_name == "GLib.Variant":
+            pass
+        else:
+            raise CompileError(f"Cannot convert variant into {expected_type.full_name}")
+        pass
 
 class Literal(AstNode):
     grammar = AnyOf(

blueprintcompiler/outputs/xml/__init__.py

@@ -1,5 +1,7 @@
 import typing as T
 
+from blueprintcompiler.language.values import VariantValue
+
 from ...language import *
 from .. import OutputFormat
 from .xml_emitter import XmlEmitter
@@ -148,6 +150,11 @@ class XmlOutput(OutputFormat):
             self._emit_value(values[-1], xml)
             xml.end_tag()
 
+        elif isinstance(value, VariantValue):
+            xml.start_tag("property", **props, **{"type": value.var_type})
+            xml.put_text(value.var_value)
+            xml.end_tag()
+
         else:
             raise CompilerBugError()
 
@@ -205,6 +212,8 @@ class XmlOutput(OutputFormat):
                 xml.put_text(self._object_id(value, value.ident))
         elif isinstance(value, TypeLiteral):
             xml.put_text(value.type_name.glib_type_name)
+        elif isinstance(value, VariantValue):
+            xml.put_text(value.value)
         else:
             if isinstance(value.value, float) and value.value == int(value.value):
                 xml.put_text(int(value.value))
@@ -284,6 +293,10 @@ class XmlOutput(OutputFormat):
             xml.start_tag(tag, **attrs)
             xml.put_text(value.child.value)
             xml.end_tag()
+        elif isinstance(value.child, VariantValue):
+            xml.start_tag(tag, **attrs, type=value.child.var_type)
+            xml.put_text(value.child.var_value)
+            xml.end_tag()
         else:
             xml.start_tag(tag, **attrs)
             self._emit_value(value, xml)

variant-test.blp

@@ -0,0 +1,6 @@
+using Gtk 4.0;
+
+Button {
+  action-name: "app.shave_yak";
+  action-target: variant<"y">("8");
+}