Change template syntax

Templates now use a TypeName instead of an identifier, which makes it
clearer that it's an extern symbol (or that it's a Gtk.ListItem).

blueprintcompiler/decompiler.py

@@ -57,6 +57,7 @@ class DecompileCtx:
         self._indent: int = 0
         self._blocks_need_end: T.List[str] = []
         self._last_line_type: LineType = LineType.NONE
+        self.template_class: T.Optional[str] = None
 
         self.gir.add_namespace(get_namespace("Gtk", "4.0"))
 
@@ -158,6 +159,8 @@ class DecompileCtx:
             )
         ):
             self.print(f'{name}: "{escape_quote(value)}";')
+        elif value == self.template_class:
+            self.print(f"{name}: template;")
         elif type.assignable_to(
             self.gir.namespaces["Gtk"].lookup_type("GObject.Object")
         ):

blueprintcompiler/gir.py

@@ -516,7 +516,7 @@ class Class(GirNode, GirType):
 
 
 class TemplateType(GirType):
-    def __init__(self, name: str, parent: T.Optional[Class]):
+    def __init__(self, name: str, parent: T.Optional[GirType]):
         self._name = name
         self.parent = parent
 
@@ -534,14 +534,14 @@ class TemplateType(GirType):
 
     @cached_property
     def properties(self) -> T.Mapping[str, Property]:
-        if self.parent is None or isinstance(self.parent, ExternType):
+        if not (isinstance(self.parent, Class) or isinstance(self.parent, Interface)):
             return {}
         else:
             return self.parent.properties
 
     @cached_property
     def signals(self) -> T.Mapping[str, Signal]:
-        if self.parent is None or isinstance(self.parent, ExternType):
+        if not (isinstance(self.parent, Class) or isinstance(self.parent, Interface)):
             return {}
         else:
             return self.parent.signals

blueprintcompiler/language/contexts.py

@@ -23,6 +23,7 @@ from functools import cached_property
 
 from .common import *
 from .gobject_object import Object
+from .gtkbuilder_template import Template
 
 
 @dataclass
@@ -51,8 +52,11 @@ class ScopeCtx:
 
             if obj.tokens["id"] in passed:
                 token = obj.group.tokens["id"]
+                if not isinstance(obj, Template):
                     raise CompileError(
-                    f"Duplicate object ID '{obj.tokens['id']}'", token.start, token.end
+                        f"Duplicate object ID '{obj.tokens['id']}'",
+                        token.start,
+                        token.end,
                     )
             passed[obj.tokens["id"]] = obj
 

blueprintcompiler/language/expression.py

@@ -85,9 +85,9 @@ class LiteralExpr(ExprBase):
     def is_object(self) -> bool:
         from .values import IdentLiteral
 
-        return (
-            isinstance(self.literal.value, IdentLiteral)
-            and self.literal.value.ident in self.context[ScopeCtx].objects
+        return isinstance(self.literal.value, IdentLiteral) and (
+            self.literal.value.ident in self.context[ScopeCtx].objects
+            or self.root.is_legacy_template(self.literal.value.ident)
         )
 
     @property

blueprintcompiler/language/gobject_object.py

@@ -49,7 +49,7 @@ class Object(AstNode):
         return self.tokens["id"]
 
     @property
-    def class_name(self) -> T.Optional[ClassName]:
+    def class_name(self) -> ClassName:
         return self.children[ClassName][0]
 
     @property
@@ -78,7 +78,9 @@ class Object(AstNode):
 
     @validate("id")
     def object_id_not_reserved(self):
-        if self.id in RESERVED_IDS:
+        from .gtkbuilder_template import Template
+
+        if not isinstance(self, Template) and self.id in RESERVED_IDS:
             raise CompileWarning(f"{self.id} may be a confusing object ID")
 
 

blueprintcompiler/language/gtkbuilder_template.py

@@ -19,15 +19,18 @@
 
 import typing as T
 
+from blueprintcompiler.language.common import GirType
+
 from .gobject_object import Object, ObjectContent
 from .common import *
-from .types import ClassName
+from ..gir import TemplateType
+from .types import ClassName, TemplateClassName
 
 
 class Template(Object):
     grammar = [
-        "template",
-        UseIdent("id").expected("template class name"),
+        UseExact("id", "template"),
+        to_parse_node(TemplateClassName).expected("template type"),
         Optional(
             [
                 Match(":"),
@@ -39,21 +42,29 @@ class Template(Object):
 
     @property
     def id(self) -> str:
-        return self.tokens["id"]
+        return "template"
 
     @property
-    def class_name(self) -> T.Optional[ClassName]:
-        if len(self.children[ClassName]):
-            return self.children[ClassName][0]
+    def gir_class(self) -> GirType:
+        if isinstance(self.class_name.gir_type, ExternType):
+            if gir := self.parent_type:
+                return TemplateType(self.class_name.gir_type.full_name, gir.gir_type)
+        return self.class_name.gir_type
+
+    @property
+    def parent_type(self) -> T.Optional[ClassName]:
+        if len(self.children[ClassName]) == 2:
+            return self.children[ClassName][1]
         else:
             return None
 
-    @property
-    def gir_class(self):
-        if self.class_name is None:
-            return gir.TemplateType(self.id, None)
-        else:
-            return gir.TemplateType(self.id, self.class_name.gir_type)
+    @validate()
+    def parent_only_if_extern(self):
+        if not isinstance(self.class_name.gir_type, ExternType):
+            if self.parent_type is not None:
+                raise CompileError(
+                    "Parent type may only be specified if the template type is extern"
+                )
 
     @validate("id")
     def unique_in_parent(self):
@@ -63,10 +74,15 @@ class Template(Object):
 
 
 @decompiler("template")
-def decompile_template(ctx: DecompileCtx, gir, klass, parent="Widget"):
-    gir_class = ctx.type_by_cname(parent)
-    if gir_class is None:
-        ctx.print(f"template {klass} : .{parent} {{")
+def decompile_template(ctx: DecompileCtx, gir, klass, parent=None):
+    def class_name(cname: str) -> str:
+        if gir := ctx.type_by_cname(cname):
+            return decompile.full_name(gir)
         else:
-        ctx.print(f"template {klass} : {decompile.full_name(gir_class)} {{")
-    return gir_class
+            return "$" + cname
+
+    ctx.print(f"template {class_name(klass)} : {class_name(parent)} {{")
+
+    ctx.template_class = klass
+
+    return ctx.type_by_cname(klass) or ctx.type_by_cname(parent)

blueprintcompiler/language/property_binding.py

@@ -70,6 +70,8 @@ class PropertyBinding(AstNode):
 
     @property
     def source_obj(self) -> T.Optional[Object]:
+        if self.root.is_legacy_template(self.source):
+            return self.root.template
         return self.context[ScopeCtx].objects.get(self.source)
 
     @property
@@ -127,3 +129,11 @@ class PropertyBinding(AstNode):
                 "Use 'bind-property', introduced in blueprint 0.8.0, to use binding flags",
                 actions=[CodeAction("Use 'bind-property'", "bind-property")],
             )
+
+    @validate("source")
+    def legacy_template(self):
+        if self.root.is_legacy_template(self.source):
+            raise UpgradeWarning(
+                "Use 'template' instead of the class name (introduced in 0.8.0)",
+                actions=[CodeAction("Use 'template'", "template")],
+            )

blueprintcompiler/language/types.py

@@ -122,3 +122,42 @@ class ConcreteClassName(ClassName):
                 f"{self.gir_type.full_name} can't be instantiated because it's abstract",
                 hints=[f"did you mean to use a subclass of {self.gir_type.full_name}?"],
             )
+
+
+class TemplateClassName(ClassName):
+    """Handles the special case of a template type. The old syntax uses an identifier,
+    which is ambiguous with the new syntax. So this class displays an appropriate
+    upgrade warning instead of a class not found error."""
+
+    @property
+    def is_legacy(self):
+        return (
+            self.tokens["extern"] is None
+            and self.tokens["namespace"] is None
+            and self.root.gir.get_type(self.tokens["class_name"], "Gtk") is None
+        )
+
+    @property
+    def gir_type(self) -> gir.GirType:
+        if self.is_legacy:
+            return gir.ExternType(self.tokens["class_name"])
+        else:
+            return super().gir_type
+
+    @validate("class_name")
+    def type_exists(self):
+        if self.is_legacy:
+            if type := self.root.gir.get_type_by_cname(self.tokens["class_name"]):
+                replacement = type.full_name
+            else:
+                replacement = "$" + self.tokens["class_name"]
+
+            raise UpgradeWarning(
+                "Use type syntax here (introduced in blueprint 0.8.0)",
+                actions=[CodeAction("Use type syntax", replace_with=replacement)],
+            )
+
+        if not self.tokens["extern"] and self.gir_ns is not None:
+            self.root.gir.validate_type(
+                self.tokens["class_name"], self.tokens["namespace"]
+            )

blueprintcompiler/language/ui.py

@@ -43,7 +43,7 @@ class UI(AstNode):
     ]
 
     @property
-    def gir(self):
+    def gir(self) -> gir.GirContext:
         gir_ctx = gir.GirContext()
         self._gir_errors = []
 
@@ -84,6 +84,20 @@ class UI(AstNode):
             or isinstance(child, Menu)
         ]
 
+    @property
+    def template(self) -> T.Optional[Template]:
+        if len(self.children[Template]):
+            return self.children[Template][0]
+        else:
+            return None
+
+    def is_legacy_template(self, id: str) -> bool:
+        return (
+            id not in self.context[ScopeCtx].objects
+            and self.template is not None
+            and self.template.class_name.glib_type_name == id
+        )
+
     @context(ScopeCtx)
     def scope_ctx(self) -> ScopeCtx:
         return ScopeCtx(node=self)

blueprintcompiler/language/values.py

@@ -260,6 +260,8 @@ class IdentLiteral(AstNode):
             return gir.BoolType()
         elif object := self.context[ScopeCtx].objects.get(self.ident):
             return object.gir_class
+        elif self.root.is_legacy_template(self.ident):
+            return self.root.template.class_name.gir_type
         else:
             return None
 
@@ -277,6 +279,12 @@ class IdentLiteral(AstNode):
                     did_you_mean=(self.ident, list(expected_type.members.keys())),
                 )
 
+        elif self.root.is_legacy_template(self.ident):
+            raise UpgradeWarning(
+                "Use 'template' instead of the class name (introduced in 0.8.0)",
+                actions=[CodeAction("Use 'template'", "template")],
+            )
+
         elif expected_type is not None:
             object = self.context[ScopeCtx].objects.get(self.ident)
             if object is None:

blueprintcompiler/outputs/xml/__init__.py

@@ -8,6 +8,7 @@ from .xml_emitter import XmlEmitter
 class XmlOutput(OutputFormat):
     def emit(self, ui: UI) -> str:
         xml = XmlEmitter()
+        self._ui = ui
         self._emit_ui(ui, xml)
         return xml.result
 
@@ -32,7 +33,9 @@ class XmlOutput(OutputFormat):
         xml.put_self_closing("requires", lib="gtk", version=gtk.gir_namespace.version)
 
     def _emit_template(self, template: Template, xml: XmlEmitter):
-        xml.start_tag("template", **{"class": template.id}, parent=template.class_name)
+        xml.start_tag(
+            "template", **{"class": template.gir_class}, parent=template.parent_type
+        )
         self._emit_object_or_template(template, xml)
         xml.end_tag()
 
@@ -188,6 +191,8 @@ class XmlOutput(OutputFormat):
                 xml.put_text(value.ident)
             elif isinstance(value_type, gir.Enumeration):
                 xml.put_text(str(value_type.members[value.ident].value))
+            elif value.ident == "template" and self._ui.template is not None:
+                xml.put_text(self._ui.template.gir_class.glib_type_name)
             else:
                 xml.put_text(value.ident)
         elif isinstance(value, TypeLiteral):

tests/sample_errors/abstract_class.blp

@@ -1,4 +1,4 @@
 using Gtk 4.0;
 
-template MyWidget : Gtk.Widget {}
+template $MyWidget : Gtk.Widget {}
 Gtk.Widget {}

tests/sample_errors/class_dne.blp

@@ -1,3 +1,3 @@
 using Gtk 4.0;
 
-template TestTemplate : Gtk.NotARealClass {}
+template $TestTemplate : Gtk.NotARealClass {}

tests/sample_errors/class_dne.err

@@ -1 +1 @@
-3,29,13,Namespace Gtk does not contain a type called NotARealClass
+3,30,13,Namespace Gtk does not contain a type called NotARealClass

tests/sample_errors/expr_cast_needed.blp

@@ -1,7 +1,5 @@
 using Gtk 4.0;
 
-template GtkListItem {
-  Label {
-    label: bind GtkListItem.item.label;
-  }
+$MyObject object {
+  foo: bind object.bar.baz;
 }

tests/sample_errors/expr_cast_needed.err

@@ -1 +1 @@
-5,34,5,Could not determine the type of the preceding expression
+4,24,3,Could not determine the type of the preceding expression

tests/sample_errors/legacy_template.blp

@@ -0,0 +1,10 @@
+using Gtk 4.0;
+
+template TestTemplate : ApplicationWindow {
+  test-property: "Hello, world";
+  test-signal => $on_test_signal();
+}
+
+Dialog {
+  transient-for: TestTemplate;
+}

tests/sample_errors/legacy_template.err

@@ -0,0 +1,2 @@
+3,10,12,Use type syntax here (introduced in blueprint 0.8.0)
+9,18,12,Use 'template' instead of the class name (introduced in 0.8.0)

tests/sample_errors/not_a_class.blp

@@ -1,3 +1,3 @@
 using Gtk 4.0;
 
-template TestTemplate : Gtk.Orientable {}
+template $TestTemplate : Gtk.Orientable {}

tests/sample_errors/not_a_class.err

@@ -1 +1 @@
-3,25,14,Gtk.Orientable is an interface, not a class
+3,26,14,Gtk.Orientable is an interface, not a class

tests/sample_errors/ns_not_imported.blp

@@ -1,3 +1,3 @@
 using Gtk 4.0;
 
-template TestTemplate : Adw.ApplicationWindow {}
+template $TestTemplate : Adw.ApplicationWindow {}

tests/sample_errors/ns_not_imported.err

@@ -1 +1 @@
-3,25,3,Namespace Adw was not imported
+3,26,3,Namespace Adw was not imported

tests/sample_errors/template_parent.blp

@@ -0,0 +1,3 @@
+using Gtk 4.0;
+
+template Gtk.ListItem : $WrongParent {}

tests/sample_errors/template_parent.err

@@ -0,0 +1 @@
+3,1,39,Parent type may only be specified if the template type is extern

tests/sample_errors/two_templates.blp

@@ -1,4 +1,6 @@
 using Gtk 4.0;
 
-template ClassName : Gtk.Button {}
-template ClassName2 : Gtk.Button {}
+template $ClassName : Gtk.Button {}
+template $ClassName2 : Gtk.Button {}
+
+Label template {}

tests/sample_errors/two_templates.err

@@ -1 +1,2 @@
-4,10,10,Only one template may be defined per file, but this file contains 2
+6,7,8,Duplicate object ID 'template'
+4,1,8,Only one template may be defined per file, but this file contains 2

tests/samples/template.blp

@@ -1,10 +1,10 @@
 using Gtk 4.0;
 
-template TestTemplate : ApplicationWindow {
+template $TestTemplate : ApplicationWindow {
   test-property: "Hello, world";
   test-signal => $on_test_signal();
 }
 
 Dialog {
-  transient-for: TestTemplate;
+  transient-for: template;
 }

tests/samples/template_binding.blp

@@ -1,5 +1,5 @@
 using Gtk 4.0;
 
-template MyTemplate : Box {
-  prop1: bind MyTemplate.prop2 as <$MyObject>.prop3;
+template $MyTemplate : Box {
+  prop1: bind template.prop2 as <$MyObject>.prop3;
 }

tests/samples/template_binding_extern.blp

@@ -1,5 +1,5 @@
 using Gtk 4.0;
 
-template MyTemplate : $MyParentClass {
-  prop1: bind MyTemplate.prop2 as <$MyObject>.prop3;
+template $MyTemplate : $MyParentClass {
+  prop1: bind template.prop2 as <$MyObject>.prop3;
 }

tests/samples/template_no_parent.blp

@@ -1,3 +1,3 @@
 using Gtk 4.0;
 
-template GtkListItem {}
+template Gtk.ListItem {}

tests/test_samples.py

@@ -266,6 +266,7 @@ class TestSamples(unittest.TestCase):
         self.assert_sample_error("inline_menu")
         self.assert_sample_error("invalid_bool")
         self.assert_sample_error("layout_in_non_widget")
+        self.assert_sample_error("legacy_template")
         self.assert_sample_error("menu_no_id")
         self.assert_sample_error("menu_toplevel_attribute")
         self.assert_sample_error("no_import_version")
@@ -284,6 +285,7 @@ class TestSamples(unittest.TestCase):
         self.assert_sample_error("strv")
         self.assert_sample_error("styles_in_non_widget")
         self.assert_sample_error("subscope")
+        self.assert_sample_error("template_parent")
         self.assert_sample_error("two_templates")
         self.assert_sample_error("uint")
         self.assert_sample_error("using_invalid_namespace")