Add lambda values

blueprintcompiler/language/__init__.py

@@ -16,6 +16,7 @@ from .gtk_string_list import Strings
 from .gtk_styles import Styles
 from .gtkbuilder_child import Child
 from .gtkbuilder_template import Template
+from .lambdas import Lambda
 from .imports import GtkDirective, Import
 from .ui import UI
 from .values import IdentValue, TranslatedStringValue, FlagsValue, LiteralValue
@@ -47,4 +48,5 @@ VALUE_HOOKS.children = [
     FlagsValue,
     IdentValue,
     LiteralValue,
+    Lambda,
 ]

blueprintcompiler/language/common.py

@@ -33,3 +33,24 @@ from ..xml_emitter import XmlEmitter
 OBJECT_HOOKS = AnyOf()
 OBJECT_CONTENT_HOOKS = AnyOf()
 VALUE_HOOKS = AnyOf()
+
+
+class Scope:
+    def get_variables(self) -> T.Iterator[str]:
+        yield from self.get_objects().keys()
+
+    def get_objects(self) -> T.Dict[str, T.Any]:
+        raise NotImplementedError()
+
+    @property
+    def this_name(self) -> T.Optional[str]:
+        return None
+
+    @property
+    def this_type(self) -> T.Optional[str]:
+        return None
+
+    @property
+    def this_type_glib_name(self) -> T.Optional[str]:
+        return None
+

blueprintcompiler/language/expression.py

@@ -41,7 +41,14 @@ class InfixExpr(AstNode):
 class IdentExpr(AstNode):
     grammar = UseIdent("ident")
 
+    @property
+    def is_this(self):
+        return self.parent_by_type(Scope).this_name == self.tokens["ident"]
+
     def emit_xml(self, xml: XmlEmitter):
+        if self.is_this:
+            raise CompilerBugError()
+
         xml.start_tag("constant")
         xml.put_text(self.tokens["ident"])
         xml.end_tag()
@@ -51,6 +58,9 @@ class LookupOp(InfixExpr):
     grammar = [".", UseIdent("property")]
 
     def emit_xml(self, xml: XmlEmitter):
+        if isinstance(self.lhs, IdentExpr) and self.lhs.is_this:
+            xml.put_self_closing("lookup", name=self.tokens["property"], type=self.parent_by_type(Scope).this_type)
+        else:
             xml.start_tag("lookup", name=self.tokens["property"])
             self.lhs.emit_xml(xml)
             xml.end_tag()

blueprintcompiler/language/lambdas.py

@@ -0,0 +1,54 @@
+# lambdas.py
+#
+# Copyright 2022 James Westman <james@jwestman.net>
+#
+# This file is free software; you can redistribute it and/or modify it
+# under the terms of the GNU Lesser General Public License as
+# published by the Free Software Foundation; either version 3 of the
+# License, or (at your option) any later version.
+#
+# This file is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# SPDX-License-Identifier: LGPL-3.0-or-later
+
+
+from .types import TypeName
+from .expression import Expr
+from .values import Value
+from .common import *
+
+
+class Lambda(Value, Scope):
+    grammar = [
+        "(",
+        TypeName,
+        UseIdent("argument"),
+        ")",
+        "=>",
+        Expr,
+    ]
+
+    def emit_xml(self, xml: XmlEmitter):
+        for child in self.children:
+            child.emit_xml(xml)
+
+    def get_objects(self):
+        return {
+            **self.parent.parent_by_type(Scope).get_objects(),
+            self.tokens["argument"]: None,
+        }
+
+    @property
+    def this_name(self) -> str:
+        return self.tokens["argument"]
+
+    @property
+    def this_type(self) -> str:
+        return self.children[TypeName][0].gir_type
+

blueprintcompiler/language/ui.py

@@ -24,7 +24,7 @@ from .gtkbuilder_template import Template
 from .common import *
 
 
-class UI(AstNode):
+class UI(AstNode, Scope):
     """ The AST node for the entire file """
 
     grammar = [
@@ -62,6 +62,8 @@ class UI(AstNode):
     def objects_by_id(self):
         return { obj.tokens["id"]: obj for obj in self.iterate_children_recursive() if obj.tokens["id"] is not None }
 
+    def get_objects(self):
+        return self.objects_by_id
 
     @validate()
     def gir_errors(self):

tests/samples/lambda.blp

@@ -0,0 +1,9 @@
+using Gtk 4.0;
+
+Gtk.BoolFilter filter {
+  expression: (Gtk.Label object) => object.visible;
+}
+
+Gtk.BoolFilter {
+  expression: (Gtk.Label object) => filter.invert;
+}

tests/samples/lambda.ui

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<interface>
+  <requires lib="gtk" version="4.0"/>
+  <object class="GtkBoolFilter" id="filter">
+    <property name="expression">
+      <lookup name="visible" type="GtkLabel"/>
+    </property>
+  </object>
+  <object class="GtkBoolFilter">
+    <property name="expression">
+      <lookup name="invert">
+        <constant>filter</constant>
+      </lookup>
+    </property>
+  </object>
+</interface>

tests/test_samples.py

@@ -141,6 +141,7 @@ class TestSamples(unittest.TestCase):
         self.assert_sample("flags")
         self.assert_sample("id_prop")
         self.assert_sample("inline_menu")
+        self.assert_sample("lambda")
         self.assert_sample("layout")
         self.assert_sample("menu")
         self.assert_sample("numbers")