From c155ba7b15f91daf51a514085902ed5fa8e51c1e Mon Sep 17 00:00:00 2001
From: James Westman <james@jwestman.net>
Date: Sat, 30 Oct 2021 20:03:37 -0500
Subject: [PATCH] Add layouts

---
 docs/examples.rst          | 18 ++++++++++++++++++
 gtkblueprinttool/ast.py    | 34 ++++++++++++++++++++++++++++++----
 gtkblueprinttool/parser.py | 19 +++++++++++++++++++
 3 files changed, 67 insertions(+), 4 deletions(-)

diff --git a/docs/examples.rst b/docs/examples.rst
index 093c2cb..402d4dd 100644
--- a/docs/examples.rst
+++ b/docs/examples.rst
@@ -243,3 +243,21 @@ on one line. The action and icon are optional.
    menu {
      item _("Copy") "app.copy" "copy-symbolic";
    }
+
+
+Layout Properties
+-----------------
+
+Basic Usage
+~~~~~~~~~~~
+
+.. code-block::
+
+   Gtk.Grid {
+     Gtk.Label {
+       layout {
+         row: 0;
+         column: 1;
+       }
+     }
+   }
diff --git a/gtkblueprinttool/ast.py b/gtkblueprinttool/ast.py
index 2225b31..b0b699a 100644
--- a/gtkblueprinttool/ast.py
+++ b/gtkblueprinttool/ast.py
@@ -263,12 +263,13 @@ class Child(AstNode):
 
 class ObjectContent(AstNode):
     child_type = "object_content"
-    def __init__(self, properties=[], signals=[], children=[], style=[]):
+    def __init__(self, properties=[], signals=[], children=[], style=[], layout=None):
         super().__init__()
         self.properties = properties
         self.signals = signals
         self.children = children
         self.style = style
+        self.layout = layout or []
 
 
     @validate()
@@ -290,7 +291,7 @@ class ObjectContent(AstNode):
             )
 
     def emit_xml(self, xml: XmlEmitter):
-        for x in [*self.properties, *self.signals, *self.children, *self.style]:
+        for x in self.child_nodes:
             x.emit_xml(xml)
 
 
@@ -476,8 +477,9 @@ class Menu(AstNode):
         xml.end_tag()
 
 
-class MenuAttribute(AstNode):
+class BaseAttribute(AstNode):
     child_type = "attributes"
+    tag_name: str = ""
 
     def __init__(self, name=None, value=None, translatable=False):
         super().__init__()
@@ -487,9 +489,33 @@ class MenuAttribute(AstNode):
 
     def emit_xml(self, xml: XmlEmitter):
         xml.start_tag(
-            "attribute",
+            self.tag_name,
              name=self.name,
              translatable="yes" if self.translatable else None,
         )
         xml.put_text(str(self.value))
         xml.end_tag()
+
+
+class MenuAttribute(BaseAttribute):
+    child_type = "attributes"
+    tag_name = "attribute"
+
+
+class Layout(AstNode):
+    child_type = "layout"
+
+    def __init__(self, layout_props=None):
+        super().__init__()
+        self.layout_props = layout_props or []
+
+    def emit_xml(self, xml: XmlEmitter):
+        xml.start_tag("layout")
+        for prop in self.layout_props:
+            prop.emit_xml(xml)
+        xml.end_tag()
+
+
+class LayoutProperty(BaseAttribute):
+    child_type = "layout_props"
+    tag_name = "property"
diff --git a/gtkblueprinttool/parser.py b/gtkblueprinttool/parser.py
index 9017bca..3855bfe 100644
--- a/gtkblueprinttool/parser.py
+++ b/gtkblueprinttool/parser.py
@@ -244,12 +244,31 @@ def parse(tokens) -> T.Tuple[ast.UI, T.Optional[MultipleErrors]]:
         ),
     )
 
+    layout_prop = Group(
+        ast.LayoutProperty,
+        Statement(
+            UseIdent("name"),
+            Op(":"),
+            value.expected("a value"),
+        )
+    )
+
+    layout = Group(
+        ast.Layout,
+        Sequence(
+            Keyword("layout"),
+            OpenBlock().expected("`{`"),
+            Until(layout_prop, CloseBlock()),
+        )
+    )
+
     object_content = Group(
         ast.ObjectContent,
         Sequence(
             OpenBlock(),
             Until(AnyOf(
                 style,
+                layout,
                 binding,
                 property,
                 signal,