Improve value parsing

Parse values as different AST nodes rather than just strings. This
allows for better validation and will eventually make expressions
possible.

tests/samples/flags.blp

@@ -0,0 +1,6 @@
+using Gtk 4.0;
+using Gio 2.0;
+
+Gio.Application {
+  flags: is_service | handles_open;
+}

tests/samples/flags.ui

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<interface>
+  <requires lib="gtk" version="4.0"/>
+  <object class="GApplication">
+    <property name="flags">is_service|handles_open</property>
+  </object>
+</interface>

tests/samples/menu.ui

@@ -2,7 +2,7 @@
 <interface>
   <requires lib="gtk" version="4.0"/>
   <menu>
-    <attribute name="label" translatable="yes">menu label</attribute>
+    <attribute name="label" translatable="true">menu label</attribute>
     <attribute name="test-custom-attribute">3.1415</attribute>
     <submenu>
       <section>

tests/samples/property.blp

@@ -1,5 +1,5 @@
 using Gtk 4.0;
 
 Box {
-  orientation: VERTICAL;
+  orientation: vertical;
 }

tests/samples/property.ui

@@ -2,6 +2,6 @@
 <interface>
   <requires lib="gtk" version="4.0"/>
   <object class="GtkBox">
-    <property name="orientation">VERTICAL</property>
+    <property name="orientation">vertical</property>
   </object>
 </interface>

tests/test_samples.py

@@ -20,38 +20,44 @@
 
 import difflib # I love Python
 from pathlib import Path
+import traceback
 import unittest
 
 from gtkblueprinttool import tokenizer, parser
-from gtkblueprinttool.errors import PrintableError
+from gtkblueprinttool.errors import PrintableError, MultipleErrors
 from gtkblueprinttool.tokenizer import Token, TokenType, tokenize
 
 
 class TestSamples(unittest.TestCase):
     def assert_sample(self, name):
-        with open((Path(__file__).parent / f"samples/{name}.blp").resolve()) as f:
-            blueprint = f.read()
-        with open((Path(__file__).parent / f"samples/{name}.ui").resolve()) as f:
-            expected = f.read()
+        try:
+            with open((Path(__file__).parent / f"samples/{name}.blp").resolve()) as f:
+                blueprint = f.read()
+            with open((Path(__file__).parent / f"samples/{name}.ui").resolve()) as f:
+                expected = f.read()
 
-        tokens = tokenizer.tokenize(blueprint)
-        ast, errors = parser.parse(tokens)
+            tokens = tokenizer.tokenize(blueprint)
+            ast, errors = parser.parse(tokens)
 
-        if errors:
-            raise errors
-        if len(ast.errors):
-            raise MultipleErrors(ast.errors)
+            if errors:
+                raise errors
+            if len(ast.errors):
+                raise MultipleErrors(ast.errors)
 
-        actual = ast.generate()
-        if actual.strip() != expected.strip():
-            diff = difflib.unified_diff(expected.splitlines(), actual.splitlines())
-            print("\n".join(diff))
+            actual = ast.generate()
+            if actual.strip() != expected.strip():
+                diff = difflib.unified_diff(expected.splitlines(), actual.splitlines())
+                print("\n".join(diff))
+                raise AssertionError()
+        except PrintableError as e:
+            e.pretty_print(name + ".blp", blueprint)
             raise AssertionError()
 
 
     def test_samples(self):
         self.assert_sample("binding")
         self.assert_sample("child_type")
+        self.assert_sample("flags")
         self.assert_sample("layout")
         self.assert_sample("menu")
         self.assert_sample("property")