Allow layouts to specify screen tags rather than indices - makes order of instantiation irrelevant in Model 1 etc.

scripts/build/complay.py

@@ -92,6 +92,7 @@ class XmlError(Exception):
 
 
 class LayoutChecker(Minifyer):
+    BADTAGPATTERN = re.compile('[^abcdefghijklmnopqrstuvwxyz0123456789_.:^$]')
     VARPATTERN = re.compile('^~scr(0|[1-9][0-9]*)(native[xy]aspect|width|height)~$')
     SHAPES = frozenset(('disk', 'led14seg', 'led14segsc', 'led16seg', 'led16segsc', 'led7seg', 'led8seg_gts1', 'rect'))
     OBJECTS = frozenset(('backdrop', 'bezel', 'cpanel', 'marquee', 'overlay'))
@@ -181,6 +182,21 @@ class LayoutChecker(Minifyer):
                         self.handleError('Element screen attribute index "%s" is negative' % (attrs['index'], ))
                 except:
                     self.handleError('Element screen attribute index "%s" is not an integer' % (attrs['index'], ))
+                if 'tag' in attrs:
+                    self.handleError('Element screen has both index and tag attributes');
+            if 'tag' in attrs:
+                tag = attrs['tag']
+                if '' == tag:
+                    self.handleError('Element screen attribute tag is empty')
+                else:
+                    if self.BADTAGPATTERN.search(tag):
+                        self.handleError('Element screen attribute tag "%s" contains invalid characters' % (tag, ));
+                    if tag.find('^') >= 0:
+                        self.handleError('Element screen attribute tag "%s" contains parent device reference' % (tag, ));
+                    if ':' == tag[-1]:
+                        self.handleError('Element screen attribute tag "%s" ends with separator' % (tag, ));
+                    if tag.find('::') >= 0:
+                        self.handleError('Element screen attribute tag "%s" contains double separator' % (tag, ));
             self.in_object = True
             self.have_bounds.append(False)
         elif 'group' == name:

src/emu/rendlay.cpp

@@ -2676,7 +2676,10 @@ layout_view::item::item(
 	// sanity checks
 	if (strcmp(itemnode.get_name(), "screen") == 0)
 	{
-		if (m_screen == nullptr)
+        char const *const tag(itemnode.get_attribute_string("tag", nullptr));
+        if (tag)
+            m_screen = dynamic_cast<screen_device *>(machine.root_device().subdevice(tag));
+		if (!m_screen)
 			throw layout_reference_error(util::string_format("invalid screen index %d", index));
 	}
 	else

src/mame/layout/model1io2.lay

@@ -18,10 +18,10 @@
 	</element>
 
 	<view name="Default">
-		<screen index="0">
+		<screen tag="ioboard:screen">
 			<bounds left="0" top="0" right="1" bottom="1" />
 		</screen>
-		<screen index="1">
+		<screen tag="screen">
 			<bounds left="0" top="0" right="4" bottom="3" />
 		</screen>
 	</view>
@@ -30,10 +30,10 @@
 		<backdrop element="background">
 			<bounds x="0" y="0" width="496" height="419" />
 		</backdrop>
-		<screen index="1">
+		<screen tag="screen">
 			<bounds left="0" top="0" right="496" bottom="384" />
 		</screen>
-		<screen index="0">
+		<screen tag="ioboard:screen">
 			<bounds left="8" top="392" right="129" bottom="411" />
 		</screen>
 		<cpanel name="led_comm_err" element="led_red">

src/mame/layout/nbmj8688.lay

@@ -1,70 +1,70 @@
 <?xml version="1.0"?>
 <mamelayout version="2">
 	<view name="Main Screen Standard (4:3)">
-		<screen index="0">
+		<screen tag="screen">
 			<bounds left="0" top="0" right="4" bottom="3" />
 		</screen>
 	</view>
 
 	<view name="LCD0 Standard (15:3)">
-		<screen index="1">
+		<screen tag="lcd0">
 			<bounds left="0" top="0" right="15" bottom="3" />
 		</screen>
 	</view>
 
 	<view name="LCD1 Standard (15:3)">
-		<screen index="2">
+		<screen tag="lcd1">
 			<bounds left="0" top="0" right="15" bottom="3" />
 		</screen>
 	</view>
 
 	<view name="Main Screen Pixel Aspect (~scr0nativexaspect~:~scr0nativeyaspect~)">
-		<screen index="0">
+		<screen tag="screen">
 			<bounds left="0" top="0" right="~scr0width~" bottom="~scr0height~" />
 		</screen>
 	</view>
 
 	<view name="LCD0 Pixel Aspect (~scr1nativexaspect~:~scr1nativeyaspect~)">
-		<screen index="1">
+		<screen tag="lcd0">
 			<bounds left="0" top="0" right="~scr1width~" bottom="~scr1height~" />
 		</screen>
 	</view>
 
 	<view name="LCD1 Pixel Aspect (~scr2nativexaspect~:~scr2nativeyaspect~)">
-		<screen index="2">
+		<screen tag="lcd1">
 			<bounds left="0" top="0" right="~scr2width~" bottom="~scr2height~" />
 		</screen>
 	</view>
 
 	<view name="Triple">
-		<screen index="0">
+		<screen tag="screen">
 			<bounds x="0" y="3" width="15" height="11.25" />
 		</screen>
-		<screen index="1">
+		<screen tag="lcd0">
 			<bounds x="0" y="14.25" width="15" height="3" />
 			<orientation rotate="180" />
 		</screen>
-		<screen index="2">
+		<screen tag="lcd1">
 			<bounds x="0" y="0" width="15" height="3" />
 		</screen>
 	</view>
 
 	<view name="Player 1">
-		<screen index="0">
+		<screen tag="screen">
 			<bounds x="0" y="3" width="15" height="11.25" />
 		</screen>
-		<screen index="1">
+		<screen tag="lcd0">
 			<bounds x="0" y="14.25" width="15" height="3" />
 			<orientation rotate="180" />
 		</screen>
 	</view>
 
 	<view name="Player 2">
-		<screen index="0">
+		<screen tag="screen">
 			<bounds x="0" y="3" width="15" height="11.25" />
 			<orientation rotate="180" />
 		</screen>
-		<screen index="2">
+		<screen tag="lcd1">
 			<bounds x="0" y="14.25" width="15" height="3" />
 			<orientation rotate="180" />
 		</screen>