CLDR-17140 kbd: specify modifier matching

docs/ldml/tr35-keyboards.md

@@ -90,6 +90,9 @@ The LDML specification is divided into the following parts:
   * [Element: scanCodes](#Element_scanCodes)
   * [Element: layers](#Element_layers)
   * [Element: layer](#Element_layer)
+    * [Layer Modifier Components](#layer-modifier-components)
+    * [Modifier Left- and Right- keys](#modifier-left--and-right--keys)
+    * [Layer Modifier Matching](#layer-modifier-matching)
   * [Element: row](#Element_row)
   * [Element: variables](#Element_variables)
   * [Element: string](#element-string)
@@ -201,8 +204,6 @@ Keyboard use can be challenging for individuals with various types of disabiliti
 
 **Arrangement:** The relative position of the rectangles that represent keys, either physically or virtually. A hardware keyboard has a static arrangement while a touch keyboard may have a dynamic arrangement that changes per language and/or layer. While the arrangement of keys on a keyboard may be fixed, the mapping of those keys may vary.
 
-**Base character:** The character emitted by a particular key when no modifiers are active. In ISO terms, this is group 1, level 1.
-
 **Base character:** The character emitted by a particular key when no modifiers are active. In ISO 9995-1:2009 terms, this is Group 1, Level 1.
 
 **Core keys:** also known as “alphanumeric” section. The primary set of key values on a keyboard that are used for typing the target language of the keyboard. For example, the three rows of letters on a standard US QWERTY keyboard (QWERTYUIOP, ASDFGHJKL, ZXCVBNM) together with the most significant punctuation keys. Usually this equates to the minimal set of keys for a language as seen on mobile phone keyboards.
@@ -1358,7 +1359,7 @@ A `layer` element describes the configuration of keys on a particular layer of a
 **Syntax**
 
 ```xml
-<layer id="layerId" modifier="{Set of Modifier Combinations}">
+<layer id="layerId" modifiers="{Set of Modifier Combinations}">
     ...
 </layer>
 ```
@@ -1380,46 +1381,88 @@ _Attribute_ `id` (required for `touch`)
 >
 > Must match `[A-Za-z0-9][A-Za-z0-9-]*`
 
-_Attribute:_ `modifier` (required for `hardware`)
+_Attribute:_ `modifiers` (required for `hardware`)
 
 > This has two roles. It acts as an identifier for the `layer` element for hardware keyboards (in the absence of the id= element) and also provides the linkage from the hardware modifiers into the correct `layer`.
 >
-> To indicate that no modifiers apply, the reserved name of `none` is used.
-> The following modifier components can be used, separated by spaces.
-> Note that `L` or `R` indicates a left- or right- side modifier only (such as `altL`)
-> whereas `alt` indicates _either_ left or right alt key (that is, `altL` or `altR`). `ctrl` indicates either left or right ctrl key (that is, `ctrlL` or `ctrlR`).
-> `shift` also indicates either shift key. The left and right shift keys are not distinguishable in this specification.
->
-> If there is a layer with a modifier `alt`, there may not be another layer with `altL` or `altR`.  Similarly, if there is a layer with a modifier `ctrl`, there may not be a layer with `ctrlL` or `ctrlR`.
->
-> - `none` (no modifier, may not be combined with others)
-> - `alt`
-> - `altL`
-> - `altR`
-> - `caps`
-> - `ctrl`
-> - `ctrlL`
-> - `ctrlR`
-> - `shift`
->
-> Note that `alt` in this specification is referred to on some platforms as "opt" or "option".
->
-> Left- and right- side modifiers (such as `"altL ctrlR"` or `"altL altR"`) should not be used together in a single `modifier` attribute value.
->
-> For hardware layouts, the use of `@modifier` as an identifier for a layer is sufficient since it is always unique among the set of `layer` elements in a keyboard.
+> For hardware layouts, the use of `@modifiers` as an identifier for a layer is sufficient since it is always unique among the set of `layer` elements in each  `form`.
 >
 > The set of modifiers must match `(none|([A-Za-z0-9]+)( [A-Za-z0-9]+)*)`
 >
-> To share a layer between two modifier sets, the layer data must be duplicated.
+> To indicate that no modifiers apply, the reserved name of `none` is used.
+
+**Syntax**
+
+```xml
+<layer id="base"        modifiers="none">
+    <row keys="a" />
+</layer>
+
+<layer id="upper"       modifiers="shift">
+    <row keys="A" />
+</layer>
+
+<layer id="altgr"       modifiers="altR">
+    <row keys="a-umlaut" />
+</layer>
+
+<layer id="upper-altgr" modifiers="altR shift">
+    <row keys="A-umlaut" />
+</layer>
+```
+
+#### Layer Modifier Components
+
+ The following modifier components can be used, separated by spaces.
+
+ - `none` (no modifier)
+ - `alt`
+ - `altL`
+ - `altR`
+ - `caps`
+ - `ctrl`
+ - `ctrlL`
+ - `ctrlR`
+ - `shift`
+ - `other` (matches if no other layers match)
+
+1. `alt` in this specification is referred to on some platforms as "opt" or "option".
+
+2. `none` and `other` may not be combined with any other components.
+
+#### Modifier Left- and Right- keys
+
+1. `L` or `R` indicates a left- or right- side modifier only (such as `altL`)
+ whereas `alt` indicates _either_ left or right alt key (that is, `altL` or `altR`). `ctrl` indicates either left or right ctrl key (that is, `ctrlL` or `ctrlR`).
+
+2.  If there are any layers (in the same `form=`) with a modifier `alt`, there may not also be another layer with `altL` or `altR`.  Similarly, if there is a layer with a modifier `ctrl`, there may not be a layer with `ctrlL` or `ctrlR`.
+
+3. Left- and right- side modifiers may not be mixed together in a single `modifier` attribute value, so neither `altL ctrlR"` nor `altL altR` are allowed.
+
+4. `shift` indicates either shift key. The left and right shift keys are not distinguishable in this specification.
+
+#### Layer Modifier Matching
+
+Layers are matched exactly based on the modifier keys which are down. For example:
+
+- `none` as a modifier will only match if *all* of the keys `caps`, `alt`, `ctrl` and `shift` are up.
+
+- `alt` as a modifier will only match if either `alt` is down, *and* `caps`, `ctrl`, and `shift` are up.
+
+- `altL ctrl` as a modifier will only match if the left `alt` is down, either `ctrl` is down, *and* `shift` and `caps` are up.
+
+- `other` as a modifier will match if no other layers match.
+
+Multiple modifier sets may be separated by commas.  For example, `none, shift caps` will match either no modifiers *or* shift and caps.  `ctrlL altL, altR` will match either  left-control and left-alt, *or* right-alt.
+
+Keystrokes where there isn’t an explicitly matching layer, and where there is no layer with `other` specified, are ignored.
 
 * * *
 
 ### <a name="Element_row" href="#Element_row">Element: row</a>
 
 A `row` element describes the keys that are present in the row of a keyboard.
 
-
-
 **Syntax**
 
 ```xml

keyboards/3.0/fr-t-k0-azerty.xml

@@ -110,7 +110,7 @@
 
 	<layers formId="iso">
 		<!-- in DTD: required if conformsTo ≥ 41 -->
-		<layer modifier="none">
+		<layer modifiers="none">
 			<row
 				keys="super-2 amp e-grave double-quote apos open-paren hyphen e-acute underscore c-cedilla a-acute close-paren equal" />
 			<row keys="a z e r t y u i o p caret dollar" />
@@ -119,7 +119,7 @@
 			<row keys="space" />
 		</layer>
 
-		<layer modifier="shift">
+		<layer modifiers="shift">
 			<row keys="1 2 3 4 5 6 7 8 9 0 degree plus" />
 			<row keys="A Z E R T Y U I O P umlaut pound" />
 			<row keys="Q S D F G H J K L M percent micro" />

keyboards/3.0/ja-Latn.xml

@@ -13,14 +13,14 @@
 	</keys>
 
 	<layers formId="jis">
-		<layer modifier="none">
+		<layer modifiers="none">
 			<row keys="1 2 3 4 5 6 7 8 9 0 hyphen caret yen" />
 			<row keys="q w e r t y u i o p at open-square" />
 			<row keys="a s d f g h j k l semi-colon colon close-square" />
 			<row keys="z x c v b n m comma period slash underscore" />
 			<row keys="space"/>
 		</layer>
-		<layer modifier="shift">
+		<layer modifiers="shift">
 			<row keys="bang double-quote hash dollar percent amp apos open-paren close-paren 0 equal tilde pipe" /> <!-- 0 is repeated from "none" -->
 			<row keys="Q W E R T Y U I O P grave open-curly" />
 			<row keys="A S D F G H J K L plus asterisk close-curly" />

keyboards/3.0/mt-t-k0-47key.xml

@@ -44,31 +44,31 @@
 
     <!-- 47-key: MSA 100:2002, Appendix, figure A.1 -->
     <layers formId="us">
-        <layer modifier="none">
+        <layer modifiers="none">
             <row keys="c-tikka 1 2 3 4 5 6 7 8 9 0 hyphen equal" />
             <row keys="q w e r t y u i o p g-tikka h-maqtugha z-tikka" />
             <row keys="a s d f g h j k l semi-colon apos" />
             <row keys="z x c v b n m comma period slash" />
             <row keys="space" />
         </layer>
 
-        <layer modifier="shift">
+        <layer modifiers="shift">
             <row keys="C-tikka bang at euro dollar percent caret amp asterisk open-paren close-paren underscore plus" />
             <row keys="Q W E R T Y U I O P G-tikka H-maqtugha Z-tikka" />
             <row keys="A S D F G H J K L colon double-quote" />
             <row keys="Z X C V B N M open-angle close-angle question" />
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR">
+        <layer modifiers="altR">
             <row keys="grave gap gap pound gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap e-grave gap gap gap u-grave i-grave o-grave gap open-square close-square backslash" />
             <row keys="a-grave gap gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap gap gap gap gap gap gap gap gap" />
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR shift">
+        <layer modifiers="altR shift">
             <row keys="tilde gap gap gap gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap E-grave gap gap gap U-grave I-grave O-grave gap open-curly close-curly pipe" />
             <row keys="A-grave gap gap gap gap gap gap gap gap gap gap" />

keyboards/3.0/mt.xml

@@ -47,31 +47,31 @@
 
      <!-- 48-key -->
     <layers formId="iso">
-        <layer modifier="none">
+        <layer modifiers="none">
             <row keys="c-tikka 1 2 3 4 5 6 7 8 9 0 hyphen equal" />
             <row keys="q w e r t y u i o p g-tikka h-maqtugha" />
             <row keys="a s d f g h j k l semi-colon hash" />
             <row keys="z-tikka z x c v b n m comma period slash" />
             <row keys="space" />
         </layer>
 
-        <layer modifier="shift">
+        <layer modifiers="shift">
             <row keys="C-tikka bang double-quote euro dollar percent caret amp open-paren close-paren underscore plus" />
             <row keys="Q W E R T Y U I O P G-tikka H-maqtugha" />
             <row keys="A S D F G H J K L colon at tilde" />
             <row keys="Z-tikka Z X C V B N M open-angle close-angle question" />
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR">
+        <layer modifiers="altR">
             <row keys="grave gap gap pound gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap e-grave gap gap gap u-grave i-grave o-grave gap open-square close-square" />
             <row keys="a-grave gap gap gap gap gap gap gap gap gap gap gap" />
             <row keys="backslash gap gap gap gap gap gap gap gap gap gap" />
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR shift">
+        <layer modifiers="altR shift">
             <row keys="not gap gap gap gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap E-grave gap gap gap U-grave I-grave O-grave gap open-curly close-curly" />
             <row keys="A-grave gap gap gap gap gap gap gap gap gap gap gap" />

keyboards/3.0/pcm.xml

@@ -21,23 +21,23 @@
   </keys>
 
   <layers formId="iso">
-    <layer modifier="none">
+    <layer modifiers="none">
       <row keys="grave 1 2 3 4 5 6 7 8 9 0 hyphen equal" />
       <row keys="acute w e r t y u i o p open-square close-square" />
       <row keys="a s d f g h j k l odot edot slash" />
       <row keys="slash z c v b n m comma period semi-colon apos" />
       <row keys="space" />
     </layer>
 
-    <layer modifier="shift">
+    <layer modifiers="shift">
       <row keys="grave bang at hash dollar naira percent amp asterisk open-paren close-paren underscore plus" />
       <row keys="A S D F G H J K L Odot Edot question" />
       <row keys="A S D F G H J K L Odot Edot" />
       <row keys="question Z C V B N M open-angle close-angle colon double-quote" />
       <row keys="space" />
     </layer>
 
-    <layer modifier="caps">
+    <layer modifiers="caps">
       <row keys="backquote 1 2 3 4 5 6 7 8 9 0 hyphen equal" />
       <row keys="Q W E R T Y U I O P open-square close-square" />
       <row keys="A S D F G H J K L Odot Edot slash" />

keyboards/3.0/pt-t-k0-abnt2.xml

@@ -35,21 +35,21 @@
 		<key id="ordinal-masculine" output="º" />
 	</keys>
 	<layers formId="abnt2">
-		<layer modifier="none">
+		<layer modifiers="none">
 			<row keys="apos 1 2 3 4 5 6 7 8 9 0 hyphen equal" />
 			<row keys="q w e r t y u i o p d-acute open-square" />
 			<row keys="a s d f g h j k l c-cedilla d-tilde close-square" />
 			<row keys="backslash z x c v b n m comma period semi-colon slash" />
 			<row keys="space"/>
 		</layer>
-		<layer modifier="shift">
+		<layer modifiers="shift">
 			<row keys="double-quote bang at hash dollar percent d-umlaut amp asterisk open-paren close-paren underscore plus" />
 			<row keys="Q W E R T Y U I O P d-grave open-curly" />
 			<row keys="A S D F G H J K L C-cedilla d-tilde close-curly" />
 			<row keys="pipe Z X C V B N M open-angle close-angle colon question" />
 			<row keys="space"/>
 		</layer>
-		<layer modifier="altR">
+		<layer modifiers="altR">
 			<row keys="gap super-1 super-2 super-3 pound cent not gap gap gap gap gap section" />
 			<row keys="slash question degree gap gap gap gap gap gap gap gap ordinal-feminine" />
 			<row keys="gap gap gap gap gap gap gap gap gap gap gap ordinal-masculine" />

keyboards/dtd/ldmlKeyboard3.dtd

@@ -164,7 +164,7 @@ Please view the subcommittee page for the most recent information.
     <!--@TECHPREVIEW-->
 <!ATTLIST layer id NMTOKEN #IMPLIED >
     <!--@MATCH:any-->
-<!ATTLIST layer modifier NMTOKENS #IMPLIED >
+<!ATTLIST layer modifiers NMTOKENS #IMPLIED >
     <!--@MATCH:regex/(none|([A-Za-z0-9]+)( [A-Za-z0-9]+)*)-->
 
 <!ELEMENT row EMPTY >

keyboards/dtd/ldmlKeyboard3.xsd

@@ -304,7 +304,7 @@ Note: DTD @-annotations are not currently converted to .xsd. For full CLDR file
         <xs:element maxOccurs="unbounded" minOccurs="0" ref="special"/>
       </xs:sequence>
       <xs:attribute name="id" type="xs:NMTOKEN"/>
-      <xs:attribute name="modifier" type="xs:NMTOKENS"/>
+      <xs:attribute name="modifiers" type="xs:NMTOKENS"/>
     </xs:complexType>
   </xs:element>
 

tools/cldr-code/src/test/java/org/unicode/cldr/unittest/TestDtdData.java

@@ -760,7 +760,7 @@ public boolean isDistinguishingOld(DtdType dtdType, String elementName, String a
                 if (elementName.equals("keyboard3") && attribute.equals("locale")
                         || elementName.equals("layers") && attribute.equals("formId")
                         || elementName.equals("layers") && attribute.equals("minDeviceWidth")
-                        || elementName.equals("layer") && attribute.equals("modifier")
+                        || elementName.equals("layer") && attribute.equals("modifiers")
                         || elementName.equals("form") && attribute.equals("id")
                         || elementName.equals("key") && attribute.equals("id")
                         || elementName.equals("keyList") && attribute.equals("id")

tools/cldr-code/src/test/resources/org/unicode/cldr/tool/KeyboardFlatten/broken-import-missing.xml

@@ -45,31 +45,31 @@
     </keys>
 
     <layers formId="iso">
-        <layer modifier="none">
+        <layer modifiers="none">
             <row keys="c-tikka 1 2 3 4 5 6 7 8 9 0 minus equals" />
             <row keys="q w e r t y u i o p g-tikka h-maqtua" />
             <row keys="a s d f g h j k l semi-colon hash" />
             <row keys="z-tikka z x c v b n m comma period slash" />
             <row keys="space" />
         </layer>
 
-        <layer modifier="shift">
+        <layer modifiers="shift">
             <row keys="C-tikka bang double-quote euro dollar percent caret amp open-paren close-paren underscore plus" />
             <row keys="Q W E R T Y U I O P G-tikka H-maqtua" />
             <row keys="A S D F G H J K L colon at tilde" />
             <row keys="Z-tikka Z X C V B N M open-angle close-angle question" />
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR">
+        <layer modifiers="altR">
             <row keys="grave gap gap pound gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap e-grave gap gap gap u-grave i-grave o-grave gap open-square close-square" />
             <row keys="a-grave gap gap gap gap gap gap gap gap gap gap gap" />
             <row keys="backslash gap gap gap gap gap gap gap gap gap gap" />
             <row keys="space" />
         </layer>
 
-        <layer modifier="altR-shift">
+        <layer modifiers="altR shift">
             <row keys="not gap gap gap gap gap gap gap gap gap gap gap gap" />
             <row keys="gap gap E-grave gap gap gap U-grave I-grave O-grave gap open-curly close-curly" />
             <row keys="A-grave gap gap gap gap gap gap gap gap gap gap gap" />