Adjusted grammar in spec to handle nullability token `?`.

docs/language/dartLangSpec.tex

Index: docs/language/dartLangSpec.tex
diff --git a/docs/language/dartLangSpec.tex b/docs/language/dartLangSpec.tex
index c1d9e6b06ac936769a15bcd52f42dcfcd577a356..9cda514a2a457fc6e9bd996ca289ae7302ba8df7 100644
--- a/docs/language/dartLangSpec.tex
+++ b/docs/language/dartLangSpec.tex
@@ -707,7 +707,7 @@ A {\em required formal parameter} may be specified in one of three ways:
 \end{itemize}
 
 \begin{grammar}
-{\bf normalFormalParameter:}functionSignature;
+{\bf normalFormalParameter:}functionSignature `?'?;
       fieldFormalParameter;
       simpleFormalParameter
  .
@@ -820,8 +820,20 @@ metadata \ABSTRACT{}?  \CLASS{} identifier typeParameters? (superclass mixins?)?
 metadata \ABSTRACT{}?  \CLASS{} mixinApplicationClass
     .
 
+{\bf classDenotation:}
+    className typeArguments?

[Lasse Reichstein Nielsen, 2017/05/30 10:52:30]

className is equivalent to typeName, so this could be
  typeName typeArguments?

Also, that means that type could be declared as

  type  ::= className `?'?


So, maybe rename className to typeName so:

type ::= typeName `?'?
typeName ::= type typeArguments?
type ::= qualified
typeList ::= (comma separated types)
typeNameList ::= (comma separated typeNames)

(I know that classDenotation *should* refer to a class, but that's not handled
at the syntactic level, it's just the name of a type).

+  .
+
+{\bf className:}
+    qualified
+  .
+
+{\bf classDenotationList:}
+      classDenotation (`,$\!\!$' classDenotation)*
+    .
+
 {\bf mixins:}
-  \WITH{} typeList
+  \WITH{} classDenotationList
   .
 
 {\bf classMemberDefinition:}declaration `{\escapegrammar ;}' ;
@@ -1438,7 +1450,7 @@ A {\em redirecting factory constructor} specifies a call to a constructor of ano
 
 \begin{grammar}
 {\bf redirectingFactoryConstructorSignature:}
-      \CONST{}? \FACTORY{} identifier (`{\escapegrammar .}' identifier)? formalParameterList `=' type (`{\escapegrammar .}' identifier)?
+      \CONST{}? \FACTORY{} identifier (`{\escapegrammar .}' identifier)? formalParameterList `=' classDenotation (`{\escapegrammar .}' identifier)?
     .
 \end{grammar}
 
@@ -1716,7 +1728,7 @@ It is a compile-time error to specify an \EXTENDS{} clause for class \code{Objec
 
 \begin{grammar}
 {\bf superclass:}
-      \EXTENDS{} type
+      \EXTENDS{} classDenotation
     .
 \end{grammar}
 
@@ -1857,8 +1869,8 @@ A class has a set of direct superinterfaces. This set includes the interface of
 
 \begin{grammar}
 {\bf interfaces:}
-      \IMPLEMENTS{} typeList
-    .
+    \IMPLEMENTS{} classDenotationList
+  .
 \end{grammar}
 
 \LMHash{}
@@ -2046,7 +2058,7 @@ A mixin may be applied to a superclass, yielding a new class. Mixin application
 	identifier typeParameters? `='  mixinApplication `{\escapegrammar ;}' .
 
 {\bf mixinApplication:}
-     type mixins interfaces?
+      classDenotation mixins interfaces?
     .
 \end{grammar}
 
@@ -2364,7 +2376,7 @@ An {\em expression} is a fragment of Dart code that can be evaluated at run time
       literal;
       identifier;
       newExpression;
-      \NEW{} type `\#' (`{\escapegrammar .}' identifier)?;
+      \NEW{} classDenotation `\#' (`{\escapegrammar .}' identifier)?;
       constObjectExpression;
       `(' expression `)'
     .
@@ -3287,8 +3299,8 @@ The {\em new expression} invokes a constructor (\ref{constructors}).
 
 \begin{grammar}
 {\bf newExpression:}
-\NEW{} type (`{\escapegrammar .}' identifier)? arguments
-.
+    \NEW{} classDenotation (`{\escapegrammar .}' identifier)? arguments
+  .
 \end{grammar}
 
 \LMHash{}
@@ -3405,8 +3417,8 @@ A {\em constant object expression} invokes a constant constructor (\ref{constant
 
 \begin{grammar}
 {\bf constObjectExpression:}
-\CONST{} type ('{\escapegrammar .}' identifier)? arguments
-.
+    \CONST{} classDenotation ('{\escapegrammar .}' identifier)? arguments

[Lasse Reichstein Nielsen, 2017/05/30 10:52:30]

' -> ` 
maybe?

+  .
 \end{grammar}
 
 \LMHash{}
@@ -7031,7 +7043,7 @@ Static type annotations are used in variable declarations (\ref{variables}) (inc
 
  \begin{grammar}
 {\bf type:}
-      typeName typeArguments?
+      typeName typeArguments? `?'?
     .
 
 {\bf typeName:}