Include optional leading bar for unions & directive locations. Merging and closing #323

Author: leebyron

spec/Appendix B -- Grammar Summary.md

@@ -228,7 +228,7 @@ InterfaceTypeDefinition : Description? interface Name Directives[Const]? FieldDe
 UnionTypeDefinition : Description? union Name Directives[Const]? = UnionMembers
 
 UnionMembers :
-  - NamedType
+  - `|`? NamedType
   - UnionMembers | NamedType
 
 EnumTypeDefinition : Description? enum Name Directives[Const]? { EnumValueDefinition+ }
@@ -240,7 +240,7 @@ InputObjectTypeDefinition : Description? input Name Directives[Const]? { InputVa
 DirectiveDefinition : Description? directive @ Name ArgumentsDefinition? on DirectiveLocations
 
 DirectiveLocations :
-  - DirectiveLocation
+  - `|`? DirectiveLocation
   - DirectiveLocations | DirectiveLocation
 
 DirectiveLocation : one of

spec/Section 3 -- Type System.md

@@ -943,7 +943,7 @@ Interface types have the potential to be invalid if incorrectly defined.
 UnionTypeDefinition : Description? union Name Directives[Const]? = UnionMembers
 
 UnionMembers :
-  - NamedType
+  - `|`? NamedType
   - UnionMembers | NamedType
 
 GraphQL Unions represent an object that could be one of a list of GraphQL
@@ -1007,6 +1007,15 @@ Instead, the query would be:
 }
 ```
 
+Union members may be defined with an optional leading `|` character to aid
+formatting when representing a longer list of possible types:
+
+```graphql example
+union SearchResult =
+  | Photo
+  | Person
+```
+
 **Result Coercion**
 
 The union type should have some way of determining which object a given result
@@ -1273,7 +1282,7 @@ a non-null input type as invalid.
 DirectiveDefinition : Description? directive @ Name ArgumentsDefinition? on DirectiveLocations
 
 DirectiveLocations :
-  - DirectiveLocation
+  - `|`? DirectiveLocation
   - DirectiveLocations | DirectiveLocation
 
 DirectiveLocation : one of
@@ -1307,6 +1316,16 @@ fragment SomeFragment on SomeType {
 }
 ```
 
+Directive locations may be defined with an optional leading `|` character to aid
+formatting when representing a longer list of possible locations:
+
+```graphql example
+directive @example on
+  | FIELD
+  | FRAGMENT_SPREAD
+  | INLINE_FRAGMENT
+```
+
 Directives can also be used to annotate the type system definition language
 as well, which is :