add metadata

docs/namespace_config_spec.md

@@ -56,6 +56,7 @@ The configuration language has the following keywords:
 * `type`
 * `this`
 * `ctx`
+* `id`
 
 ### Operators
 
@@ -78,6 +79,7 @@ The following character sequences represent miscelanious operators:
 | `=>` | `view(ctx) => foo(ctx)` | Function definition token. In the example, `view` is true if `foo` is true |
 | `.` | `this.x` | Property traversal token |
 | `:` | `relation: type` | Relation/type separator token |
+| `=` | `id = 123` | Metadata assignment token |
 
 ## Statements
 
@@ -88,19 +90,19 @@ each namespace. Each `type` consists of relation declarations and permission
 declarations.
 
 ```ebnf
-TypeDecl        = "type" identifier "{" [ TypeSpec ] "}" .
+TypeDecl        = "type" identifier "(" Metadata ")" "{" [ TypeSpec ] "}" .
+Metadata        = "id" "=" digit .
 TypeSpec        = { RelationDecl | PermissionDefn } .
 ```
 
-
 #### Example
 
 The following declares a type *user* that is never the object in any
 relation. It can, however, be the subject of a relation, the relation being
 declared on some other type.
 
 ```typescript
-type user {}
+type user(id = 123) {}
 ```
 
 ### Relation declaration
@@ -119,9 +121,9 @@ The following declares a type *document* has three relations: *owners* and
 *viewers*, both of which have *users* as subjects. Additionally, the relation
 *parent* has type *file*.
 ```typescript
-type file {}
+type file(id=2) {}
 
-type document {
+type document(id = 31) {
   parent: file
   owners: user[]
   viewers: user[]
@@ -193,8 +195,8 @@ flowchart LR
 
   subgraph TypeSpec
     direction LR
-    A2(" ") --> RelationDecl
-    A2(" ") --> PermissionDefn
+    A2{" "} --> RelationDecl
+    A2 --> PermissionDefn
     PermissionDefn --> X2(((" ")))
     RelationDecl --> X2(((" ")))
   end
@@ -214,9 +216,9 @@ flowchart LR
 ## Examples
 
 ```typescript
-type user {}
+type user(id=1) {}
 
-type file {
+type file(id=2) {
   parent: file
   viewers: user[]
   owners: user[]
@@ -232,9 +234,9 @@ type file {
 ### Alternative set membership syntax:
 
 ```typescript
-type user {}
+type user(id=1) {}
 
-type file {
+type file(id=2) {
   parent: file
   viewers: user[]
   owners: user[]
@@ -245,4 +247,33 @@ type file {
   edit(ctx) => this.owners.contains(ctx.subject)
   rename(ctx) => this.siblings.exists(sibling, sibling.edit(ctx))
 }
+```
+
+### Alternative full TypeScript syntax
+
+```typescript
+class user {
+  static id = 1
+}
+
+class file {
+  static id = 2
+
+  parent: file
+  viewers: user[]
+  owners: user[]
+  siblings: file[]
+
+  isViewer = (ctx) => this.viewers.contains(ctx.subject)
+  view = (ctx) =>
+    this.viewers.contains(ctx.subject) ||
+      this.owners.contains(ctx.subject) ||
+      this.parent.view(ctx)
+
+  edit = (ctx) =>
+    this.owners.contains(ctx.subject)
+
+  rename = (ctx) =>
+    this.siblings.exists(sibling, sibling.edit(ctx))
+}
 ```