add subject requests ("who?")

README.md

@@ -162,6 +162,40 @@ The syntax for a **role request** consists of:
 ( What | what ) is <subject> [ a / an / the ] <role> [ of / to / from / in ] [?]
 ```
 
+Verb subject request
+--------------------
+
+To request an array of subjects who can perform an action on an object:
+
+```js
+relations.repos('Who can pull from %s?', 'buffet', function (err, users) {
+  // users = ['Carlos']
+});
+```
+
+### Syntax
+
+```
+( Who | who ) can <verb> [ of / to / from / in ] <object> [?]
+```
+
+Role subject request
+--------------------
+
+To request an array of subjects who have a role for an object:
+
+```js
+relations.repos('Who is the owner of %s?', 'buffet', function (err, users) {
+  // users = ['Carlos']
+});
+```
+
+### Syntax
+
+```
+( Who | who ) can <verb> [ of / to / from / in ] <object> [?]
+```
+
 Revocation
 ----------
 
@@ -276,6 +310,24 @@ Respond to a role request and call `cb(err, /* array */ objects)` with the resul
 - subject
 - role
 
+### `verb-subject-request` (cmd, cb)
+
+Respond to a verb subject request and call `cb(err, /* array */ subjects)` with
+the result. `cmd` will be an object containing the properties:
+
+- ctx - context object
+- verb
+- object
+
+### `role-subject-request` (cmd, cb)
+
+Respond to a role subject request and call `cb(err, /* array */ subjects)` with
+the result. `cmd` will be an object containing the properties:
+
+- ctx - context object
+- role
+- object
+
 ### `reset` (cb)
 
 Reset the store, dumping all storage and structure, calling `cb(err)` when done.

parser.pegjs

@@ -4,7 +4,9 @@
 
 start
   = ret:(
-  RoleQuestion
+  RoleSubjectRequest
+  / VerbSubjectRequest
+  / RoleQuestion
   / RoleRequest
   / Declaration
   / VerbRequest
@@ -72,6 +74,24 @@ RoleRequest "role request"
     }
   }
 
+VerbSubjectRequest "verb subject request"
+  = "who can "i verb:Token Preposition? " " object:Token "?"? {
+    return {
+      type: "verb-subject-request",
+      object: object,
+      verb: verb
+    }
+  }
+
+RoleSubjectRequest "role subject request"
+  = "who "i Positive Quantifier? " " role:Token Preposition? " " object:Token "?"? {
+    return {
+      type: "role-subject-request",
+      object: object,
+      role: role
+    }
+  }
+
 Token "token"
   = NamedToken / UnnamedToken / Literal
 

stores/memory.js

@@ -74,4 +74,24 @@ store.on('role-request', function (cmd, cb) {
   cb(null, Object.keys(subject.objects).filter(function (k) {
     return subject.objects[k][cmd.role];
   }));
+});
+
+store.on('verb-subject-request', function (cmd, cb) {
+  contexts[cmd.ctx.name] || (contexts[cmd.ctx.name] = {});
+  cb(null, Object.keys(contexts[cmd.ctx.name]).filter(function (subject) {
+    subject = contexts[cmd.ctx.name][subject];
+    if (!subject.objects[cmd.object]) return false;
+    return Object.keys(subject.objects[cmd.object]).some(function (role) {
+      return ~cmd.ctx.verbs[cmd.verb].indexOf(role);
+    });
+  }));
+});
+
+store.on('role-subject-request', function (cmd, cb) {
+  contexts[cmd.ctx.name] || (contexts[cmd.ctx.name] = {});
+  cb(null, Object.keys(contexts[cmd.ctx.name]).filter(function (subject) {
+    subject = contexts[cmd.ctx.name][subject];
+    if (!subject.objects[cmd.object]) return false;
+    return subject.objects[cmd.object][cmd.role];
+  }));
 });