[elpa] externals/triples 5e8abd2989 01/19: Initial commit of triples module.

[ELPA Syncer]

branch: externals/triples
commit 5e8abd2989f4f9fb3e93e99269b95a51367e1e78
Author: Andrew Hyatt <ahyatt@gmail.com>
Commit: Andrew Hyatt <ahyatt@gmail.com>

    Initial commit of triples module.
---
 .gitignore      |   1 +
 COPYING         | 339 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 README.org      |  79 +++++++++++++
 triples-test.el | 193 ++++++++++++++++++++++++++++++++
 triples.el      | 330 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 942 insertions(+)

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000000..016d3b1692
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+*.elc
\ No newline at end of file
diff --git a/COPYING b/COPYING
new file mode 100644
index 0000000000..ecbc059373
--- /dev/null
+++ b/COPYING
@@ -0,0 +1,339 @@
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diff --git a/README.org b/README.org
new file mode 100644
index 0000000000..214e4f663f
--- /dev/null
+++ b/README.org
@@ -0,0 +1,79 @@
+#+TITLE: Triples
+
+The =triples= module is a standard database module designed for use in other 
emacs modules.  It works with the =sqlite= module, and provides a simple way of 
storing entities and their associated schema.  The triples module is well 
suited to graph-like applications, where links between entities are important.  
The module has wrappers for most common operations, but it is anticipated that 
occasionally client modules would need to make their own =sqlite= calls.  Many 
database can be handled [...]
+
+* Maturity
+This module is very new should be considered alpha quality.
+
+While it has basic functionality, there are significant parts, such as a 
querying language, that are missing.  Whether anyone needs such parts will 
determine the priority in which they get built.
+
+* Types and Schema
+=triples= employs a design in which each entity can be a member of many 
/types/, and each /type/ has multiple /properties/.  The properties that a type 
has is defined by /schema/.  Let's take an example:
+
+#+begin_src emacs-lisp
+;; We assume a database called db has already been set up.
+(triples-add-schema db 'person
+       '(name :base/unique t :base/type string)
+       '(age :base/unique t :base/type integer))
+(triples-add-schema db 'employee
+       '(id :base/unique t :base/type integer)
+       '(manager :base/unique t)
+       '(reportees :base/virtual-reversed employee/manager))
+#+end_src
+
+This adds a type called =person=, which can be set on any entity.  There's 
another type called =employee=, which can also be set, independently of other 
types.  This schema is stored in the database itself, so the database can 
function properly regardless on what elisp has been loaded.  The schema can be 
redefined multiple times without any issues.
+
+The =person= has 2 properties, =name=, and =age=.  They are both marked as 
unique, so they take a single value, not a list.  If =:base/unique= was not 
true, the value would be a list.  We also specify what type it is, which can be 
any elisp type.  =employee= is similarly constructed, but has an interesting 
property, =reportees=, which is a =base/virtual-reversed= property, meaning 
that it is supplied with values, but rather can get them from the reversed 
relation of =employee/manager=.
+
+We'll explore how these types are used can be used in the section after next.
+* The triples concept
+A triple is a unit of data consisting of a /subject/, a /predicate/, an 
/object/, and, optionally, internal metadata about the unit.  The triple can be 
thought of as a link between the subject and object via the predicate.
+
+Let's say that, as in the example above, we want to store someone's name.  The 
triples would be a /subject/ that uniquely identifies the person, a /predicate/ 
that indicates the link between subject and object is about a name, and the 
object, which is the name value.
+
+The object can become the subject, and this explains how the 
=base/virtual-reversed= predicate works.   If Bob is the manager of Alice, then 
there could be a triple with Alice as the subject, =manager= as the predicate, 
and Bob as the object.  But we can also find the reversed links, and ask who 
all are all the people that Bob manages.  In this case, Bob is the subject, and 
Alice is the object.  However, we don't actually need to store this information 
and try to keep it in sync, we can  [...]
+* Setting and retrieving
+A subject can be set all at once (everything about the subject), or dealt with 
per-type.  For example, the following are equivalent:
+
+#+begin_src emacs-lisp
+(triples-delete-subject db "alice")
+(triples-set-type db "alice" 'person :name "Alice Aardvark" :age 41)
+(triples-set-type db "alice" 'employee :id 1901 :manager "bob")
+#+end_src
+
+#+begin_src emacs-lisp
+(triples-set-subject db "alice" '(person :name "Alice Aardvark" :age 41)
+                     '(employee :id 1901 :manager "bob"))
+#+end_src
+
+In the second, the setting of the entire subject implies deleting everything 
previously associated with it.
+
+Here is how the data is retrieved:
+
+#+begin_src emacs-lisp
+(triples-get-subject db "alice")
+#+end_src
+Which returns, assuming we have "catherine" and "dennis" who have "alice" as 
their =employee/manager=: 
+#+begin_src emacs-lisp
+'(:person/name "Alice Aardvark" :person/age 41 :employee/id 1901 
:employee/manager "bob" :employee/reportees '("catherine" "dennis"))
+#+end_src
+
+Or,
+#+begin_src emacs-lisp
+(triples-get-type db "alice" 'employee)
+#+end_src
+Which returns
+#+begin_src emacs-lisp
+'(:manager "bob" :reportees '("catherine" "dennis"))
+#+end_src
+
+There are other useful functions, including:
+- =triples-get-types=, which gets all the types a subject has,
+- =triples-delete-subject=, which deletes all data associated with a subject,
+- =triples-with-predicate=, gets all triples that is about a specific property,
+- =triples-with-predicate-object=, get all subjects whose predicate is equal 
to /object/,
+- =triples-subjects-of-type=, get all subjects which have a particular type.
+* Preciate, with type and without
+Sometimes the triples library will require predicates that are without type, 
and sometimes with type, or "combined predicates".  The rule is that if the 
type is already specified in the function, it does not need to be respecified.  
If the type is not specified, it is included in the combined predicate.
+
+When returning data, if data is from just one type, the type is not returned 
in the returned predicates.  If the data is from multiple types, the type is 
returned as combined predicates.
diff --git a/triples-test.el b/triples-test.el
new file mode 100644
index 0000000000..9689a9e65e
--- /dev/null
+++ b/triples-test.el
@@ -0,0 +1,193 @@
+;;; triples-test.el --- Tests for triples module.
+(require 'triples)
+(require 'seq)
+
+;;; Code:
+
+(defvar triples-test-db-file nil
+  "The database file used in a test. This is defined so we can
+easily debug into it.")
+
+(defmacro triples-test-with-temp-db (&rest body)
+  (declare (indent 0) (debug t))
+  `(let ((db-file (make-temp-file "triples-test")))
+     (unwind-protect
+         (progn 
+           (let ((db (triples-connect db-file)))
+             (setq triples-test-db-file db-file)
+             ,@body))
+       (delete-file db-file))))
+
+(defun triples-test-connect-db ()
+  (interactive)
+  (defvar sql-database)
+  (let ((sql-database triples-test-db-file))
+    (sql-sqlite (format "*schema test db SQL %s*" triples-test-db-file))))
+
+(defun triples-test-op-equals (result target)
+  (and (equal (car result) (car target))
+       (seq-set-equal-p (cdr result) (cdr target) #'equal)))
+
+(ert-deftest triples-add-schema-op ()
+  (should (triples-test-op-equals
+           (triples--add-schema-op
+            'named
+            '(name :base/unique t)
+            '(locale :base/unique t)
+            'alternate-names
+            '(nicknames :base/unique nil))
+           '(replace-subject
+             .
+             ((named base/type schema)
+              (named schema/property name)
+              (named/name base/unique t)
+              (named schema/property locale)
+              (named/locale base/unique t)
+              (named schema/property alternate-names)
+              (named schema/property nicknames))))))
+
+(ert-deftest triples-schema-crud ()
+  (triples-test-with-temp-db
+    (triples-add-schema db 'named
+                        '(name :base/unique t) 'alternate-names)
+    (should (equal '(:base/unique t)
+           (triples-properties-for-predicate db 'named/name)))
+    (should (equal
+             '(name alternate-names)
+             (triples-predicates-for-type db 'named)))))
+
+(ert-deftest triples-properties-for-predicate ()
+  (triples-test-with-temp-db
+    (triples-add-schema db 'named
+                        '(name :base/unique t)
+                        'alternate-names)
+    (should (equal '(:base/unique t)
+                    (triples-properties-for-predicate db 'named/name)))
+    (should-not (triples-properties-for-predicate db 'foo/bar))))
+
+(ert-deftest triples-set-type ()
+  (should (triples-test-op-equals
+           (triples--set-type-op "Bert" 'named
+                                 '(:name "Bertholomew The Second"
+                                         :alias ("Bert" "Berty")))
+           '(replace-subject-type
+             .
+             (("Bert" base/type named)
+              ("Bert" named/name "Bertholomew The Second")
+              ("Bert" named/alias "Bert" (:index 0))
+              ("Bert" named/alias "Berty" (:index 1)))))))
+
+(ert-deftest triples-schema-compliant ()
+  (triples-test-with-temp-db
+    (triples-add-schema db 'named
+                        '(name :base/unique t :base/type string)
+                        'alternate-names)
+    (triples-set-type db "foo" 'named :name "name")
+    (should (triples-verify-schema-compliant db '(("foo" named/name "bar"))))
+    (should-error (triples-verify-schema-compliant db '(("foo" named/name 5))))
+    (should-error (triples-verify-schema-compliant db '(("foo" named/name 
"bar" (:index 0)))))
+    (should (triples-verify-schema-compliant db '(("foo" named/alternate-names 
"bar" (:index 0)))))))
+
+(ert-deftest triples-crud ()
+  (triples-test-with-temp-db
+   (triples-add-schema db 'named
+                       '(name :unique t)
+                       'alias)
+   (triples-set-type db "foo" 'named :name "Name" :alias '("alias1" "alias2"))
+   (should (equal '(:name "Name" :alias ("alias1" "alias2"))
+                  (triples-get-type db "foo" 'named)))
+   (should (equal (triples-get-types db "foo") '(named)))
+   (should-not (triples-get-type db "bar" 'named))
+   (should-not (triples-get-types db "bar"))
+   (should (equal '(named) (triples-get-types db "foo")))
+   (triples-remove-type db "foo" 'named)
+   (should-not (triples-get-types db "foo"))))
+
+(ert-deftest triples-crud-all ()
+  (triples-test-with-temp-db
+    (triples-add-schema db 'named
+                        '(name :unique t))
+    (triples-add-schema db 'positioned '(position :unique t))
+    (should-not (triples-get-subject db "foo"))
+    (triples-set-subject db "foo"
+                         '(named :name "bar")
+                         '(positioned :position "right behind you"))
+    (should (equal '(:named/name "bar" :positioned/position "right behind you")
+                   (triples-get-subject db "foo")))
+    (triples-delete-subject db "foo")
+    (should-not (triples-get-subject db "foo"))))
+
+(ert-deftest triples-reversed ()
+  (triples-test-with-temp-db
+   (triples-add-schema db 'named
+                       '(name :unique t)
+                       '(locale :unique t))
+   (triples-add-schema db 'locale
+                       '(used-in-name :base/virtual-reversed named/locale))
+   (triples-set-type db "en/US" 'locale nil)
+   (should-not (triples-get-type db "en/US" 'locale))
+   (triples-set-type db "foo" 'named :name "foo" :locale "en/US")
+   (should (equal '(:used-in-name ("foo"))
+                  (triples-get-type db "en/US" 'locale)))
+   (should-error (triples-set-type db "en/US" 'locale :used-in-name 
'("bar")))))
+
+(ert-deftest triples-with-preciate-object ()
+  (triples-test-with-temp-db
+   (triples-add-schema db 'named '(name))
+   (should-not (triples-search db 'named/name "Fred"))
+   (triples-set-type db "foo" 'named :name "My Name Is Fred Foo")
+   (triples-set-type db "bar" 'named :name "My Name Is Betty Bar")
+   (should (equal
+            '(("foo" named/name "My Name Is Fred Foo" nil))
+            (triples-search db 'named/name "Fred")))))
+
+(ert-deftest triples-with-predicate ()
+  (triples-test-with-temp-db
+   (triples-add-schema db 'named '(name))
+   (should-not (triples-with-predicate db :named/name))
+   (triples-set-type db "foo" 'named :name "My Name Is Fred Foo")
+   (triples-set-type db "bar" 'named :name "My Name Is Betty Bar")
+   (should (equal
+            '(("bar" named/name "My Name Is Betty Bar" nil)
+              ("foo" named/name "My Name Is Fred Foo" nil))
+            (sort (triples-with-predicate db :named/name)
+                  (lambda (a b)
+                    (string< (car a) (car b))))))))
+
+(ert-deftest triples-subjects-of-type ()
+  (triples-test-with-temp-db
+   (triples-add-schema db 'named '(name))
+   (should-not (triples-subjects-of-type db 'named))
+   (triples-set-type db "foo" 'named :name "My Name Is Fred Foo")
+   (triples-set-type db "bar" 'named :name "My Name Is Betty Bar")
+   (should (seq-set-equal-p '("foo" "bar")
+                            (triples-subjects-of-type db 'named)))))
+
+(ert-deftest triples-readme ()
+  (triples-test-with-temp-db
+   (triples-add-schema db 'person
+       '(name :base/unique t :base/type string)
+       '(age :base/unique t :base/type integer))
+   (triples-add-schema db 'employee
+       '(id :base/unique t :base/type integer)
+       '(manager :base/unique t)
+       '(reportees :base/virtual-reversed employee/manager))
+   ;; Set up catherine and dennis
+  (triples-set-type db "catherine" 'employee :manager "alice")
+  (triples-set-type db "dennis" 'employee :manager "alice")
+  (triples-delete-subject db "alice")
+  (triples-set-type db "alice" 'person :name "Alice Aardvark" :age 41)
+  (triples-set-type db "alice" 'employee :id 1901 :manager "bob")
+  (should (equal (triples-get-subject db "alice")
+                 '(:person/name "Alice Aardvark" :person/age 41 :employee/id 
1901
+                                :employee/manager "bob" :employee/reportees 
("catherine" "dennis"))))
+  (triples-set-subject db "alice" '(person :name "Alice Aardvark" :age 41)
+                       '(employee :id 1901 :manager "bob"))
+  (should (equal (triples-get-subject db "alice")
+                 '(:person/name "Alice Aardvark" :person/age 41 :employee/id 
1901
+                                :employee/manager "bob" :employee/reportees 
("catherine" "dennis"))))))
+
+
+(provide 'triples-test)
+
+;;; triples-test.el ends here
diff --git a/triples.el b/triples.el
new file mode 100644
index 0000000000..e8c95dd75e
--- /dev/null
+++ b/triples.el
@@ -0,0 +1,330 @@
+;;; triples.el --- This package provides a triple-based database, as well as
+;;; functions to store, retrieve, and modify the information it contains.
+
+;; Copyright (c) 2022  Free Software Foundation, Inc.
+
+;; Author: Andrew Hyatt <ahyatt@gmail.com>
+;; Homepage: https://github.com/ahyatt/triples
+;; Keywords: triples, kg
+;; Version: 0.0
+;; This program is free software; you can redistribute it and/or
+;; modify it under the terms of the GNU General Public License as
+;; published by the Free Software Foundation; either version 2 of the
+;; License, or (at your option) any later version.
+;;
+;; This program is distributed in the hope that it will be useful, but
+;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;; General Public License for more details.
+;;
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;; Triples is a library implementing a data storage based on the idea of
+;; triples: subject, predicate, objects, plus some extra metadata. This data
+;; structure provides a way to store data according to an extensible schema, 
and
+;; provide an API offering two-way links between all information stored.
+
+(require 'cl-macs)
+(require 'emacsql)
+(require 'seq)
+
+(defun triples-connect (file)
+  "Connect to the database and make sure it is populated."
+  (let* ((db (emacsql-sqlite3 file))
+         (triple-table-exists
+          (emacsql db [:select name
+                       :from sqlite_master
+                       :where (= type table) :and (= name 'triples)])))
+    (unless triple-table-exists
+      (emacsql db [:create-table triples ([(subject text :not-null)
+                                               (predicate text :not-null)
+                                               (object :not-null)
+                                               (properties)])])
+      (emacsql db [:create-index subject_idx :on triples [subject]])
+      (emacsql db [:create-index subject_predicate_idx :on triples [subject 
predicate]])
+      (emacsql db [:create-index predicate_object_idx :on triples [predicate 
object]]))
+    db))
+
+(defun triples--ensure-property-val (vec)
+  "Return a VEC has 4 elements."
+  (if (= (length vec) 4)
+      vec
+    (vconcat vec '(nil))))
+
+(defun triples--subjects (triples)
+  "Return all unique subjects in TRIPLES."
+  (seq-uniq (mapcar #'car triples)))
+
+(defun triples--group-by-subjects (triples)
+  "Return an alist of subject to TRIPLES with that subject."
+  (let ((subj-to-triples (make-hash-table :test #'equal)))
+    (dolist (triple triples)
+      (puthash (car triple)
+               (cons triple (gethash (car triple) subj-to-triples))
+               subj-to-triples))
+    (cl-loop for k being the hash-keys of subj-to-triples using (hash-values v)
+             collect (cons k v))))
+
+(defun triples--decolon (sym)
+  "Remove colon from SYM."
+  (intern (string-replace ":" "" (format "%s" sym))))
+
+(defun triples--encolon (sym)
+  "Add a colon to SYM."
+  (intern (format ":%s" sym)))
+
+(defun triples--add (db op)
+  "Perform OP on DB."
+  (pcase (car op)
+      ('replace-subject
+       (mapc
+        (lambda (sub)
+          (emacsql db [:delete :from triples :where (= subject $s1)] sub))
+        (triples--subjects (cdr op))))
+      ('replace-subject-type
+       (mapc (lambda (sub-triples)
+               (mapc (lambda (type)
+                       ;; We have to ignore base, which keeps type information 
in general.
+                       (unless (eq type 'base)
+                         (emacsql db [:delete :from triples :where (= subject 
$s1)
+                                      :and (like predicate $r2)]
+                                  (car sub-triples) (format "%s/%%" type))))
+                     (seq-uniq
+                      (mapcar #'car (mapcar 
#'triples--combined-to-type-and-prop
+                                                     (mapcar #'cl-second (cdr 
sub-triples)))))))
+             (triples--group-by-subjects (cdr op)))))
+    (mapc (lambda (triple)
+            (emacsql db [:insert :into triples
+                         :values $v1] (triples--ensure-property-val
+                                       (apply #'vector triple))))
+          (cdr op)))
+
+(defun triples-properties-for-predicate (db cpred)
+  "Return the properties for combined predicate CPRED as a plist."
+  (mapcan (lambda (row)
+            (list (intern (format ":%s" (nth 1 row))) (nth 2 row)))
+          (emacsql db [:select * :from triples :where (= subject $s1)] cpred)))
+
+(defun triples-predicates-for-type (db type)
+  "Return all predicates defined for TYPE in DB."
+  (mapcar #'car
+          (emacsql db [:select object :from triples :where (= subject $s1)
+                       :and (= predicate 'schema/property)] type)))
+
+(defun triples-verify-schema-compliant (db triples)
+  "Error if TRIPLES is not compliant with schema in DB."
+  (mapc (lambda (triple)
+          (pcase-let ((`(,type . ,prop) (triples--combined-to-type-and-prop 
(nth 1 triple))))
+            (unless (or (eq type 'base) 
+                        (emacsql db [:select * :from triples :where (= subject 
$s1)
+                                     :and (= predicate 'schema/property) :and 
(= object $s2)]
+                                 type prop))
+              (error "Property %s not found in schema." (nth 1 triple)))))
+        triples)
+  (mapc (lambda (triple)
+          (triples--plist-mapc (lambda (pred-prop val)
+                                 (let ((f (intern (format 
"triples-verify-%s-compliant"
+                                                          (triples--decolon 
pred-prop)))))
+                                 (if (fboundp f)
+                                     (funcall f val triple))))
+                             (triples-properties-for-predicate db (nth 1 
triple)))) triples))
+
+(defun triples-add-schema (db type &rest props)
+  "Add schema for TYPE and its PROPS to DB."
+  (triples--add db (apply #'triples--add-schema-op type props)))
+
+(defun triples--add-schema-op (type &rest props)
+  "Return the operation store schema for TYPE, with PROPS.
+PROPS is a list of either property symbols, or lists of
+properties of the type and the meta-properties associated with
+them."
+  (cons 'replace-subject
+        (cons `(,type base/type schema)
+              (cl-loop for p in props
+                       nconc
+                       (let* ((pname (if (symbolp p) p (car p)))
+                              (pprops (when (listp p) (cdr p)))
+                              (pcombined (intern (format "%s/%s" type pname))))
+                         (cons (list type 'schema/property pname)
+                               (seq-filter #'identity
+                                (triples--plist-mapcar
+                                   (lambda (k v)
+                                     ;; If V is nil, that's the default, so 
don't
+                                     ;; store anything.
+                                     (when v
+                                       (list pcombined (triples--decolon k) 
v)))
+                                   pprops))))))))
+
+(defun triples-set-type (db subject type &rest properties)
+  "Create operation to replace PROPERTIES for TYPE for SUBJECT in DB.
+PROPERTIES is a plist of properties, without TYPE prefixes."
+  (let ((op (triples--set-type-op subject type properties)))
+    (triples-verify-schema-compliant db (cdr op))
+    (triples--add db op)))
+
+(defun triples--set-type-op (subject type properties)
+  "Create operation to replace PROPERTIES for TYPE for SUBJECT.
+PROPERTIES is a plist of properties, without TYPE prefixes."
+  (cons 'replace-subject-type
+        (cons (list subject 'base/type type)
+              (triples--plist-mapcan
+               (lambda (prop v)
+                 (if (listp v)
+                     (cl-loop for e in v for i from 0
+                              collect
+                              (list subject
+                                    (triples--type-and-prop-to-combined type 
prop)
+                                    e
+                                    (list :index i)))
+                   (list (list subject (triples--type-and-prop-to-combined 
type prop) v))))
+               properties))))
+
+(defun triples-get-type (db subject type)
+  "From DB get data associated with TYPE for SUBJECT."
+  (let ((preds (make-hash-table :test #'equal)))
+    (mapc (lambda (db-triple)
+            (puthash (nth 1 db-triple)
+                     (cons (cons (nth 2 db-triple) (nth 3 db-triple))
+                           (gethash (nth 1 db-triple) preds))
+                     preds)) 
+          (emacsql db [:select * :from triples :where (= subject $s1)
+                       :and (like predicate $r2)] subject (format "%s/%%" 
type)))
+    (append
+     (cl-loop for k being the hash-keys of preds using (hash-values v)
+              nconc (list (triples--encolon (cdr 
(triples--combined-to-type-and-prop k)))
+                          (if (and (cdr v)
+                                   (plist-get (cdar v) :index))
+                              (mapcar #'car (sort v (lambda (a b)
+                                                      (< (plist-get (cdr a) 
:index)
+                                                         (plist-get (cdr b) 
:index)))))
+                            (caar v))))
+     (cl-loop for pred in (triples-predicates-for-type db type)
+              nconc
+              (let ((reversed-prop (plist-get
+                                    (triples-properties-for-predicate
+                                     db (triples--type-and-prop-to-combined 
type pred))
+                                    :base/virtual-reversed)))
+                (when reversed-prop
+                  (let ((result (emacsql db [:select subject :from triples 
:where (= object $s1)
+                                             :and (= predicate $s2)] subject 
reversed-prop)))
+                    (when result (cons (triples--encolon pred) (list (mapcar 
#'car result)))))))))))
+
+(defun triples-remove-type (db subject type)
+  "Remove TYPE for SUBJECT in DB, and all associated data."
+  (emacsql-with-transaction db
+    (emacsql db [:delete :from triples :where (= subject $s1)
+                 :and (= predicate 'base/type)] subject)
+    (emacsql db [:delete :from triples :where (= subject $s1)
+                 :and (like $r2)] subject (format "%s/%%" type))))
+
+(defun triples-get-types (db subject)
+  "From DB, get all types for SUBJECT."
+  (mapcar #'car (emacsql db [:select object :from triples :where (= subject 
$s1)
+                             :and (= predicate 'base/type)]
+                         subject)))
+
+(defun triples-get-subject (db subject)
+  "From DB return all properties for SUBJECT as a single plist."
+  (mapcan (lambda (type)
+            (triples--plist-mapcan
+             (lambda (k v)
+               (list (intern (format ":%s/%s" type (triples--decolon k))) v))
+             (triples-get-type db subject type)))
+          (triples-get-types db subject)))
+
+(defun triples-set-subject (db subject &rest type-vals-cons)
+  "From DB set properties of SUBJECT to TYPE-VALS-CONS data.
+TYPE-VALS-CONS is a list of conses, combining a type and a plist of values."
+  (emacsql-with-transaction db
+    (triples-delete-subject db subject)
+    (mapc (lambda (cons)
+            (apply #'triples-set-type db subject cons))
+          type-vals-cons)))
+
+(defun triples-delete-subject (db subject)
+  "Delete all data with DB as the subject."
+  (emacsql-with-transaction db
+    (emacsql db [:delete :from triples :where (= subject $s1)] subject)))
+
+(defun triples-search (db cpred text)
+  "Search DB for instances of combined property CPRED with TEXT."
+  (emacsql db [:select * :from triples :where (= predicate $i1)
+               :and (like object $r2)] (triples--decolon cpred)
+                       (format "%%%s%%" text)))
+
+(defun triples-with-predicate (db cpred)
+  "Return all triples in DB with CPRED as its combined predicate."
+  (emacsql db [:select * :from triples :where (= predicate $i1)] 
(triples--decolon cpred)))
+
+(defun triples-subjects-with-predicate-object (db cpred obj)
+  "Return all subjects in DB with CPRED equal to OBJ."
+  (emacsql db [:select subject :from triples :where (= predicate $i1) :and (= 
object $s2)]
+           (triples--decolon cpred) obj))
+
+(defun triples-subjects-of-type (db type)
+  "Return a list of all subjects with a particular TYPE in DB."
+  (mapcar #'car (triples-subjects-with-predicate-object db 'base/type type)))
+
+(defun triples--combined-to-type-and-prop (combined)
+  "Return cons of type and prop that form the COMBINED normal representation.
+This is something of form `:type/prop'."
+  (let ((s (split-string (format "%s" combined) "/")))
+    (cons (triples--decolon (nth 0 s)) (intern (nth 1 s)))))
+
+(defun triples--type-and-prop-to-combined (type prop)
+  (intern (format "%s/%s" (triples--decolon type) (triples--decolon prop))))
+
+(defun triples--plist-mapc (fn plist)
+  "Map FN over PLIST, for only side effects.
+FN must take two arguments: the key and the value."
+  (let ((plist-index plist))
+    (while plist-index
+      (let ((key (pop plist-index)))
+        (funcall fn key (pop plist-index))))))
+
+(defun triples--plist-mapcar (fn plist)
+  "Map FN over PLIST, returning an element for every property.
+FN must take two arguments: the key and the value."
+  (let ((plist-index plist)
+        (result))
+    (while plist-index
+      (let ((key (pop plist-index)))
+        (push (funcall fn key (pop plist-index)) result)))
+    (nreverse result)))
+
+(defun triples--plist-mapcan (fn plist)
+  "Map FN over PLIST, nconcing elements together.
+FN must take two arguments: the key and the value."
+  (let ((plist-index plist)
+        (result))
+    (while plist-index
+      (let ((key (pop plist-index)))
+        (setq result (nconc result (funcall fn key (pop plist-index))))))
+    result))
+
+;; Standard properties
+
+(defun triples-verify-base/unique-compliant (uniquep triple)
+  "Verify that TRIPLE has an index or not, based on UNIQUEP."
+  (if uniquep
+      (when (member :index (nth 3 triple))
+        (error "Invalid triple found: %s, violates base/unique, should be just 
one value" triple))
+    (unless (member :index (nth 3 triple))
+      (error "Invalid triple found: %s, violates base/unique, should be a list 
of values" triple))))
+
+(defun triples-verify-base/type-compliant (type triple)
+  "Verify that TRIPLE's object is of TYPE."
+  (unless (eq (type-of (nth 2 triple)) type)
+    (error "Triple %s has an object with the wrong type: expected type of %s 
but was %s"
+           triple type (type-of (nth 2 triple)))))
+
+(defun triples-verify-base/virtual-reversed-compliant (_ triple)
+  "Virtual reversed properties shouldn't be set manually, so are never 
compliant."
+  (error "Invalid triple found: %s, should not be setting a 
`base/virtual-reversed' property."
+         triple))
+
+(provide 'triples)
+
+;;; triples.el ends here