-
Notifications
You must be signed in to change notification settings - Fork 4
/
otypes.html
622 lines (572 loc) · 21.2 KB
/
otypes.html
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
<!-- 2021-06-16 Wed 16:52 -->
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<title><code>moo</code> 無 <i>otypes</i></title>
<meta name="generator" content="Org mode" />
<meta name="author" content="Brett Viren" />
<style type="text/css">
<!--/*--><![CDATA[/*><!--*/
.title { text-align: center;
margin-bottom: .2em; }
.subtitle { text-align: center;
font-size: medium;
font-weight: bold;
margin-top:0; }
.todo { font-family: monospace; color: red; }
.done { font-family: monospace; color: green; }
.priority { font-family: monospace; color: orange; }
.tag { background-color: #eee; font-family: monospace;
padding: 2px; font-size: 80%; font-weight: normal; }
.timestamp { color: #bebebe; }
.timestamp-kwd { color: #5f9ea0; }
.org-right { margin-left: auto; margin-right: 0px; text-align: right; }
.org-left { margin-left: 0px; margin-right: auto; text-align: left; }
.org-center { margin-left: auto; margin-right: auto; text-align: center; }
.underline { text-decoration: underline; }
#postamble p, #preamble p { font-size: 90%; margin: .2em; }
p.verse { margin-left: 3%; }
pre {
border: 1px solid #ccc;
box-shadow: 3px 3px 3px #eee;
padding: 8pt;
font-family: monospace;
overflow: auto;
margin: 1.2em;
}
pre.src {
position: relative;
overflow: auto;
padding-top: 1.2em;
}
pre.src:before {
display: none;
position: absolute;
background-color: white;
top: -10px;
right: 10px;
padding: 3px;
border: 1px solid black;
}
pre.src:hover:before { display: inline; margin-top: 14px;}
/* Languages per Org manual */
pre.src-asymptote:before { content: 'Asymptote'; }
pre.src-awk:before { content: 'Awk'; }
pre.src-C:before { content: 'C'; }
/* pre.src-C++ doesn't work in CSS */
pre.src-clojure:before { content: 'Clojure'; }
pre.src-css:before { content: 'CSS'; }
pre.src-D:before { content: 'D'; }
pre.src-ditaa:before { content: 'ditaa'; }
pre.src-dot:before { content: 'Graphviz'; }
pre.src-calc:before { content: 'Emacs Calc'; }
pre.src-emacs-lisp:before { content: 'Emacs Lisp'; }
pre.src-fortran:before { content: 'Fortran'; }
pre.src-gnuplot:before { content: 'gnuplot'; }
pre.src-haskell:before { content: 'Haskell'; }
pre.src-hledger:before { content: 'hledger'; }
pre.src-java:before { content: 'Java'; }
pre.src-js:before { content: 'Javascript'; }
pre.src-latex:before { content: 'LaTeX'; }
pre.src-ledger:before { content: 'Ledger'; }
pre.src-lisp:before { content: 'Lisp'; }
pre.src-lilypond:before { content: 'Lilypond'; }
pre.src-lua:before { content: 'Lua'; }
pre.src-matlab:before { content: 'MATLAB'; }
pre.src-mscgen:before { content: 'Mscgen'; }
pre.src-ocaml:before { content: 'Objective Caml'; }
pre.src-octave:before { content: 'Octave'; }
pre.src-org:before { content: 'Org mode'; }
pre.src-oz:before { content: 'OZ'; }
pre.src-plantuml:before { content: 'Plantuml'; }
pre.src-processing:before { content: 'Processing.js'; }
pre.src-python:before { content: 'Python'; }
pre.src-R:before { content: 'R'; }
pre.src-ruby:before { content: 'Ruby'; }
pre.src-sass:before { content: 'Sass'; }
pre.src-scheme:before { content: 'Scheme'; }
pre.src-screen:before { content: 'Gnu Screen'; }
pre.src-sed:before { content: 'Sed'; }
pre.src-sh:before { content: 'shell'; }
pre.src-sql:before { content: 'SQL'; }
pre.src-sqlite:before { content: 'SQLite'; }
/* additional languages in org.el's org-babel-load-languages alist */
pre.src-forth:before { content: 'Forth'; }
pre.src-io:before { content: 'IO'; }
pre.src-J:before { content: 'J'; }
pre.src-makefile:before { content: 'Makefile'; }
pre.src-maxima:before { content: 'Maxima'; }
pre.src-perl:before { content: 'Perl'; }
pre.src-picolisp:before { content: 'Pico Lisp'; }
pre.src-scala:before { content: 'Scala'; }
pre.src-shell:before { content: 'Shell Script'; }
pre.src-ebnf2ps:before { content: 'ebfn2ps'; }
/* additional language identifiers per "defun org-babel-execute"
in ob-*.el */
pre.src-cpp:before { content: 'C++'; }
pre.src-abc:before { content: 'ABC'; }
pre.src-coq:before { content: 'Coq'; }
pre.src-groovy:before { content: 'Groovy'; }
/* additional language identifiers from org-babel-shell-names in
ob-shell.el: ob-shell is the only babel language using a lambda to put
the execution function name together. */
pre.src-bash:before { content: 'bash'; }
pre.src-csh:before { content: 'csh'; }
pre.src-ash:before { content: 'ash'; }
pre.src-dash:before { content: 'dash'; }
pre.src-ksh:before { content: 'ksh'; }
pre.src-mksh:before { content: 'mksh'; }
pre.src-posh:before { content: 'posh'; }
/* Additional Emacs modes also supported by the LaTeX listings package */
pre.src-ada:before { content: 'Ada'; }
pre.src-asm:before { content: 'Assembler'; }
pre.src-caml:before { content: 'Caml'; }
pre.src-delphi:before { content: 'Delphi'; }
pre.src-html:before { content: 'HTML'; }
pre.src-idl:before { content: 'IDL'; }
pre.src-mercury:before { content: 'Mercury'; }
pre.src-metapost:before { content: 'MetaPost'; }
pre.src-modula-2:before { content: 'Modula-2'; }
pre.src-pascal:before { content: 'Pascal'; }
pre.src-ps:before { content: 'PostScript'; }
pre.src-prolog:before { content: 'Prolog'; }
pre.src-simula:before { content: 'Simula'; }
pre.src-tcl:before { content: 'tcl'; }
pre.src-tex:before { content: 'TeX'; }
pre.src-plain-tex:before { content: 'Plain TeX'; }
pre.src-verilog:before { content: 'Verilog'; }
pre.src-vhdl:before { content: 'VHDL'; }
pre.src-xml:before { content: 'XML'; }
pre.src-nxml:before { content: 'XML'; }
/* add a generic configuration mode; LaTeX export needs an additional
(add-to-list 'org-latex-listings-langs '(conf " ")) in .emacs */
pre.src-conf:before { content: 'Configuration File'; }
table { border-collapse:collapse; }
caption.t-above { caption-side: top; }
caption.t-bottom { caption-side: bottom; }
td, th { vertical-align:top; }
th.org-right { text-align: center; }
th.org-left { text-align: center; }
th.org-center { text-align: center; }
td.org-right { text-align: right; }
td.org-left { text-align: left; }
td.org-center { text-align: center; }
dt { font-weight: bold; }
.footpara { display: inline; }
.footdef { margin-bottom: 1em; }
.figure { padding: 1em; }
.figure p { text-align: center; }
.equation-container {
display: table;
text-align: center;
width: 100%;
}
.equation {
vertical-align: middle;
}
.equation-label {
display: table-cell;
text-align: right;
vertical-align: middle;
}
.inlinetask {
padding: 10px;
border: 2px solid gray;
margin: 10px;
background: #ffffcc;
}
#org-div-home-and-up
{ text-align: right; font-size: 70%; white-space: nowrap; }
textarea { overflow-x: auto; }
.linenr { font-size: smaller }
.code-highlighted { background-color: #ffff00; }
.org-info-js_info-navigation { border-style: none; }
#org-info-js_console-label
{ font-size: 10px; font-weight: bold; white-space: nowrap; }
.org-info-js_search-highlight
{ background-color: #ffff00; color: #000000; font-weight: bold; }
.org-svg { width: 90%; }
/*]]>*/-->
</style>
<link rel="stylesheet" type="text/css" href="https://brettviren.github.io/moo/other/readtheorg/css/htmlize.css"/>
<link rel="stylesheet" type="text/css" href="https://brettviren.github.io/moo/other/readtheorg/css/readtheorg.css"/>
<script type="text/javascript" src="https://brettviren.github.io/moo/other/lib/js/jquery.min.js"></script>
<script type="text/javascript" src="https://brettviren.github.io/moo/other/lib/js/bootstrap.min.js"></script>
<script type="text/javascript" src="https://brettviren.github.io/moo/other/lib/js/jquery.stickytableheaders.min.js"></script>
<script type="text/javascript" src="https://brettviren.github.io/moo/other/readtheorg/js/readtheorg.js"></script>
<style> #content{max-width:1800px;}</style>
<style> p{max-width:800px;}</style>
<style> li{max-width:800px;}</style>
<style> pre.src{border-radius: 5px; background-color:#333; color:#0f0;}</style>
<style> pre.example{border-radius: 5px; background-color:#333; color:#0f0;}</style>
<style> code{border-radius: 5px; background-color:#333; color:#0f0;}</style>
<script type="text/javascript">
// @license magnet:?xt=urn:btih:e95b018ef3580986a04669f1b5879592219e2a7a&dn=public-domain.txt Public Domain
<!--/*--><![CDATA[/*><!--*/
function CodeHighlightOn(elem, id)
{
var target = document.getElementById(id);
if(null != target) {
elem.classList.add("code-highlighted");
target.classList.add("code-highlighted");
}
}
function CodeHighlightOff(elem, id)
{
var target = document.getElementById(id);
if(null != target) {
elem.classList.remove("code-highlighted");
target.classList.remove("code-highlighted");
}
}
/*]]>*///-->
// @license-end
</script>
</head>
<body>
<div id="content">
<h1 class="title"><code>moo</code> 無 <i>otypes</i>
<br />
<span class="subtitle">Defining objects with <code>moo</code> <i>oschema</i> types</span>
</h1>
<div id="table-of-contents">
<h2>Table of Contents</h2>
<div id="text-table-of-contents">
<ul>
<li><a href="#orgecd762d">Overview</a></li>
<li><a href="#org605354b">Usage</a>
<ul>
<li><a href="#orge03b3fe">Individual type construction</a></li>
<li><a href="#org069d001">Schema structure array</a></li>
<li><a href="#org8df1c30">Load types from file</a></li>
</ul>
</li>
<li><a href="#org9793c0c">Help</a></li>
</ul>
</div>
</div>
<div id="outline-container-orgecd762d" class="outline-2">
<h2 id="orgecd762d">Overview</h2>
<div class="outline-text-2" id="text-orgecd762d">
<p>
<b>moo</b> <i>otypes</i> is way to produce instances of <i>oschema</i> types that tries to
follow a <i>valid-by-construction</i> pattern. In general, <i>otypes</i> are native
language types (eg those of Python) which derive from <i>oschema</i> schema
data structures.
</p>
<p>
For example, in the <a href="oschema.html">oschema</a> document we saw some basic use of the
general <i>otypes</i> pattern applied as C++ codegen in the <code>structs.hpp.j2</code>
and <code>nljs.hpp.j2</code> templates. When instantiating a codegen'ed C++ <code>struct</code>
we have some immediate validity guarantees. They may then
automatically transfer to a JSON object that may be derived from the
C++ <code>struct</code>.
</p>
<p>
The rest of this document describes how <b>moo</b> applies the <i>otypes</i> pattern
in Python. With the use of the <code>moo.otypes</code> Python module, user code
may access Python classes corresponding to <i>oschema</i> types and in
instantiating them as Python objects gain some <i>valid-by-construction</i>
guarantees.
</p>
<div class="info" id="org606fe88">
<p>
See also <a href="https://brettviren.github.io/dune-daq-repl/ddcmd.html">DUNE DAQ Command Object Creation</a> which describes <code>moo.otypes</code>
in the context of one particular application.
</p>
</div>
</div>
</div>
<div id="outline-container-org605354b" class="outline-2">
<h2 id="org605354b">Usage</h2>
<div class="outline-text-2" id="text-org605354b">
<p>
The <code>moo.otypes</code> module provides high level functions to construct types
from <i>oschema</i>. They make use of lower-level Python metaprogramming for
the actual type construction which is also in this module.
</p>
</div>
<div id="outline-container-orge03b3fe" class="outline-3">
<h3 id="orge03b3fe">Individual type construction</h3>
<div class="outline-text-3" id="text-orge03b3fe">
<p>
We may make an individual type from <i>oschema</i> data structure which is
expressed as keyword arguments to the <code>moo.otypes.make_type()</code> function.
For example:
</p>
<div class="org-src-container">
<pre class="src src-python">import moo.otypes
Age = moo.otypes.make_type(
name="Age", doc="An age in years",
schema="number", dtype='i4', path='a.b')
myage = Age(42) # my forever age
print(f'{Age}, {myage}, {myage.pod()}')
import a.b
myage2 = Age(18)
print(f'{a.b.Age}, {myage2}, {myage2.pod()}')
</pre>
</div>
<pre class="example">
['name', 'doc', 'schema', 'dtype', 'path']
{'name': 'Age', 'doc': 'An age in years', 'schema': 'number', 'dtype': 'i4', 'path': 'a.b'}
<class 'a.b.Age'>, <number Age: 42>, 42
['name', 'doc', 'schema', 'dtype', 'path']
{'name': 'Age', 'doc': 'An age in years', 'schema': 'number', 'dtype': 'i4', 'path': 'a.b'}
<class 'a.b.Age'>, <number Age: 18>, 18
</pre>
<div class="note" id="orgb40fe10">
<p>
The <code>moo.otypes.make_type()</code> directly returns a Python type object (aka
Python class) and it "places" the type object into the module tree
given the schema structure's <code>.path</code> attribute.
</p>
</div>
<p>
We may try to use our otype with invalid data:
</p>
<pre class="example" id="org1006d9e">
myage = Age("older than the hills")
</pre>
<p>
Which will return an error like:
</p>
<pre class="example" id="orgda8e455">
Traceback (most recent call last):
File "<stdin>", line 8, in <module>
File "<number Age>", line 13, in __init__
File "/home/bv/dev/moo/moo/otypes.py", line 485, in update
self._value = numpy.array(val, dtype)
ValueError: invalid literal for int() with base 10: 'older than the hills'
</pre>
<p>
This error illustrates how the <i>valid-by-construction</i> pattern works.
It's not that magic is performed and the data is miraculously valid.
Rather, we the developer are immediately punished if we attempt to
violate the schema.
</p>
<div class="note" id="orgf59c589">
<p>
We may also produce an object from these (or more generic) types and
validate that object against schema. It is important to know that the
constraints asserted by these two validation procedures are somewhat
disjoint. As <code>moo.otypes</code> matures it may gain more rigor, but for now
the JSON Schema based validation on a final object will catch mistakes
that <code>moo.otypes</code> will miss during object construction.
</p>
</div>
</div>
</div>
<div id="outline-container-org069d001" class="outline-3">
<h3 id="org069d001">Schema structure array</h3>
<div class="outline-text-3" id="text-org069d001">
<p>
Creation of a <i>system of related types</i> is done with an array of data
structures describing its schema and the Python types are constructed
with the plural function <code>moo.otypes.make_types()</code>. For example:
</p>
<div class="org-src-container">
<pre class="src src-python">import moo.otypes
schema = [dict(name="Pet", schema="enum",
symbols=["cat", "dog", "early personal computer"],
default="cat",
path="my.home.office",
doc="A kind of pet"),
dict(name="Desk", schema="record",
fields=[
dict(name="ontop", item="my.home.office.Pet"),
],
path="my.home.office",
doc="Model my desk")]
moo.otypes.make_types(schema)
from my.home.office import Desk, Pet
desk = Desk(ontop="cat")
print(f'{Desk}, {desk}, {desk.pod()}, {desk.ontop}')
</pre>
</div>
<pre class="example">
<class 'my.home.office.Desk'>, <record Desk, fields: {ontop}>, {'ontop': 'cat'}, cat
</pre>
<div class="note" id="org38837ba">
<p>
The schema structure array is assumed to be sorted in topological
order of type dependencies. Here, this is implicitly assured by how
the <code>schema</code> array is formed. In more complex code one may rely on
<code>moo.oschema.toposort()</code> to produce a sorted schema array.
</p>
</div>
</div>
</div>
<div id="outline-container-org8df1c30" class="outline-3">
<h3 id="org8df1c30">Load types from file</h3>
<div class="outline-text-3" id="text-org8df1c30">
<p>
The highest layer function is <code>moo.otypes.load_types()</code>. It is a mere
convenience function that combines the <b>moo</b> method to load a schema
file and a call to <code>make_types()</code> on the result.
</p>
<div class="note" id="org2efe572">
<p>
Any file format that <b>moo</b> supports may be used to provide schema, while
Jsonnet is recommended. See the <a href="oschema.html">oschema</a> document for more details on
how to construct schema files.
</p>
</div>
<p>
We can see <code>load_types()</code> in action using a schema that is part of the
<b>moo</b> test suite:
</p>
<div class="org-src-container">
<pre class="src src-python">import os
import moo.otypes
# Directly make a type in Python to use for an "any" below
moo.otypes.make_type(schema="string", name="Uni", path="test.basetypes")
from test.basetypes import Uni
# We locate and load a test schema file
here = os.path.join(os.path.dirname(__file__), "test")
types = moo.otypes.load_types("test-ogen-oschema.jsonnet", [here])
from app import Person
per = Person(email="[email protected]", counts=[42],
affil=Uni("Snooty U"), mbti="judging")
print(f'{Person}, {per}, {per.affil}')
print(per.pod())
</pre>
</div>
<div class="note" id="org432ec87">
<p>
In the above we give <code>load_types()</code> a file system path (ie, <code>[here]</code>) so
that files in the <b>moo</b> test directory will be located. <b>moo</b> will search
this path when a file is given as a relative path.
</p>
<p>
When using the <code>moo</code> Python module the application may set a default
path instead of providing one to every <code>moo.io.load()</code> call (which
<code>load_types()</code> forwards to). An example of this usage is given below.
</p>
<p>
When using the <code>moo</code> CLI one may set the environment variable
<code>MOO_LOAD_PATH</code> to equivalently provide this default load path.
</p>
</div>
</div>
</div>
</div>
<div id="outline-container-org9793c0c" class="outline-2">
<h2 id="org9793c0c">Help</h2>
<div class="outline-text-2" id="text-org9793c0c">
<p>
Type information and any <code>doc</code> strings given in the schema are reflected
into the constructed Python types. This information can be displayed
using usual Python meta interrogation methods. For example:
</p>
<div class="org-src-container">
<pre class="src src-python">import os
import moo.otypes
import moo.io
here = os.path.join(os.path.dirname(__file__), "test")
moo.io.default_load_path = [here]
types = moo.otypes.load_types("test-ogen-oschema.jsonnet")
from app import Person
help(Person)
</pre>
</div>
<pre class="example" id="orgb5c7f41">
Help on class Person in module app:
class Person(moo.otypes._Record)
| Person(*args, email: app.Email = None, email2: app.Email = '[email protected]', counts: app.Counts = None, affil: app.Affiliation = None, mbti: app.MBTI = 'introversion')
|
| Record type Person with fields: "email", "email2", "counts", "affil", "mbti"
|
| Describe everything there is to know about an individual human
|
| Method resolution order:
| Person
| moo.otypes._Record
| moo.otypes.BaseType
| abc.ABC
| builtins.object
|
| Methods defined here:
|
| __init__(self, *args, email: app.Email = None, email2: app.Email = '[email protected]', counts: app.Counts = None, affil: app.Affiliation = None, mbti: app.MBTI = 'introversion')
| Create a record type of Person
|
| ----------------------------------------------------------------------
| Data descriptors defined here:
|
| affil
|
| counts
|
| email
|
| email2
|
| mbti
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
| __abstractmethods__ = frozenset()
|
| ----------------------------------------------------------------------
| Methods inherited from moo.otypes._Record:
|
| __repr__(self)
| Return repr(self).
|
| pod(self)
| Return record as plain old data.
|
| Will perform validation.
|
| update(self, *args, **kwds)
| Update a record.
|
| An arg in args may be one of:
| - a JSON string
| - a dictionary
| - an instance of a record of same type.
|
| kwds may be a dictionary.
|
| Dictionaries are taken to be field settings, values can be POD
| or a typed object consistent with the field type.
|
| ----------------------------------------------------------------------
| Readonly properties inherited from moo.otypes._Record:
|
| field_names
| Return list of field names
|
| fields
| Return mapping of field name to field dict
|
| ----------------------------------------------------------------------
| Readonly properties inherited from moo.otypes.BaseType:
|
| ost
| The object schema type
|
| ----------------------------------------------------------------------
| Data descriptors inherited from moo.otypes.BaseType:
|
| __dict__
| dictionary for instance variables (if defined)
|
| __weakref__
| list of weak references to the object (if defined)
</pre>
</div>
</div>
</div>
<div id="postamble" class="status">
<p class="author">Author: Brett Viren</p>
<p class="date">Created: 2021-06-16 Wed 16:52</p>
<p class="validation"><a href="https://validator.w3.org/check?uri=referer">Validate</a></p>
</div>
</body>
</html>