1
Type-ZERO - All Systems Nominal (MechWarrior Online Tribute)
Type-ZERO - All Systems Nominal (MechWarrior Online Tribute)
DATE: 2013/01/02::
2
Systems Nominal - First Look
Systems Nominal - First Look
DATE: 2014/12/23::
3
Data Types C# - common language runtime types, nominal storage allocation, and value range
Data Types C# - common language runtime types, nominal storage allocation, and value range
DATE: 2014/09/26::
4
Super View...Systems Nominal
Super View...Systems Nominal
DATE: 2014/12/23::
5
Scala
Scala's Type System: a tutorial
DATE: 2012/04/01::
6
All Systems Nominal: Episode #5 - Confrontation
All Systems Nominal: Episode #5 - Confrontation
DATE: 2013/07/19::
7
[MWO] All Systems Nominal
[MWO] All Systems Nominal
DATE: 2012/11/09::
8
Systems Nominal (Anything But)
Systems Nominal (Anything But)
DATE: 2014/12/23::
9
All Systems Nominal: Episode #3 - Equilibrium
All Systems Nominal: Episode #3 - Equilibrium
DATE: 2013/03/31::
10
All systems nominal
All systems nominal
DATE: 2013/09/28::
11
Reactor Online. Sensors Online. Weapons Online. All Systems Nominal.
Reactor Online. Sensors Online. Weapons Online. All Systems Nominal.
DATE: 2011/03/09::
12
All Systems Nominal: Episode #2 - Fright Night
All Systems Nominal: Episode #2 - Fright Night
DATE: 2013/02/23::
13
Top 30 Richest Countries in Africa by GDP Nominal
Top 30 Richest Countries in Africa by GDP Nominal
DATE: 2014/05/16::
14
All Systems Nominal
All Systems Nominal
DATE: 2012/06/20::
15
All Systems Nominal
All Systems Nominal
DATE: 2013/03/31::
16
BJR RACING - PB-40A Hydraulic CNC Metalmaster Pressbrake (S970F)
BJR RACING - PB-40A Hydraulic CNC Metalmaster Pressbrake (S970F)
DATE: 2014/12/04::
17
How to include Nominal Codes and create Sub Accounts - QuickBooks Online
How to include Nominal Codes and create Sub Accounts - QuickBooks Online
DATE: 2014/02/27::
18
SPSS: nominal explanatory variable in the Cox proportional hazard model
SPSS: nominal explanatory variable in the Cox proportional hazard model
DATE: 2013/01/12::
19
Logitech X530 PC Multimedia Home Theatre Speaker System 70 Watt Total 5.1
Logitech X530 PC Multimedia Home Theatre Speaker System 70 Watt Total 5.1
DATE: 2012/02/23::
20
AMADA/WASINO G-05 2-AXIS CNC HIGH SPEED GANG TYPE CHUCKER WITH GANTRY LOADING SYSTEM
AMADA/WASINO G-05 2-AXIS CNC HIGH SPEED GANG TYPE CHUCKER WITH GANTRY LOADING SYSTEM
DATE: 2014/11/05::
21
Piping Fittings Take Off NPS - Nominal Pipe Size 4 inch
Piping Fittings Take Off NPS - Nominal Pipe Size 4 inch
DATE: 2015/02/10::
22
HI-TEX Active spekers, Hornsonic
HI-TEX Active spekers, Hornsonic
DATE: 2011/04/17::
23
A Video about Variable Levels: Nominal, Ordinal, Interval, & Ratio
A Video about Variable Levels: Nominal, Ordinal, Interval, & Ratio
DATE: 2013/03/29::
24
[DOWNLOAD] MW3 Reactor online, sensors online, weapons online, all systems nominal
[DOWNLOAD] MW3 Reactor online, sensors online, weapons online, all systems nominal
DATE: 2012/03/10::
25
systems nominal new hack 2015
systems nominal new hack 2015
DATE: 2014/12/23::
26
Logitech Z506 Speaker System
Logitech Z506 Speaker System
DATE: 2011/11/28::
27
Golden Rules of Accounting,how to understand the concepts of Real,Personal and Nominal account rules
Golden Rules of Accounting,how to understand the concepts of Real,Personal and Nominal account rules
DATE: 2013/09/05::
28
APC Smart-UPS SC620 4-Outlet 620VA 390W UPS System
APC Smart-UPS SC620 4-Outlet 620VA 390W UPS System
DATE: 2014/08/26::
29
InScooter Foldable wheelchair
InScooter Foldable wheelchair
DATE: 2015/05/07::
30
How to Select the Right FRAM (F-RAM) for your Applications
How to Select the Right FRAM (F-RAM) for your Applications
DATE: 2013/10/21::
31
How to tell if your Samsung Galaxy S3 CPU is fast, nominal or slow.
How to tell if your Samsung Galaxy S3 CPU is fast, nominal or slow.
DATE: 2013/02/22::
32
2kW solar system - Smartflower POP
2kW solar system - Smartflower POP
DATE: 2015/06/02::
33
Assembleon (Philips) Gem Series Topaz Placement System
Assembleon (Philips) Gem Series Topaz Placement System
DATE: 2011/07/18::
34
DIATONE DS-77Z
DIATONE DS-77Z
DATE: 2014/06/12::
35
Multi strand system.avi
Multi strand system.avi
DATE: 2012/03/30::
36
JBL EON 210P Portable PA System @ Namm 2012 with DJkit.tv
JBL EON 210P Portable PA System @ Namm 2012 with DJkit.tv
DATE: 2012/01/31::
37
Creative T6160 5.1 Unboxing
Creative T6160 5.1 Unboxing
DATE: 2011/01/14::
38
NEW Subaru WRX STI 2015 Impreza official video
NEW Subaru WRX STI 2015 Impreza official video
DATE: 2014/01/14::
39
Video review "MyTinySun" HEAD 1000 PRO Lighting System.
Video review "MyTinySun" HEAD 1000 PRO Lighting System.
DATE: 2013/11/19::
40
Enter data and define variables in SPSS
Enter data and define variables in SPSS
DATE: 2013/08/12::
41
Audio test - Dance Music on Creative p380 system
Audio test - Dance Music on Creative p380 system
DATE: 2015/01/06::
42
PROpak Portable Foam System
PROpak Portable Foam System
DATE: 2014/05/16::
43
My CRAIGSLIST FIND FOR TODAY
My CRAIGSLIST FIND FOR TODAY
DATE: 2014/06/01::
44
AEMC® - PEL App For Android™
AEMC® - PEL App For Android™
DATE: 2014/08/08::
45
SELF-EXPANDING NITINOL STENT "JAGUAR" with delivery system
SELF-EXPANDING NITINOL STENT "JAGUAR" with delivery system
DATE: 2014/02/28::
46
Changing Battery - Razor MX650 Dirt Rocket
Changing Battery - Razor MX650 Dirt Rocket
DATE: 2014/12/12::
47
Logitech X-140 Speakers Unboxing & Inside Look
Logitech X-140 Speakers Unboxing & Inside Look
DATE: 2009/09/25::
48
Vintage Kef speakers Carina ii sp3017 3 way loudspeaker system 1983 FWO 80 watts
Vintage Kef speakers Carina ii sp3017 3 way loudspeaker system 1983 FWO 80 watts
DATE: 2015/03/28::
49
Razor MX650 (+LiFePO4) First Winter Ride - way
Razor MX650 (+LiFePO4) First Winter Ride - way 'Hobby marketplace - Preobrazhenskaya Ploschad'
DATE: 2014/12/14::
50
KRK KNS 8400 Unboxing
KRK KNS 8400 Unboxing
DATE: 2012/05/18::
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From Wikipedia, the free encyclopedia
  (Redirected from Nominative type system)
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In computer science, a nominal or nominative type system (or name-based type system) is a major class of type system, in which compatibility and equivalence of data types is determined by explicit declarations and/or the name of the types. Nominal systems are used to determine if types are equivalent, as well as if a type is a subtype of another. It contrasts with structural systems, where comparisons are based on the structure of the types in question and do not require explicit declarations.

Nominal typing[edit]

Nominal typing means that two variables are type-compatible if and only if their declarations name the same type. For example, in C++, two struct types with different names are never considered compatible, even if they have identical field declarations.

However, C++ also allows a typedef declaration, which introduces an alias for an existing type. These are merely syntactical and do not differentiate the type from its alias for the purpose of type checking. This feature, present in many languages, can result in a loss of type safety when (for example) the same primitive integer type is used in two semantically distinct ways. Haskell provides the C-style syntactic alias in the form of the type declaration, as well as the newtype declaration that does introduce a new, distinct type, isomorphic to an existing type.[1]

Nominal subtyping[edit]

In a similar fashion, nominal subtyping means that one type is a subtype of another if and only if it is explicitly declared to be so in its definition. Nominally-typed languages typically enforce the requirement that declared subtypes be structurally compatible (though Eiffel allows non-compatible subtypes to be declared). However, subtypes which are structurally compatible "by accident", but not declared as subtypes, are not considered to be subtypes.

C++, C#, Java, Objective-C, Delphi and Swift all primarily use both nominal typing and nominal subtyping.

Some nominally-subtyped languages, such as Java and C#, allow classes to be declared final (or sealed in C# terminology), indicating that no further subtyping is permitted.

Comparison[edit]

Nominal typing is useful at preventing accidental type equivalence, and is considered[by whom?] to have better type-safety than structural typing. The cost is a reduced flexibility, as, for example, nominal typing does not allow new super-types to be created without modification of the existing subtypes.

See also[edit]

Notes[edit]

References[edit]

External links[edit]

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