StackOverflow2013

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plurals

PO
primarykey
Id
2583303
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
2
CommunityOwnedDate
CreationDate
2010-04-06T07:31:53.383
FavoriteCount
0
LastActivityDate
2010-04-06T07:31:53.383
LastEditDate
LastEditorUserId
0
OwnerUserId
217862
ParentId
2578872
PostTypeId
2
Score
4
ViewCount
0
LastEditorDisplayName
text
Body
Something is first-class if it is explicitly manipulable in the code. In other words, something is first-class if it can be programmatically manipulated at run-time. This closely relates to meta-programming in the sense that what you describe in the code (at development time) is one meta-level, and what exists at run-time is another meta-level. But the barrier between these two meta-levels can be blurred, for instance with reflection. When something is reified at run-time, it becomes explicitly manipulable. <ul> <li>We speak of first-class object, because objects can be manipulated programmatically at run-time (that's the very purpose).</li> <li>In java, you have classes, but they are not first-class, because the code can normally not manipulate a class unless you use reflection. But in Smalltalk, classes are first-class: the code can manipulate a class like an regular object.</li> <li>In java, you have packages (modules), but they are not first-class, because the code does not manipulate package at run-time. But in NewSpeak, packages (modules) are first-class, you can instantiate a module and pass it to another module to specify the modularity at run-time.</li> <li>In C#, you have closures which are first-class functions. They exist and can be manipulated at run-time programmatically. Such things does not exists (yet) in java.</li> </ul> To me, the boundary first-class/not first-class is not exactly strict. It is sometimes hard to pronounce for some language constructs, e.g. java primitive types. We could say it's not first-class because it's not an object and is not manipulable through a reference that can be passed along, but the primitive value does still exists and can be manipulated at run-time. PS: I agree with Norman Ramsey and 2nd-class and 3rd-class value make no sense to me.
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Title
singulars
PostAcceptedAnswerId
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PostParentId
1. POAbout first-,second- and third-class value
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 PostTypePostTypeId
 PTQuestion
PostTypePostTypeId
1. PTAnswer
UserLastEditorUserId
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UserOwnerUserId
1. USewernli
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PostLinksPostIdRelatedPostId
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PostLinksRelatedPostIdPostId
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PostsAcceptedAnswerId
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PostsParentIdCreationDate
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VotesPostIdCreationDate
1. VO
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 UserUserId
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 VTUpMod
2. VO
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3. VO
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CommentsPostId
1. This table or related slice is empty.

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