Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Yes, the compiler is enforcing scope. Note that the scope of a variable is the lexical block it's part of - not just from the point of declaration onwards, but the whole scope. </p> <p>The compiler is complaining because the assignment to <code>postParent</code> is outside its scope (which is only the nested braces). If you tried to declare a new variable at the point where you're currently assigning to <code>postParent</code> the problem would be with the nested block, because the scope of <code>postParent</code> would include that nested block, even though it was before the declaration.</p> <p>Scopes are described in section 3.7 of the C# 3.0 specification.</p> <p>EDIT: To respond to your question edit.</p> <p>It's just two simple rules:</p> <ul> <li>you can't declare a local variable when another local variable with the same name is in scope</li> <li>the scope of a local variable is the block in which the declaration occurs</li> </ul> <p>I'm sure the language could have been designed such that the scope only began at the point of declaration, but I think it's simpler (in terms of language complexity) to consider scopes as just blocks - so all local variables declared in the same block have the same scope, for example. That makes life a lot simpler when considering captured variables, too - as what gets captured depends on the scope, and nested scopes make life interesting...</p> <p>EDIT: The language spec has this to say about the original lambda expression example - it's section 7.14.1:</p> <blockquote> <p>The optional anonymous-function-signature of an anonymous function defines the names and optionally the types of the formal parameters for the anonymous function. The scope of the parameters of the anonymous function is the anonymous-function-body. Together with the parameter list (if given), the anonymous-method-body constitutes a declaration space. For this reason, it is a compile-time error for the name of a parameter of the anonymous function to match the name of a local variable, local constant, or parameter whose scope includes the anonymous-method-expression or lambda-expression.</p> </blockquote> <p>Does that help?</p>
    singulars
    1. This table or related slice is empty.
    1. POChild Scope & CS0136
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USJon Skeet
    1. USJon Skeet
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POChild Scope & CS0136
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTDownMod
    1. CORegardless if that is why it enforces that rule, I still believe this is a defect in the CLR. Anonymous methods should definitely descope any variables created inside them from any other function, even it's as simple as the CLR adding a prefix to each variable in the delegate method.
      singulars
      1. PO
      1. USChris Marisic
    2. COThe CLR isn't involved at all here. It's a language decision. And I disagree entirely. The point is that the outer variables are available to the anonymous function, so the anonymous function can't redefine them, in exactly the same way as if the variable were redeclared in a "normal" block.
      singulars
      1. PO
      1. USJon Skeet
    3. COMakes sense since assuming the declaration is part of the whole scope block you'd have no way to know if the outer variable should be rolled into the anonymous function or not. If it was based on where the variable was scoped from you could allow this.
      singulars
      1. PO
      1. USJoshBerke
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload