Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p><strong>EDIT: THERE IS AN "OFFICIAL" ANSWER IN THIS LINK: <a href="http://code.google.com/p/closure-compiler/issues/detail?id=410#makechanges" rel="nofollow">http://code.google.com/p/closure-compiler/issues/detail?id=410#makechanges</a></strong></p> <p>I think an assignment to a variable, followed immediately by usage of that variable, can be inlined. However, if there is any statement in between that cannot be proven to be free of side-effects, then the compiler won't inline it.</p> <p>In your case, assignment to variable "start" is separated from the usage of "start" only by the assignment statement to "end". However, this statement is free of side-effects since Math.max is an internal function and the compiler knows that it is side-effect-free.</p> <p>However, in your case, assignment to variable "end" is separated from the usage of that variable by a statement, which is an assignment of "start" to a property. Now, I believe that the compiler does not assume that merely assigning to a property is always side-effect-free; that is because some properties, when assigned, actually cause different behavior, or change global state (such as RegExp). In some systems, property assignments actually trigger certain system-specific features (e.g. hardware interface) that may in-turn contain side-effects.</p> <p>That is why, sometimes, when you have code like this:</p> <pre><code>foo.bar = 1; foo.bar = 2; foo.bar = 3; </code></pre> <p>The compiler won't eliminate the first two statements since assignment to "bar" may have side effects.</p> <p>So, in your question, the variable "end" cannot be inlined because the statement <code>tb.selectionStart = start;</code> may have side effects (perhaps only in wierd cases).</p> <p><strong>If you make "tb" a local variable, or something that the compiler has complete control of (e.g. a simple object: <code>var tb = {};</code>), then you'll find that the compiler inlines all of the assignments just fine.</strong></p>
    singulars
    1. This table or related slice is empty.
    1. POWhy does Closure Compiler not shorten this?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USStephen Chung
    1. USStephen Chung
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POWhy does Closure Compiler not shorten this?
      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. VTUpMod
    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. VTAcceptedByOriginator
    1. COI see, but couldn't the compiler possibly be optimized in such a way that `Math.max` is seen as creating no side effects?
      singulars
      1. PO
      1. USpimvdb
    2. COMath.max is a JS internal function and has no side effects. This is in the compiler's externs file. However, your assignment to tb.selectionStart is not guaranteed to have no side-effects. An assignment to a var can only be inlined if there is no statement between the assignment and the usage that may potentially contain side-effects.
      singulars
      1. PO
      1. USStephen Chung
    3. COOh, I understand now. Wasn't aware of getters/setters that can do things when used too.
      singulars
      1. PO
      1. USpimvdb
 

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