Javascript Ternary Operator lvalue

Question

I was reading about the ternary operator in different languages, and noticed something interesting in the Javascript section. http://en.wikipedia.org/wiki/%3F:#JavaScript

The conditional operator in JavaScript has the same syntax and precedence structure as in the other BCPL-derived variants, but a significant difference exists in the semantics: it returns an l-value.

The first sentence states that the return of the ternary in javascript is an lvalue, so I tried some examples, with odd results (in the chrome console).

Given:

var a = { 'yo' : 'momma' }
var b = { 'yo' : 'cool' }
var bool = true


(bool? a : b).yo = 'LLJ'
//a is now { 'yo' : 'LLJ' }

(bool? a.yo : b.yo) = 'LLJ' //throws a reference error

Why does the first work and the second fail? (Logically they're the same statements, no?)

Answer 1

Wikipedia was wrong. The conditional operator returns an r-value, not an l-value.

The history of the article is quite interesting, so I've summarised it here:

• 30 August 2010: The Beginning
  JavaScript section created. Correctly says that in JavaScript the ternary operator returns an r-value, but incorrectly says that in C/C++/Java it returns an l-value. Only in C++ the ternary operator returns an l-value.

• 31 January 2011: Cannot yield an l-value in C
  C correctly removed from the JavaScript section because it doesn't return an l-value. Java remains.

• 15 February 2011: "Corrected"
  The comparison to Java and C++ is removed (the comment correctly says that Java never yielded an l-value), but oh no! JavaScript suddenly returns an l-value!

• 7 March 2011: Hope is restored...
  The incorrect "l-value" is changed to "value", linking to the Value article (which describes both l-values and r-values).

• 7 March 2011: ...but not for long
  The link text is changed to say "l-value".

• 7 September 2013: Three cheers for Qantas 94 Heavy!
  Thanks to this question, Wikipedia has been corrected.