Curious assignment behaviour

[Dale Strickland-Clark]

I observe that the folowing works as some might expect:

x = y = 5

Assigns 5 to both x and y.

However the expression:

y = 5

does not yeild 5

 >>> print y = 5
 Traceback (  File "<interactive input>", line 1
     print y = 5
            ^
 SyntaxError: invalid syntax
 >>> 

So this is obviously a gludge in assignment. 

I'd be much happier if assignment yeilds the value assigned, as it
does in C (I believe).  It could then be used universaly.

Also, where is this curious behaviour documented? 6.3 of the Language
Ref makes no reference to it. (Go on. Prove me wrong!)

Thanks.
--
Dale Strickland-Clark
Riverhall Systems Ltd