On Wed, 7 Aug 2013, psea wrote:
Ok, i've got it. So in ST it's just not allowed assign to a block argument
for some reason. Let's consider it a language feature. And it's ok,
It's a compiler bug. The compiler doesn't handle this case.
- TempVariableNode >> #analyseClosure: returns if the receiver is a block
argument without checking the preference.
- BlockNode >> #postNumberingProcessTempsWithin:rootNode: only checks the
temporaries, but not the arguments of the receiver.
- Even if the above two are fixed, the temp index is still out of bounds,
because removing arguments is not supported (see
#removeTempNode:ifAbsent: and its sender), so the original temp for the
argument will be kept.
different language - different rules. Thanks for pointing me on that!
Now, I've turn off allowBlockArgumentAssignment property.
What's worried me is that in other languages I'm familiar with it's a normal
thing to assign to a function argument (Scheme, C, Python, JavaScript).
Storing into a block or method argument is considered bad practice.
Support for it is/was planned to be removed. Even though it can yield
somewhat better performance, it's something you'll rarely see in
Smalltalk code.
answer to your questions:
Smalltalk vmVersion 'Squeak3.10.2 of 11 February 2010 [latest update:
#9314]'
SmalltalkImage current systemInformationString "ditto" 'Squeak4.3
latest update: #11860
Current Change Set: Unnamed1'
Windows XP.
PS But you should agree with me that
makeAcc := [ :acc |
[:n | acc:=acc+n. acc]]
looks a little bit better and concise than
makeAcc := [ :acc |
| total |
total:=acc.
[:n | total:=total+n. total]]
There's no need to explicitly return 'total' from the inner block, because
the assignment yields the same value:
makeAcc := [ :acc |
| total |
total := acc.
[ :n | total := total + n ] ]
Levente
:-)
And thanks for the links.
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