On Mon, 27 Oct 2014, Clément Bera wrote:

Hey guys,
I was discussing about methods like that with Marcus:

MyClass>>foo
#(false) first 
ifFalse: [ 
'first call since compilation' logCr. 
#(false) at: 1 put: true ]
ifTrue: [ 'other calls' logCr ]

DoIt:
4 timesRepeat: [MyClass new foo ]

Transcript:
'first call since compilation'
'other calls'
'other calls'
'other calls'

In the sista image/VM, we are most probably going with Eliot to implement a slow path when you edit the literal of a method (deoptimizing the method) so we can consider that the literals are immutable in the
generic case (and if it's not true, execution falls back to a slow path).

But I was thinking, does it worth it to implement the slow path ? 
Couldn't we just put literals as immutable all the time ? 
The methods as the one shown before would not work any more. But does someone use it ?

This method was used in Seaside (or some Seaside extension) to cache the contents of files in methods.

By the way, how would you ensure immutability?

I mean, how would you prevent something like this?

MyClass >> foo

        ^#('placeHolder')

And then

(((MyClass >> #foo) literalAt: 1) at: 1) becomeForward: Object new


Levente

P.S.: why isn't this on the vm-dev list?

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