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ReadingOnlyVariableBindings

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Colin Putney-3

ReadingOnlyVariableBindings

Hi everyone,

One oddity I discovered while working on Environments is that, when a binding is converted to read-only or read-write, all the methods that refer to that binding are recompiled.

Does anybody know why this is done?

Colin

Nicolas Cellier

Re: ReadingOnlyVariableBindings

See the method

isSpecialWriteBinding
"Return true if this variable binding is write protected, e.g.,
should not be accessed primitively but rather by sending #value:
messages"
^true

And its senders.
That means that a different byte code must be generated in order to
send #value rather than accessing the 2nd inst. var. directly.

Nicolas

2013/3/8 Colin Putney <[hidden email]>:

> Hi everyone,
>
> One oddity I discovered while working on Environments is that, when a
> binding is converted to read-only or read-write, all the methods that refer
> to that binding are recompiled.
>
> Does anybody know why this is done?
>
> Colin
>
>
>

Colin Putney-3

Re: ReadingOnlyVariableBindings

On Fri, Mar 8, 2013 at 12:42 PM, Nicolas Cellier <[hidden email]> wrote:

See the method

isSpecialWriteBinding
"Return true if this variable binding is write protected, e.g.,
should not be accessed primitively but rather by sending #value:
messages"
^true

And its senders.
That means that a different byte code must be generated in order to
send #value rather than accessing the 2nd inst. var. directly.

Nicolas

Aahh, that makes sense. Thanks.

Colin

Nicolas Cellier

Re: ReadingOnlyVariableBindings

2013/3/8 Colin Putney <[hidden email]>:

>
>
>
> On Fri, Mar 8, 2013 at 12:42 PM, Nicolas Cellier
> <[hidden email]> wrote:
>>
>> See the method
>>
>> isSpecialWriteBinding
>> "Return true if this variable binding is write protected, e.g.,
>> should not be accessed primitively but rather by sending #value:
>> messages"
>> ^true
>>
>> And its senders.
>> That means that a different byte code must be generated in order to
>> send #value rather than accessing the 2nd inst. var. directly.
>>
>> Nicolas
>
>
> Aahh, that makes sense. Thanks.
>
> Colin
>

More precisely
isSpecialReadBinding triggers read access thru #value
isSpecialWriteBinding triggers write access thru #value:
But I think you understood me :)

Nicolas

>
>

Colin Putney-3

Re: ReadingOnlyVariableBindings

On Fri, Mar 8, 2013 at 12:49 PM, Nicolas Cellier <[hidden email]> wrote:

More precisely

isSpecialReadBinding triggers read access thru #value
isSpecialWriteBinding triggers write access thru #value:
But I think you understood me :)

Yup, this is just what I was looking for.

Colin