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curious behaviour - disappearing variable scope

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Ben Coman

curious behaviour - disappearing variable scope

I'm curious about the following behaviour...

"In Playground, first evaluate..."

s := Semaphore new.

[ [ s wait. Transcript crShow: 'x' ] whileTrue ] fork.

"then later..."

s signal.

==> 'x' is seen in Transcript

but then an error pops up "#wait was sent to nil"

So... 's' *was* valid and then its not?

cheers -ben

Ben Coman

Re: curious behaviour - disappearing variable scope

On 1 June 2018 at 14:59, Ben Coman <[hidden email]> wrote:

I'm curious about the following behaviour...

"In Playground, first evaluate..."
s := Semaphore new.
[ [ s wait. Transcript crShow: 'x' ] whileTrue ] fork.

"then later..."
s signal.

==> 'x' is seen in Transcript
but then an error pops up "#wait was sent to nil"

So... 's' *was* valid and then its not?

cheers -ben

Sorry I got distracted. I should have added version info...

Image

-----

C:\PharoLauncher\images\Pharo-7.0.0-alpha.build.994.sha.6b52ae6.arch.32bit\Pharo-7.0.0-alpha.build.994.sha.6b52ae6.arch.32bit.image

Pharo7.0alpha

Build information: Pharo-7.0+alpha.build.994.sha.6b52ae62b755d8778fa0b5a4ac53b39b6c107dc9 (32 Bit)

Unnamed

Virtual Machine

---------------

C:\Users\Ben\Documents\Pharo\vms\70-x86\Pharo.exe

CoInterpreter VMMaker.oscog-eem.2361 uuid: 7ca2f89a-de70-422f-b92b-54f91ac4e47b Apr 12 2018

StackToRegisterMappingCogit VMMaker.oscog-eem.2361 uuid: 7ca2f89a-de70-422f-b92b-54f91ac4e47b Apr 12 2018

VM: 201804122226 https://github.com/OpenSmalltalk/opensmalltalk-vm.git $ Date: Thu Apr 12 15:26:17 2018 -0700 $ CommitHash: 07c6dc3 $ Plugins: 201804122226 https://github.com/OpenSmalltalk/opensmalltalk-vm.git $

Win32 built on Apr 12 2018 22:41:03 GMT Compiler: 6.4.0

VMMaker versionString VM: 201804122226 https://github.com/OpenSmalltalk/opensmalltalk-vm.git $ Date: Thu Apr 12 15:26:17 2018 -0700 $ CommitHash: 07c6dc3 $ Plugins: 201804122226 https://github.com/OpenSmalltalk/opensmalltalk-vm.git $

CoInterpreter VMMaker.oscog-eem.2361 uuid: 7ca2f89a-de70-422f-b92b-54f91ac4e47b Apr 12 2018

StackToRegisterMappingCogit VMMaker.oscog-eem.2361 uuid: 7ca2f89a-de70-422f-b92b-54f91ac4e47b Apr 12 2018

VM as selected by PharoLauncher.

cheers -ben

Ben Coman

Re: curious behaviour - disappearing variable scope

On 1 June 2018 at 15:23, Ben Coman <[hidden email]> wrote:

On 1 June 2018 at 14:59, Ben Coman <[hidden email]> wrote:
I'm curious about the following behaviour...

"In Playground, first evaluate..."
s := Semaphore new.
[ [ s wait.

Transcript crShow: 'x'

] whileTrue

] forkAt: 41.

Apologies for my brain freeze. It should have been...

s := Semaphore new.

[ [ s wait.

Transcript crShow: 'x'.

true ] whileTrue

] forkAt: 41.

But an error around the end of the block rather than the start would have been useful.

cheers -ben

"then later..."
s signal.

==> 'x' is seen in Transcript
but then an error pops up "#wait was sent to nil"

So... 's' *was* valid and then its not?

cheers -ben

Sven Van Caekenberghe-2

Re: curious behaviour - disappearing variable scope

There is also #repeat for 'infinite' loops

> On 1 Jun 2018, at 10:18, Ben Coman <[hidden email]> wrote:
>
>
>
> On 1 June 2018 at 15:23, Ben Coman <[hidden email]> wrote:
>
>
> On 1 June 2018 at 14:59, Ben Coman <[hidden email]> wrote:
> I'm curious about the following behaviour...
>
> "In Playground, first evaluate..."
> s := Semaphore new.
> [ [ s wait.
> Transcript crShow: 'x'
> ] whileTrue
> ] forkAt: 41.
>
> Apologies for my brain freeze. It should have been...
> s := Semaphore new.
> [ [ s wait.
> Transcript crShow: 'x'.
> true ] whileTrue
> ] forkAt: 41.
>
>
> But an error around the end of the block rather than the start would have been useful.
> cheers -ben
>
>
> "then later..."
> s signal.
>
> ==> 'x' is seen in Transcript
> but then an error pops up "#wait was sent to nil"
>
> So... 's' *was* valid and then its not?
>
> cheers -ben
>
>