Non-evaluating and / or

Hello

I would like to ask how to do non-evaluating and.
As far as I know, & should be evaluating and and: should be non-evaluating. However, I need to find a way how to use it properly.

In "conventional" languages I would expect to work it like in following example...
  false and: Transcript open
Since false is... false... there is no reason to evaluate Transcript open. But when I run this one in playground, transcript opens.

Any help is appreciated.

Jan

Hello,

You should but a block after "and:".
If you don't, the instruction will be always executed...
The block represents a kind of conditional action.

So if you want to do it works :
false and: [ Transcript open ]

Hoping that it will help,

Best,
Vincent BLONDEAU

-----Message d'origine-----
De : Pharo-users [mailto:[hidden email]] De la part de Jan B.
Envoyé : vendredi 3 avril 2015 12:10
À : [hidden email]
Objet : [Pharo-users] Non-evaluating and / or

Hello

I would like to ask how to do non-evaluating and.
As far as I know, & should be evaluating and and: should be non-evaluating.
However, I need to find a way how to use it properly.

In "conventional" languages I would expect to work it like in following example...
  false and: Transcript open
Since false is... false... there is no reason to evaluate Transcript open.
But when I run this one in playground, transcript opens.

Any help is appreciated.

Jan



--
View this message in context: http://forum.world.st/Non-evaluating-and-or-tp4817211.html
Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.



Ce message et les pièces jointes sont confidentiels et réservés à l'usage exclusif de ses destinataires. Il peut également être protégé par le secret professionnel. Si vous recevez ce message par erreur, merci d'en avertir immédiatement l'expéditeur et de le détruire. L'intégrité du message ne pouvant être assurée sur Internet, la responsabilité de Worldline ne pourra être recherchée quant au contenu de ce message. Bien que les meilleurs efforts soient faits pour maintenir cette transmission exempte de tout virus, l'expéditeur ne donne aucune garantie à cet égard et sa responsabilité ne saurait être recherchée pour tout dommage résultant d'un virus transmis.

This e-mail and the documents attached are confidential and intended solely for the addressee; it may also be privileged. If you receive this e-mail in error, please notify the sender immediately and destroy it. As its integrity cannot be secured on the Internet, the Worldline liability cannot be triggered for the message content. Although the sender endeavours to maintain a computer virus-free network, the sender does not warrant that this transmission is virus-free and will not be liable for any damages resulting from any virus transmitted.

Of course, how could I have missed it before, thank you both :)

Jan

Blondeau Vincent wrote

Hello,

You should but a block after "and:".
If you don't, the instruction will be always executed...
The block represents a kind of conditional action.

So if you want to do it works :
false and: [ Transcript open ]

Hoping that it will help,

Best,
Vincent BLONDEAU

Peter Uhnák wrote

Hi,

that's because you need to pass a block, since you want to postpone to
execution.
i.e. false and: [Transcript open]. (otherwise the binary operation
Transcript open will take precedence over keyword false and:)
You can always look at the implementation of those things — I always learn
something from it. :)

»and: alternativeBlock«

Peter