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January 2017

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Re: [Pharo-dev] Looking for Pharo devs

by Santiago Bragagnolo

Hi there :). I'm curious, What's this about? On Wed, 11 Jan 2017 at 12:02 <miron(a)tutanota.de> wrote: > Hello, > > Looking for someone with thorough Pharo experience for some experimental > changes to the Pharo environment and language. Some areas you will > expertise in: > > 1. Syntax parser. > 2. AST. > 3. Thorough overall environment knowledge. > > For more details send an e-mail to miron(a)tutanota.de. >

Jan. 12, 2017

collection flatCollect: #something VS (collection collect: #something) flattened

by Julien Delplanque

Hello everyone, While using #flatCollect: on a collection, I realized that, for example, these two code snippets do not behave the same way: #(1 (1)) flatCollect: #yourself. "Raise an error because the array does not contain only collections" (#(1 (1)) collect: #yourself) flattened "Returns #(1 1) Shouldn't these two code snippets behave the same way? Thanks in advance for your answers. Regards, Julien

Jan. 12, 2017

Re: [Pharo-dev] subexpression precedence

by Jan Vrany

On Wed, 2017-01-11 at 21:38 -0800, Martin McClure wrote: > On 01/11/2017 04:54 PM, Jan Vrany wrote: > > Hi, I'm afraid this is not specified. There's no > > language specification (*) as such of Pharo or any > > other available smalltalk - at least not that I know > > (prove me if I'm wrong). > > The ANSI Smalltalk spec says > > "The individual statements are executed in left to right sequence," > butÂ > in context I believe that this just means that you execute the firstÂ > statement in the method, then the next, and so on. > > Ah, here it is. Section 3.4.5.3 says > > "The receiver and the arguments are evaluated before the message isÂ > sent. They are evaluated in a left-to-right order." > So that's pretty clear. Oops, I overlooked this. Thanks! Jan > > Regards, > > -Martin > >

Jan. 12, 2017

Re: [Pharo-dev] subexpression precedence

by Eliot Miranda

> On Jan 11, 2017, at 9:38 PM, Martin McClure <martin(a)hand2mouse.com> wrote: > >> On 01/11/2017 04:54 PM, Jan Vrany wrote: >> Hi, I'm afraid this is not specified. There's no >> language specification (*) as such of Pharo or any >> other available smalltalk - at least not that I know >> (prove me if I'm wrong). > > The ANSI Smalltalk spec says > > "The individual statements are executed in left to right sequence," but in context I believe that this just means that you execute the first statement in the method, then the next, and so on. > > Ah, here it is. Section 3.4.5.3 says > > "The receiver and the arguments are evaluated before the message is sent. They are evaluated in a left-to-right order." > So that's pretty clear. Thanks, Martin. I'm relieved :-). "a" seems superfluous. Hopefully there is only one left-to-right order ;-) > > Regards, > > -Martin > >

Jan. 12, 2017

Re: [Pharo-dev] subexpression precedence

by Martin McClure

On 01/11/2017 04:54 PM, Jan Vrany wrote: > Hi, I'm afraid this is not specified. There's no > language specification (*) as such of Pharo or any > other available smalltalk - at least not that I know > (prove me if I'm wrong). The ANSI Smalltalk spec says "The individual statements are executed in left to right sequence," but in context I believe that this just means that you execute the first statement in the method, then the next, and so on. Ah, here it is. Section 3.4.5.3 says "The receiver and the arguments are evaluated before the message is sent. They are evaluated in a left-to-right order." So that's pretty clear. Regards, -Martin

Jan. 12, 2017

Re: [Pharo-dev] subexpression precedence

by James Ladd

I think for Redline Smalltalk which is why I'm asking I'll make sure my test subexpressions yield the same result as the same subexpressions on Pharo :) On Thu, Jan 12, 2017 at 2:58 PM, Chris Muller <asqueaker(a)gmail.com> wrote: > > Other than humans generally read from > > (pardon me) > > Other than that the code is read from left to right... > >

Jan. 12, 2017

Re: [Pharo-dev] subexpression precedence

by James Ladd

>> a := b := c := d := 4 This one is straight forward but subexpressions, those with () around them are the topic. On Thu, Jan 12, 2017 at 2:54 PM, Chris Muller <asqueaker(a)gmail.com> wrote: > > Wow, I just skimmed the messages section in the blue book and you're > right. I think this is an omission and that it should be specified that > keyword message receiver and arguments are evaluated strictly > left-to-right. I don't know of a Smalltalk implementation that doesn't > evaluate in this order. > > This doesn't sound right. I don't know whether I can dig out a > reference quickly or not, but I learned that precedence *within* the [ > unary -> binary -> keyword ] is actually right to left, not left to > right. > > a := b := c := d := 4 > > executes right-to-left. Other than humans generally read from > left-to-right, are there other reasons it should run left-to-right in > other contexts? > >

Jan. 12, 2017

Re: [Pharo-dev] subexpression precedence

by Chris Muller

> Other than humans generally read from (pardon me) Other than that the code is read from left to right...

Jan. 12, 2017

Re: [Pharo-dev] subexpression precedence

by Chris Muller

> Wow, I just skimmed the messages section in the blue book and you're right. I think this is an omission and that it should be specified that keyword message receiver and arguments are evaluated strictly left-to-right. I don't know of a Smalltalk implementation that doesn't evaluate in this order. This doesn't sound right. I don't know whether I can dig out a reference quickly or not, but I learned that precedence *within* the [ unary -> binary -> keyword ] is actually right to left, not left to right. a := b := c := d := 4 executes right-to-left. Other than humans generally read from left-to-right, are there other reasons it should run left-to-right in other contexts?

Jan. 12, 2017

Re: [Pharo-dev] subexpression precedence

by Eliot Miranda

Hi Jan, > On Jan 11, 2017, at 4:54 PM, Jan Vrany <jan.vrany(a)fit.cvut.cz> wrote: > > Hi, I'm afraid this is not specified. There's no > language specification (*) as such of Pharo or any > other available smalltalk - at least not that I know > (prove me if I'm wrong). Wow, I just skimmed the messages section in the blue book and you're right. I think this is an omission and that it should be specified that keyword message receiver and arguments are evaluated strictly left-to-right. I don't know of a Smalltalk implementation that doesn't evaluate in this order. But thanks for the OP's question and for your response. I am surprised. > > Order in which subexpressions are evaluated is rarely specified. > IIRC, JVM Spec doesn't specify it either. > > If the question was rather "How does it work in current Pharo > implementation?", then it's easy to check, just add some sideffects > to subexpressions (like Transcript show) and see in what order > they're executed :-) > > (*) Specification in a sense of Java Language Spec, > C# Language Specification, C99 Spec and so on. > > Jan > >> On Wed, 2017-01-11 at 16:16 -0800, James Ladd wrote: >> Hi Pharo People, >> >> I know Smalltalk has precedence rules when subexpressions () are >> involved. >> >> 2 + ( (3 * 4) - 1 ) >> evaluated last ( (evaluated first) evaluated second ) >> >> That is the inner most subexpression is evaluated first. >> >> Given the following made up expression for the purposes of my >> question: >> >> self at: (self offset) - 1 put: (2 * (12 / 4)). >> >> Are there precedence rules for the subexpressions that are part of >> the >> keyword expression? >> ie: Should (self offset) - 1 be evaluated before (2 * (12 / 4)). >> >> My thinking is that with keywords the arguments are evaluated left to >> right >> - that is >> at: before put: but within each the regular subexpression precedence >> applies? >> >> - James. >> >> >> >> >> >> >> -- >> View this message in context: http://forum.world.st/subexpression-pre >> cedence-tp4929398.html >> Sent from the Pharo Smalltalk Developers mailing list archive at >> Nabble.com. _,,,^..^,,,_ (phone)

Jan. 12, 2017

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