- Pharo-users - lists.pharo.org

Re: Too many parenthesis - a matter of syntax

by Russ Whaley

What I like about parentheses (and I hate parentheses) is that it allows me to view/describe the intent of the code. When parens are not used, it is up to me (perhaps years later) to determine whether the original developer (sometimes me) understood (or not) the actual 'order of processing'. Parens - or another vehicle - should help me understand the intent (as would detailed comments) - so I can devise tests (oh yeah, are those available, too?) for the intent - even if it is just me in the debugger. So, I'm for whatever helps me understand the intent of the code - even if there is some slick way to nest everything. I generally prefer breaking nested processes down into multiple steps. Benchmarking rarely shows significant performance differences, for me. (and I've used parentheses 7 times in this one email!) :-) Russ On Wed, Jan 26, 2022 at 4:20 AM Kasper Osterbye <kasper.osterbye(a)gmail.com> wrote: > Cheers all > > I have noticed that I often ends up with quite a number of nested > expressions, for example: > > (((json at: 'tree') > select: [ :e | (e at: 'type') = âblob' ]) > collect: [:e | Path from: (e at: 'path')]) > select: [ :p | p segments last > in: [ :name | (name endsWith: '.md') | > (name endsWith: '.mic') ] ] > > What kind of proposals (if any) have been for a different syntax which > could give a more streamlined syntax? > > My own thinking has been around an alternative to the cascade semicolon. > What symbol to use does not matter for me, but something like > json at: âtree' Âº > select: [ :e | ((e at: 'type') = 'blobâ)]Âº > collect: [:e | Path from: (e at: 'pathâ)]Âº > select: [ :p | p segments last > in: [ :name | (name endsWith: '.md') | (name endsWith: > '.mic') ] ] > > Basically, a send the right hand expression to the result of the left hand > expression. > > Has anyone ever tried this, or is it just one of the many small annoyances > best left alone? > > Best, > > Kasper -- Russ Whaley whaley.russ(a)gmail.com

Jan. 27, 2022

Re: Too many parenthesis - a matter of syntax

by Vitor Medina Cruz

I understand the point of not adding more syntax and I agree with it, but I think this is such big missing feature in Pharo and that it could be provided by default in the image as an API instead of a syntax sugar. https://github.com/dvmason/Pharo-Functional has both approaches â syntax and API â and I really like the `chain` strategy â I had implemented one of my own some years ago based on a suggestion made here on this list. So the original example code would be like this: json *chain* at: âtree'; select: [ :e | ((e at: 'type') = 'blobâ)]; collect: [:e | Path from: (e at: 'pathâ)]; select: [ :p | p segments last in: [ :name | (name endsWith: '.md') | (name endsWith: '.mic') ] ] The chain stores the last returned object to be used as the receiver of the next message send. You can do it using a DNU, but maybe there is a more optimized way of doing it, and also using DNU do not work with messages present on the chain base class (Object), maybe tehre is a way to circumvent that also. Regards, Vitor On Wed, Jan 26, 2022 at 11:33 AM Richard Sargent < richard.sargent(a)gemtalksystems.com> wrote: > On Wed, Jan 26, 2022 at 4:40 AM Sven Van Caekenberghe <sven(a)stfx.eu> > wrote: > >> Hi Kaspar, >> >> I found the initial example actually reasonable readable. >> >> However, I would simplify it as follows: >> >> (json at: #tree) >> select: [ :each | >> ((each at: #type) = #blob) >> and: [ #(md mic) includes: (Path from: (each at: #path)) extension >> ] ]. >> >> I would personally not try to extend the Smalltalk syntax. The cost is >> not worth the gain. >> >> Tools could be written to help in dealing with deeply nested structures >> (JSON/XML), they could form their own DSL at a higher level. >> >> For a limited example, NeoJSONObject uses the DNU trick to support unary >> accessors: >> >> json at: #tree >> >> can be written as >> >> json tree >> >> and has a path accessor: >> >> json atPath: #(tree field name) >> >> it also behaves like JavaScript objects in that missing keys are nil. It >> is not that all this is good or better, it is just handy in some cases. >> Your code would then be even simpler (less parenthesis): >> >> json tree select: [ :each | >> (each type = #blob) >> and: [ #(md mic) includes: (Path from: each path) extension ] ]. >> > > That is the kind of expressiveness I was looking for! > > > >> Sven >> >> > On 26 Jan 2022, at 10:19, Kasper Osterbye <kasper.osterbye(a)gmail.com> >> wrote: >> > >> > Cheers all >> > >> > I have noticed that I often ends up with quite a number of nested >> expressions, for example: >> > >> > (((json at: 'tree') >> > select: [ :e | (e at: 'type') = âblob' ]) >> > collect: [:e | Path from: (e at: 'path')]) >> > select: [ :p | p segments last >> > in: [ :name | (name endsWith: '.md') | >> (name endsWith: '.mic') ] ] >> > >> > What kind of proposals (if any) have been for a different syntax which >> could give a more streamlined syntax? >> > >> > My own thinking has been around an alternative to the cascade >> semicolon. What symbol to use does not matter for me, but something like >> > json at: âtree' Âº >> > select: [ :e | ((e at: 'type') = 'blobâ)]Âº >> > collect: [:e | Path from: (e at: 'pathâ)]Âº >> > select: [ :p | p segments last >> > in: [ :name | (name endsWith: '.md') | (name endsWith: >> '.mic') ] ] >> > >> > Basically, a send the right hand expression to the result of the left >> hand expression. >> > >> > Has anyone ever tried this, or is it just one of the many small >> annoyances best left alone? >> > >> > Best, >> > >> > Kasper >> >

Jan. 26, 2022

Re: isAbstract in WAIPSessionTrackingStrategy meet my new hobby horse

by Marcus Denker

Y > On 26 Jan 2022, at 15:55, gettimothy via Pharo-users <pharo-users(a)lists.pharo.org> wrote: > > WAIPSessionTrackingStrategy > isAbstract > ^true > has just ran into my new hobby horse. > > I am reading through every class in Seaside to document it and I had an 'aha!' moment > > on the design of Abstract super classes like WABrush: > > WABrush > isAbstract > > ^ self == WABrush > > > The simplicity is genius because no subclass of WABrush has to implement isAbstract, whereas in WAIPSessionTrackingStrategy, concrete subclasses (of which there currently are none) will have to. > Exactly, that is the idea of the pattern. On the downside it is not easy to understand (you have to think about it the first time you see it) and it feels (to me) âuglyâ. Maybe because it encodes meta-data of the class, which should be declarative, as a method? Instead of improving the meta-model (and thus our understanding) of what a class is? But it is the best we have now. There is even a âmake class abstractâ refactoring method in Pharo10, and we adapted the Code Critique to not complain about the direct class reference for these methods. > In defense of the WAIPSessionTrackingStrategy implementation, the comment reads: > I track sessions using the remote address of a client. > Usually you don't want to use this because it causes troubles when multiple users share the same IP (eg. several users from the same company). > > That's why I'm marked as abstract. > > There are some special cases like crawlers where it can work though. > > So, apparently, the author is anticipating somebody someday using it. > Maybe you can add an issue to the seaside issue tracker? Marcus

Jan. 26, 2022

isAbstract in WAIPSessionTrackingStrategy meet my new hobby horse

by gettimothy

WAIPSessionTrackingStrategyÂ > isAbstract Â Â ^true has just ran into my new hobby horse. I am reading through every class in Seaside to document it and I had an 'aha!' moment on the design of Abstract super classes like WABrush: WABrush > isAbstract Â Â Â Â Â Â ^ self == WABrush The simplicity is genius because no subclass of WABrush has to implement isAbstract, whereas in WAIPSessionTrackingStrategy, concrete subclasses (of which there currently are none) will have to. In defense of the WAIPSessionTrackingStrategy implementation, the comment reads: I track sessions using the remote address of a client. Usually you don't want to use this because it causes troubles when multiple users share the same IP (eg. several users from the same company). That's why I'm marked as abstract. There are some special cases like crawlers where it can work though. Â So, apparently, the author is anticipating somebody someday using it.

Jan. 26, 2022

Re: Too many parenthesis - a matter of syntax

by Richard Sargent

On Wed, Jan 26, 2022 at 4:40 AM Sven Van Caekenberghe <sven(a)stfx.eu> wrote: > Hi Kaspar, > > I found the initial example actually reasonable readable. > > However, I would simplify it as follows: > > (json at: #tree) > select: [ :each | > ((each at: #type) = #blob) > and: [ #(md mic) includes: (Path from: (each at: #path)) extension ] > ]. > > I would personally not try to extend the Smalltalk syntax. The cost is not > worth the gain. > > Tools could be written to help in dealing with deeply nested structures > (JSON/XML), they could form their own DSL at a higher level. > > For a limited example, NeoJSONObject uses the DNU trick to support unary > accessors: > > json at: #tree > > can be written as > > json tree > > and has a path accessor: > > json atPath: #(tree field name) > > it also behaves like JavaScript objects in that missing keys are nil. It > is not that all this is good or better, it is just handy in some cases. > Your code would then be even simpler (less parenthesis): > > json tree select: [ :each | > (each type = #blob) > and: [ #(md mic) includes: (Path from: each path) extension ] ]. > That is the kind of expressiveness I was looking for! > Sven > > > On 26 Jan 2022, at 10:19, Kasper Osterbye <kasper.osterbye(a)gmail.com> > wrote: > > > > Cheers all > > > > I have noticed that I often ends up with quite a number of nested > expressions, for example: > > > > (((json at: 'tree') > > select: [ :e | (e at: 'type') = âblob' ]) > > collect: [:e | Path from: (e at: 'path')]) > > select: [ :p | p segments last > > in: [ :name | (name endsWith: '.md') | > (name endsWith: '.mic') ] ] > > > > What kind of proposals (if any) have been for a different syntax which > could give a more streamlined syntax? > > > > My own thinking has been around an alternative to the cascade semicolon. > What symbol to use does not matter for me, but something like > > json at: âtree' Âº > > select: [ :e | ((e at: 'type') = 'blobâ)]Âº > > collect: [:e | Path from: (e at: 'pathâ)]Âº > > select: [ :p | p segments last > > in: [ :name | (name endsWith: '.md') | (name endsWith: > '.mic') ] ] > > > > Basically, a send the right hand expression to the result of the left > hand expression. > > > > Has anyone ever tried this, or is it just one of the many small > annoyances best left alone? > > > > Best, > > > > Kasper >

Jan. 26, 2022

Re: Too many parenthesis - a matter of syntax

by Esteban Maringolo

On Wed, Jan 26, 2022 at 10:58 AM gettimothy via Pharo-users <pharo-users(a)lists.pharo.org> wrote: > I realize this is just a preference, but the denseness forces me to think in Objects and composition rather than process. I never thought of it this way, but I fully agree with it. Thanks for putting this in words. Maybe what we need is better highlighting of the current "scope" where the cursor is. Navigating in and out of the parenthesis is not trivial, and it feels like hunting sometimes. With Futures it would be convenient to be able to link different #then: and such, but what you might need is a "chained" object that does all that for you. I always think of ways to improve the current syntax, but in the end it seems like anything else feels unnatural, and the net result is not positive. So... more objects, less syntax... and better tooling. Regards, Esteban A. Maringolo

Jan. 26, 2022

Re: Too many parenthesis - a matter of syntax

by gettimothy

Also...learning to think in Smalltalk has taught me to understand Lisp. As an Emacs guy, that is a good thing (:

Jan. 26, 2022

Re: Too many parenthesis - a matter of syntax

by gettimothy

I like the parenthesis. The thinking process is very much like "thinking in Sets" when building a complex SQLÂ statement. The result is a lot of power in an dense, elegant expression. If, as is often the case with me, I find a nested expression as below too complex, it is very easy to decompose it. I realize this is just a preference, but the denseness forces me to think in Objects and composition rather than process. just my .02 cents. cheers. ---- On Wed, 26 Jan 2022 04:19:39 -0500 Kasper Osterbye <kasper.osterbye(a)gmail.com> wrote ---- Cheers all I have noticed that I often ends up with quite a number of nested expressions, for example: (((json at: 'tree') Â Â Â Â select: [ :e | (e at: 'type') = âblob' ]) Â Â Â Â Â Â Â Â collect: [:e | Path from: (e at: 'path')]) Â Â Â Â Â Â Â Â Â Â Â Â select: [ :p | p segments last Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â in: [ :name | (name endsWith: '.md') | (name endsWith: '.mic') ] ] What kind of proposals (if any) have been for a different syntax which could give a more streamlined syntax? My own thinking has been around an alternative to the cascade semicolon. What symbol to use does not matter for me, but something like json at: âtree' Âº Â Â Â Â select: [ :e | ((e at: 'type') = 'blobâ)]Âº Â Â Â Â collect: [:e | Path from: (e at: 'pathâ)]Âº Â Â Â Â select: [ :p | p segments last Â Â Â Â Â Â Â Â in: [ :name | (name endsWith: '.md') | (name endsWith: '.mic') ] ] Basically, a send the right hand expression to the result of the left hand expression. Has anyone ever tried this, or is it just one of the many small annoyances best left alone? Best, Kasper

Jan. 26, 2022

Re: Too many parenthesis - a matter of syntax

by Sven Van Caekenberghe

Hi Kaspar, I found the initial example actually reasonable readable. However, I would simplify it as follows: (json at: #tree) select: [ :each | ((each at: #type) = #blob) and: [ #(md mic) includes: (Path from: (each at: #path)) extension ] ]. I would personally not try to extend the Smalltalk syntax. The cost is not worth the gain. Tools could be written to help in dealing with deeply nested structures (JSON/XML), they could form their own DSL at a higher level. For a limited example, NeoJSONObject uses the DNU trick to support unary accessors: json at: #tree can be written as json tree and has a path accessor: json atPath: #(tree field name) it also behaves like JavaScript objects in that missing keys are nil. It is not that all this is good or better, it is just handy in some cases. Your code would then be even simpler (less parenthesis): json tree select: [ :each | (each type = #blob) and: [ #(md mic) includes: (Path from: each path) extension ] ]. Sven > On 26 Jan 2022, at 10:19, Kasper Osterbye <kasper.osterbye(a)gmail.com> wrote: > > Cheers all > > I have noticed that I often ends up with quite a number of nested expressions, for example: > > (((json at: 'tree') > select: [ :e | (e at: 'type') = âblob' ]) > collect: [:e | Path from: (e at: 'path')]) > select: [ :p | p segments last > in: [ :name | (name endsWith: '.md') | (name endsWith: '.mic') ] ] > > What kind of proposals (if any) have been for a different syntax which could give a more streamlined syntax? > > My own thinking has been around an alternative to the cascade semicolon. What symbol to use does not matter for me, but something like > json at: âtree' Âº > select: [ :e | ((e at: 'type') = 'blobâ)]Âº > collect: [:e | Path from: (e at: 'pathâ)]Âº > select: [ :p | p segments last > in: [ :name | (name endsWith: '.md') | (name endsWith: '.mic') ] ] > > Basically, a send the right hand expression to the result of the left hand expression. > > Has anyone ever tried this, or is it just one of the many small annoyances best left alone? > > Best, > > Kasper

Jan. 26, 2022

Re: Too many parenthesis - a matter of syntax

by jtuchel＠objektfabrik.de

Kasper, I wouldn't say your suggestion looks any more readable than the many parentheses of the original expression. The whole operation is complex enough to be hard to understand. So I agree with both Richard and Sebastian - you should either make the steps readable by giving the intermediate results good names or factor the whole operation out into some object and good method name (which would be hard to read in itself without the temp vars, so you should pobably combine both suggestions). My opinion may be irrelevant, as I don't hold a "real" CS degree. I look at this from the perspective of the poor guy who has to debug this in three years rather than from an angle of elegance or conciseness. I guess even something like the .then() - syntax from Javascrpt wouldn't make this any more readable. And whatever symbol you'd chose it wouldn't communicate what's happening... Joachim Am 26.01.22 um 10:19 schrieb Kasper Osterbye: > Cheers all > > I have noticed that I often ends up with quite a number of nested expressions, for example: > > (((json at: 'tree') > select: [ :e | (e at: 'type') = âblob' ]) > collect: [:e | Path from: (e at: 'path')]) > select: [ :p | p segments last > in: [ :name | (name endsWith: '.md') | (name endsWith: '.mic') ] ] > > What kind of proposals (if any) have been for a different syntax which could give a more streamlined syntax? > > My own thinking has been around an alternative to the cascade semicolon. What symbol to use does not matter for me, but something like > json at: âtree' Âº > select: [ :e | ((e at: 'type') = 'blobâ)]Âº > collect: [:e | Path from: (e at: 'pathâ)]Âº > select: [ :p | p segments last > in: [ :name | (name endsWith: '.md') | (name endsWith: '.mic') ] ] > > Basically, a send the right hand expression to the result of the left hand expression. > > Has anyone ever tried this, or is it just one of the many small annoyances best left alone? > > Best, > > Kasper -- ----------------------------------------------------------------------- Objektfabrik Joachim Tuchel mailto:jtuchel@objektfabrik.de Fliederweg 1 http://www.objektfabrik.de D-71640 Ludwigsburg http://joachimtuchel.wordpress.com Telefon: +49 7141 56 10 86 0 Fax: +49 7141 56 10 86 1

Jan. 26, 2022