Well... you have the cascading that provides you that. book1 title:'C Programming'; author: 'Nuha Ali '; subject: 'C Programming Tutorial'; book_id: 6495407. What I would like, sometimes, is the option to nest cascades, very much like the WITH DO construct of Pascal, Basic and others. But also I take this as a hint of some refactoring needed in my objects. Regards, Esteban A. Maringolo El lun., 4 mar. 2019 a las 10:07, Tim Mackinnon (<tim@testit.works>) escribió:

I’ve noticed that as we’ve progressed there has been a move to more concise and fluid code - e.g. I quite like the new String streaming stuff

e.g.

^ String streamContents: [ :stream | stream nextPut: …. ]

So I was wondering why we don’t have a construct like Pascals with to avoid Book1.title, Book1.author etc.

(* book 1 specification *) With Book1 do begin title := 'C Programming'; author := 'Nuha Ali '; subject := 'C Programming Tutorial'; book_id := 6495407; end;

I often find it a bit tedious with code like the following which then needs an instvar...

self classes do: [ :class | | metaclass | metaclass := class metaclass. metaclass xxxx. mataclass yyyy. ]

I’m wondering why we don’t have #with:do:

class with: class metaclass do: [:metaclass | metaclass xxx. ]

But when such things aren’t there - there is usually a good reason and I’m curious … this said, there are all kinds of other such tricks (which I rarely use that I keep coming across).

Tim

There is #in: that does exactly that: class metaclass in: [ :metaclass | metaclass xxx. metaclass yyy ]. This is quite similar to lisp's let. You can do almost anything with blocks/closures. Although not relevant in most cases, there is a small performance price to pay - but again this is only relevant inside performance critical loops.

On 4 Mar 2019, at 14:06, Tim Mackinnon <tim@testit.works> wrote:

I’ve noticed that as we’ve progressed there has been a move to more concise and fluid code - e.g. I quite like the new String streaming stuff

e.g.

^ String streamContents: [ :stream | stream nextPut: …. ]

So I was wondering why we don’t have a construct like Pascals with to avoid Book1.title, Book1.author etc.

(* book 1 specification *) With Book1 do begin

title := 'C Programming';

author := 'Nuha Ali ';

subject := 'C Programming Tutorial';

book_id := 6495407; end;

I often find it a bit tedious with code like the following which then needs an instvar...

self classes do: [ :class | | metaclass | metaclass := class metaclass. metaclass xxxx. mataclass yyyy. ]

I’m wondering why we don’t have #with:do:

class with: class metaclass do: [:metaclass | metaclass xxx. ]

But when such things aren’t there - there is usually a good reason and I’m curious … this said, there are all kinds of other such tricks (which I rarely use that I keep coming across).

Tim

The Pascal 'with' statement is among the most hated features of Pascal and was not copied in successor languages like Ada or Modula-2. It was typically replaced by record constructors, such as Book1 := Book[title : 'C Programming'; author : 'Nuha Ali '; subject : 'C Programming Tutorial'; book_id : 6495407]; which happens to be Pascal (ISO10206). In self classes do: [:class | | metaclass | metaclass := class metaclass. metaclass xxxx. mataclass yyyy. ] "metaclass" is a a block temporary, not an instance variable, and self classes do: [:each | (each metaclass) xxxx; yyyy]. suffices. We observe that [:x1 ... :xn | ...] value: e1 ... value: en is nothing other than a LET expression wearing a funny hat and should be inlined by a compiler -- mine does -- and that e1 in: [:x1 | ...] is just a "flipped" version of [:x1 | ...] value: e1, so there's no reason why a compiler shouldn't inline that. We also observe that e0 m1; ... ; mn can -- at least in my experience -- be most simply implemented as [:t | t m1. ... t mn] value: e0 followed by the usual inlining of that. So we might expect that some day self classes do: [:each | each metaclass in: [:t | t xxxx. t yyyy]] would generate the *same* code as the cascaded version. Right now, do whichever is clearer. On Tue, 5 Mar 2019 at 02:07, Tim Mackinnon <tim@testit.works> wrote:

I’ve noticed that as we’ve progressed there has been a move to more concise and fluid code - e.g. I quite like the new String streaming stuff

e.g.

^ String streamContents: [ :stream | stream nextPut: …. ]

So I was wondering why we don’t have a construct like Pascals with to avoid Book1.title, Book1.author etc.

(* book 1 specification *)With Book1 dobegin title := 'C Programming'; author := 'Nuha Ali '; subject := 'C Programming Tutorial'; book_id := 6495407;end;

I often find it a bit tedious with code like the following which then needs an instvar...

self classes do: [ :class | | metaclass | metaclass := class metaclass. metaclass xxxx. mataclass yyyy. ]

I’m wondering why we don’t have #with:do:

class with: class metaclass do: [:metaclass | metaclass xxx. ]

But when such things aren’t there - there is usually a good reason and I’m curious … this said, there are all kinds of other such tricks (which I rarely use that I keep coming across).

Tim