[Cuis-dev] extending the syntax for blocks and methods

[stephen at heaveneverywhere.com]

I’ve seen several systems that override @ in connection classes to be at:, but the syntax

> a @ i := b @ i

would require non-trivial parser/compiler hacks.  Perhaps use @: for at :put: as in a @ 3 : 0  ?

stp


--

                    Stephen Travis Pope   Ojai, California, USA    
          http://HeavenEverywhere.com <http://heaveneverywhere.com/>        http://FASTLabInc.com <http://fastlabinc.com/>
                       https://vimeo.com/user19434036/videos <https://vimeo.com/user19434036/videos>      http://heaveneverywhere.com/Reflections

--




> On Jul 17, 2022, at 2:40 PM, Francisco Garau via Cuis-dev <cuis-dev at lists.cuis.st> wrote:
> 
> Dan Ingalls talks about the indexing operator in "The evolution of Smalltalk: from Smalltalk-72 through Squeak" [1]
> In Smalltalk--76
> a • i ← b • i
> In Smalltalk--80
> a at: i put: (b at: i)
> Smalltalk--80--didnahappen
> a @ i := b @ i
> or
> a ! i := b ! i
> 
> [1] http://worrydream.com/refs/Ingalls%20-%20The%20Evolution%20of%20Smalltalk.pdf <http://worrydream.com/refs/Ingalls%20-%20The%20Evolution%20of%20Smalltalk.pdf>
> 
> On 16 Jul 2022, at 10:51, Luciano Notarfrancesco <luchiano at gmail.com <mailto:luchiano at gmail.com>> wrote:
> 
>> Hola!
>> Interesting. Actually methods written like this look more complicated than the original Smalltalk-80 syntax to me, but it’s an interesting idea, maybe looks complicated just because I’m not used to it. Let us know how it goes.
>> 
>> Note that in Cuis #: is a valid binary message. I use it, maybe I’m the only one who uses it.
>> 
>> Another idea we discussed before was to compile ‘f(x)’ as ‘f value: x’. Note that this is not ambiguous with Smalltalk-80. We could also compile ‘a[i]’ as ‘a at: i’. I’m not sure if it’s worth to complicate the Smalltalk-80 syntax with things like this, tho, I also value simplicity.
>> 
>> 
>> On Sat, 16 Jul 2022 at 01:39 Francisco Garau via Cuis-dev <cuis-dev at lists.cuis.st <mailto:cuis-dev at lists.cuis.st>> wrote:
>> Hola Amigos -- just wanted to share with you some ideas I've been thinking about for a while. 
>> 
>> It all started when someone mentioned the colon in the syntax for block arguments could have whitespace around the argument so that you could write  [ : n | n + 1] 
>> 
>> It makes perfect sense to see the block as an "inlined" method that doesn't require any method-lookup; therefore, the selector is superfluous. But if we accepted the selector inside the block, it could be used as the variable holding the block. So, instead of writing succ := [:n | n + 1]  we could write  [succ: n | n + 1]  
>> 
>> Even better if the block evaluation accepts #: as a valid selector.  So you could write (succ: 3) = 4 instead of (succ value: 3) = 4. 
>> 
>> A short example will make this clear. 
>> 
>> Vanilla Smalltalk
>> succ := [:n | n + 1].
>> (succ value: 3) = 4. 
>> 
>> Extended Block Syntax
>> [succ: n | n + 1]. 
>> (succ: 3 ) = 4. 
>> "the above is equivalent to" 
>> (succ perform: #: with: 3) = 4. 
>> 
>> Being able to parse blocks with these syntax paves the way to unify the syntax for method definition—for example, a few hypothetical methods from the Point class. 
>> 
>> "Point class>x:y:" 
>> [x: xInteger y: yInteger | 
>>    ^self basicNew setX: xInteger setY: yInteger].
>> 
>> "Point>>abs"
>> [abs | 
>>    ^x abs @ y abs]. 
>> 
>> "Point>>extent:" 
>> [extent: aPoint |
>>    ^Rectangle origin: self extent: aPoint] 
>> 
>> Of course, it gets trickier when blocks have more than one argument.. 
>> 
>> [add: a to: b | a + b]. 
>> (add_to value: 3 value: 4) = 7. "old style block evaluation" 
>> (add: 3 to: 4) = 7. 
>> 
>> I think building a separate Parser is a sensible approach -- is there a Smalltalk Parser as a separate package that can be tweaked without affecting the running image?
>> 
>> Thanks,
>> Francisco
>> 
>> 
>> -- 
>> Cuis-dev mailing list
>> Cuis-dev at lists.cuis.st <mailto:Cuis-dev at lists.cuis.st>
>> https://lists.cuis.st/mailman/listinfo/cuis-dev <https://lists.cuis.st/mailman/listinfo/cuis-dev>
> -- 
> Cuis-dev mailing list
> Cuis-dev at lists.cuis.st
> https://lists.cuis.st/mailman/listinfo/cuis-dev

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.cuis.st/mailman/archives/cuis-dev/attachments/20220717/2f5692a2/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: pastedGraphic.tiff
Type: image/tiff
Size: 2442 bytes
Desc: not available
URL: <http://lists.cuis.st/mailman/archives/cuis-dev/attachments/20220717/2f5692a2/attachment-0001.tiff>