On Aug 18, 2019, at 3:03 PM, Levente Uzonyi <leves@caesar.elte.hu> wrote:

Hi Nicolas,

Thanks for investigating this.
I still think that it's just a parser bug, which is accidentally "used" sometimes, especially because it only works when the block is empty.
Or does it work in other dialects with non-empty blocks?
Is it used in other dialects?

Levente

On Sun, 18 Aug 2019, Nicolas Cellier wrote:

Le jeu. 15 août 2019 à 12:21, Levente Uzonyi <leves@caesar.elte.hu> a écrit :
     On Thu, 15 Aug 2019, Tobias Pape wrote:

     >
     >> On 15.08.2019, at 03:29, Levente Uzonyi <leves@caesar.elte.hu> wrote:
     >>
     >> On Wed, 14 Aug 2019, commits@source.squeak.org wrote:
     >>
     >>> A new version of ShoutCore was added to project The Inbox:
     >>> http://source.squeak.org/inbox/ShoutCore-ct.69.mcz
     >>>
     >>> ==================== Summary ====================
     >>>
     >>> Name: ShoutCore-ct.69
     >>> Author: ct
     >>> Time: 14 August 2019, 10:43:04.7164 pm
     >>> UUID: 7d165f4e-09bf-a445-a664-5e8edb9867b8
     >>> Ancestors: ShoutCore-ul.68
     >>>
     >>> Fix bug in SHParserST80: Wrong styling after blocks with arguments without statements
     >>
     >> If you mean that Shout should accept [ :x ], then no, I'm pretty sure that's not valid smalltalk syntax, even if Parser accepts it.
     >> The vertical bar, even though I consider it unnecessary in all cases, is mandatory when there are arguments.
     >
     > I only got to know this "shortcut syntax" because eliot used it either Cog or somewhere in trunk when preparing something (Spur? full block closures? I forgot). So this is a syntax idiosyncrasy that is in active use, not only "old code".
     >
     > Either we forbid it in the parser and change all of the image or allow it in Shout.

     Can you give me examples?
     I suspect those are just typos, which the parser accidentally accepted
     (and Shout as well before my fixes).

     Levente
I don't remember seeing this syntax before and found it a bit surprising.
So, for the sake of curiosity, I tried in some other dialects.
[:x ] is accepted syntax in
- Visualworks (8.3),
- Pharo (v7 with OpalCompiler)
- Smalltalk-80 (apple v0.?)
[:x ] is invalid in
- Dolphin
- Smalltalk/X (jv branch)
So it seems that it's something originating from original Smalltalk-80, but not reproducted in non derivated dialects...
The bar is mandatory in blue book specification (see the last pages)
Capture d’écran 2019-08-18 à 17.11.53.png
So it seems that implementation did not agree with specifications for ages...
Capture d’écran 2019-08-18 à 18.56.05.png

     >
     > Best regards
     >       -Tobias
     >
     >>
     >> Levente
     >>
     >>>
     >>> Thanks Jakob for the report!
     >>>
     >>> =============== Diff against ShoutCore-ul.68 ===============
     >>>
     >>> Item was changed:
     >>> ----- Method: SHParserST80>>parseBlockArguments (in category 'parse') -----
     >>> parseBlockArguments
     >>>
     >>>     currentTokenFirst == $: ifFalse: [ ^self ].
     >>>     [ currentTokenFirst == $: ] whileTrue: [
     >>>             self
     >>>                     scanPast: #blockArgColon;
     >>>                     parseArgument: #blockPatternArg ].
     >>> +   ((self parseVerticalBarForTemporaries: #blockArgsBar) and: [
     >>> +           currentTokenFirst ~= $] ])
     >>> +                   ifFalse: [
     >>> +                           self fail ": Missing block args bar" ]!
     >>> -   (self parseVerticalBarForTemporaries: #blockArgsBar) ifFalse: [
     >>> -           self fail ": Missing block args bar" ]!
     >>