[squeak-dev] The Inbox: ShoutCore-ct.69.mcz
JOHN SARKELA
wiljo at mac.com
Sun Aug 18 19:09:56 UTC 2019
The ANSI standard has the following rules for blocks:
<block constructor> ::= '[' <block body> ']'
<block body> ::= [<block argument>* '|'] [<temporaries>] [<statements>]
The standard does not recognize [:x] as legal syntax for a block.
> On Aug 18, 2019, at 3:03 PM, Levente Uzonyi <leves at caesar.elte.hu <mailto:leves at 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 at caesar.elte.hu <mailto:leves at caesar.elte.hu>> a écrit :
>> On Thu, 15 Aug 2019, Tobias Pape wrote:
>>
>> >
>> >> On 15.08.2019, at 03:29, Levente Uzonyi <leves at caesar.elte.hu <mailto:leves at caesar.elte.hu>> wrote:
>> >>
>> >> On Wed, 14 Aug 2019, commits at source.squeak.org <mailto:commits at source.squeak.org> wrote:
>> >>
>> >>> A new version of ShoutCore was added to project The Inbox:
>> >>> http://source.squeak.org/inbox/ShoutCore-ct.69.mcz <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" ]!
>> >>
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