Tx thierry I will check and make some experiments.
On Sat, Apr 1, 2017 at 9:45 PM, Thierry Goubier <thierry.goub...@gmail.com>
wrote:
>
>
> Le 01/04/2017 à 19:31, Stephane Ducasse a écrit :
>
>> Hi
>>
>> I'm trying to understand what are the idioms in Smacc when converting from
>> ANTLR
>>
>> ######### the case of * ########################
>> Function = ‘(‘ (',' Arguments )* ‘)’
>>
>
> Function: "(" ( Argument ("," Argument) * ) ? ")" {{}} ;
>
> Argument: <identifier> 'argument' ;
>
> This one in SmaCC github, gives you exactly what you want (a Function ast
> node with an instance variable named arguments containing a possibly empty
> list of arguments) and is equivalent to your transform below.
>
> Even more concise; one can put the instance variable name in the top-level
> expression, and SmaCC will infer the list behavior:
>
> Function: "(" (Expression 'argument' ("," Expression 'argument')*)? {{}} ;
>
> should be transformed into
>>
>> Function
>> : <name> "(" 'leftParen' _ArgumentsOption ")" 'rightParen' {{}}
>> ;
>> _ArgumentsOption
>> :
>> | Arguments
>> ;
>> Arguments
>> : Expression 'argument'
>> | Arguments "," Expression 'argument'
>> ;
>>
>> Here since there is a recursion in Arguments
>> the instance variable containing a list of argument will be added to the
>> FunctionNode
>> Pay attention that Expression 'argument' should not have a {{}} nor its
>> parent rule.
>>
>>
>> ######### the case of + ########################
>> Function = ‘(‘ Arguments + ‘)’
>>
>
> Function: "(" Argument 'argument' ("," Argument 'argument') * ")";
>
> Argument: <identifier> ;
>
> should be transformed into
>>
>> Function
>> : <name> "(" 'leftParen' _ArgumentsOption ")" 'rightParen' {{}}
>> ;
>> _ArgumentsOption
>> : Arguments
>> ;
>> Arguments
>> : Expression 'argument'
>> | Arguments "," Expression 'argument'
>> ;
>>
>>
>>
>> ######### the case of ? ########################
>> Function = ‘(‘ Arguments+ ‘)’
>>
>
> Function = '(' Arguments? ')', that is:
>
> Function: "(" (Arguments 'argument') ? ")";
>
> You need the parenthesis here. This is a bug, it should accept
>
> Function: "(" Arguments 'argument' ? ")" ;
>
> I'll add an issue and improve the SmaCC grammar grammar.
>
>
>> should be transformed into
>>
>> Function
>> : <name> "(" 'leftParen' _ArgumentsOption ")" 'rightParen' {{}}
>> ;
>> _ArgumentsOption
>> :
>> | Arguments
>> ;
>> Arguments
>> : Expression 'argument'
>> ;
>>
>>
>>
>> Is there a more compact way to express?
>>
>
> With +, *, ? and () of course :)
>
> Thierry do you have example of *, + , ? in the grammar?
>>
>
> No, not that many. I did not use them much professionally, and then I
> didn't make the effort to check that the AST annotations would work
> correctly with them, so I had a tendancy to remove them.
>
> This is the first time I'm really checking that annotations work properly
> over those syntax extensions.
>
> The initial (1.X) version of thoses annotations were not compatibles with
> the AST annotations, so I had back then to hack the SmaCC 2.0.3 base to
> support them, without having the time to check it was done properly on the
> annotation level.
>
> Thierry
>
> Stef
>>
>
>
>
