[cocci] Collateral evolution because of context-dependent grammar of SmPL?

[cocci] Collateral evolution because of context-dependent grammar of SmPL?

[Markus Elfring]

Hello,

I have taken another look at details from the grammar of the semantic patch language
(Coccinelle software).
I interpret the SmPL script programming structure in the way that optional header
information can be specified before the main data processing part.
https://gitlab.inria.fr/coccinelle/coccinelle/-/blob/5479fc964d209209e84ddd5caf3f395667721e7c/docs/manual/cocci_syntax.tex#L31
https://github.com/coccinelle/coccinelle/blob/ae337fce1512ff15aabc3ad5b6d2e537f97ab62a/docs/manual/cocci_syntax.tex#L31

The main part usually contains some SmPL rules.
Each SmPL rule is split into two sections.

1. The beginning and end of the metavariable declaration block is denoted by
   a pair of @ characters.
   Additional settings can be specified also within the first pair of @ characters.

2. Code from supported scripting and programming languages can be specified for
   desired analyses and transformations.
   @ operators can be applied for the combination of metavariables
   as they would be needed for selected data processing tasks.


I got the impression that such characteristics result in the classification
that the grammar of the semantic patch language is context-dependent.

Something was achieved by the application of the software tool “Menhir”.
http://gallium.inria.fr/~fpottier/menhir/

This parser generator for the OCaml programming language is using the technique “LR(1)”.

The Chomsky–Schützenberger hierarchy denotes some computational properties
for such language categories.
https://en.wikipedia.org/wiki/Context-sensitive_language#Computational_properties

Advices were published that context-dependent grammars should safely be handled
by more sophisticated parsing technologies.
https://en.wikipedia.org/wiki/Comparison_of_parser_generators#Context-sensitive_grammars

How do you think about to clarify corresponding design challenges any further?

Regards,
Markus

Re: [cocci] Collateral evolution because of context-dependent grammar of SmPL?

[Julia Lawall]

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On Sat, 12 Mar 2022, Markus Elfring wrote:

> Hello,
>
> I have taken another look at details from the grammar of the semantic patch language
> (Coccinelle software).
> I interpret the SmPL script programming structure in the way that optional header
> information can be specified before the main data processing part.
> https://gitlab.inria.fr/coccinelle/coccinelle/-/blob/5479fc964d209209e84ddd5caf3f395667721e7c/docs/manual/cocci_syntax.tex#L31
> https://github.com/coccinelle/coccinelle/blob/ae337fce1512ff15aabc3ad5b6d2e537f97ab62a/docs/manual/cocci_syntax.tex#L31
>
> The main part usually contains some SmPL rules.
> Each SmPL rule is split into two sections.
>
> 1. The beginning and end of the metavariable declaration block is denoted by
>    a pair of @ characters.
>    Additional settings can be specified also within the first pair of @ characters.
>
> 2. Code from supported scripting and programming languages can be specified for
>    desired analyses and transformations.
>    @ operators can be applied for the combination of metavariables
>    as they would be needed for selected data processing tasks.
>
>
> I got the impression that such characteristics result in the classification
> that the grammar of the semantic patch language is context-dependent.
>
> Something was achieved by the application of the software tool “Menhir”.
> http://gallium.inria.fr/~fpottier/menhir/
>
> This parser generator for the OCaml programming language is using the technique “LR(1)”.
>
> The Chomsky–Schützenberger hierarchy denotes some computational properties
> for such language categories.
> https://en.wikipedia.org/wiki/Context-sensitive_language#Computational_properties
>
> Advices were published that context-dependent grammars should safely be handled
> by more sophisticated parsing technologies.
> https://en.wikipedia.org/wiki/Comparison_of_parser_generators#Context-sensitive_grammars
>
> How do you think about to clarify corresponding design challenges any further?

The parser has different entry points according to the context.

julia

Re: [cocci] Collateral evolution because of context-dependent grammar of SmPL?

[Markus Elfring]

>> Advices were published that context-dependent grammars should safely be handled
>> by more sophisticated parsing technologies.
>> https://en.wikipedia.org/wiki/Comparison_of_parser_generators#Context-sensitive_grammars
>>
>> How do you think about to clarify corresponding design challenges any further?
> The parser has different entry points according to the context.


Would you like to share any more background information for such entry points?

Regards,
Markus