# Language Design Working Group

**URL:** https://forum.p4.org/c/p4-language-design/5.md

[Latest](https://forum.p4.org/latest.md) · [Categories](https://forum.p4.org/categories.md)

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## [About the Language Design Working Group category](https://forum.p4.org/t/about-the-language-design-working-group-category/34)

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**Author:** [@judysnow](https://forum.p4.org/u/judysnow)\
**Replies:** 0

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The Language Design Working Group oversees the P4 language specification. LDWG repository and wiki

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## [P4 16 Language design - why tables are not allowed to be updated from Data plane](https://forum.p4.org/t/p4-16-language-design-why-tables-are-not-allowed-to-be-updated-from-data-plane/783)

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**Author:** [@Svenzer](https://forum.p4.org/u/Svenzer)\
**Replies:** 13\
**Last updated:** [June 25, 2023, 6:51am UTC](https://forum.p4.org/t/p4-16-language-design-why-tables-are-not-allowed-to-be-updated-from-data-plane/783 "2023-06-25T06:51:15Z")

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Hey I was reading through P416 and P4Runtime specifications and was trying to understand the modification of tables - the look-up tables and not the table objects defined in the p4 program - and wanted to know/understan…

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## [Modifying a ParserState Node](https://forum.p4.org/t/modifying-a-parserstate-node/562)

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**Author:** [@mohxen](https://forum.p4.org/u/mohxen)\
**Replies:** 2\
**Last updated:** [December 4, 2022, 2:08am UTC](https://forum.p4.org/t/modifying-a-parserstate-node/562 "2022-12-04T02:08:06Z")

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Hi all, I want to modify a ParserState node in a new pass in frontend. I used preorder in IR::ParserState by using Transform. For example, for one node I have state parse\_udp { packet.extract\<udp\_t\>(hdr.udp); accept;} …

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## [Does the P4 plan to support the expression for backgroud thread？](https://forum.p4.org/t/does-the-p4-plan-to-support-the-expression-for-backgroud-thread/255)

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**Author:** [@glinuxer](https://forum.p4.org/u/glinuxer)\
**Replies:** 4\
**Last updated:** [March 3, 2022, 12:11am UTC](https://forum.p4.org/t/does-the-p4-plan-to-support-the-expression-for-backgroud-thread/255 "2022-03-03T00:11:05Z")

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Now the P4 could set the entry timeout, but it’s enough for ip fragment when dataplane want to reassemble the frags. It has to send the fragments to control cpu to hold the frags until assemble or timeout. So I want to …