Talk:Recursive grammar

This article was nominated for deletion on 29 March 2013 (UTC). The result of the discussion was speedy keep.

Computing Low‑importance

	This article is within the scope of WikiProject Computing, a collaborative effort to improve the coverage of computers, computing, and information technology on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.ComputingWikipedia:WikiProject ComputingTemplate:WikiProject ComputingComputing articles
Low	This article has been rated as Low-importance on the project's importance scale.

Computer science Low‑importance

This article is within the scope of WikiProject Computer science, a collaborative effort to improve the coverage of Computer science related articles on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.Computer scienceWikipedia:WikiProject Computer scienceTemplate:WikiProject Computer scienceComputer science articles

Low

This article has been rated as Low-importance on the project's importance scale.

Things you can help WikiProject Computer science with:

Here are some tasks awaiting attention:

Article requests :
- Requested articles/Applied arts and sciences/Computer science, computing, and Internet
Cleanup :
- Computer science articles needing attention
- Computer science articles needing expert attention
Copyedit :
- Computing
Expand :
- Computer science
Infobox :
- Computer science articles without infoboxes
Maintain :
- Timeline of computing 2020–present
Photo :
- Find pictures for the biographies of computer scientists (see List of computer scientists)
- Computing articles needing images
Stubs :
- Computer science stubs
Unreferenced :
- WikiProject Computer science/Unreferenced BLPs
Project-related :
- Tag all relevant articles in Category:Computer science and sub-categories with {{WikiProject Computer science}}

Cognitive science (inactive)

This article is within the scope of WikiProject Cognitive science, a project which is currently considered to be inactive.Cognitive scienceWikipedia:WikiProject Cognitive scienceTemplate:WikiProject Cognitive scienceCognitive science articles

erhm

Another more obvious meaning would be for recursive instead of recursively enumerable languages. The current def is not actually cited. JMP EAX (talk) 09:23, 17 August 2014 (UTC)[reply]

What does it mean "if it contains production rules that are recursive"? Is S -> aSa recursive? Perhaps so. What about the grammar with two rules A -> aB and B -> Aa? JMP EAX (talk) 09:38, 17 August 2014 (UTC)[reply]

Also, the concept of leftmost derivation is not well defined above CFGs. JMP EAX (talk) 09:33, 17 August 2014 (UTC)[reply]

I see the this is another article "saved" at AfD by doing partial string matches versus random sources. JMP EAX (talk) 10:13, 17 August 2014 (UTC)[reply]

I first found the article when a wrong link in the Template:Formal languages and grammars had to be fixed: in line "Type-0, col. "Grammars", recursive grammar had to be corrected to unrestricted grammar; cf. Template_talk:Formal_languages_and_grammars#Removing "recursive grammar".

I considered to suggest the article recursive grammar for deletion, but changed my mind as it is of somewhat use at the lower end of the language hierarchy (cf. bottom line of the template, non-recursive grammar redirects to recursive grammar).

To define non-recursion formally, a strict partial order on the set of non-terminals would be required such that in each rule, each non-terminal on the lhs is strictly larger than each one on its rhs. Maybe, however, that notion doesn't make sense for grammars beyond context-free ones. - Jochen Burghardt (talk) 12:22, 17 August 2014 (UTC)[reply]

Except we want a reliable source to actually give this def and call it this, otherwise it's WP:OR. JMP EAX (talk) 13:40, 17 August 2014 (UTC)[reply]