Talk:Regular grammar

message: I have taken the liberty to disntnguish between right regular grammars and left regular grammars more clearly -- rp, mar 09 2004
It would be nice to give a sense of what (N, Σ, P, S) are without sending readers immediately to Formal_grammar. Is there a way to do this that would make sense? Jodi.a.schneider 04:01, 10 October 2006 (UTC)

message: If you allow the empty rhs, so A → ε, you do not need the form A → a, since you can add a non-terminal E → ε and then use the rule A → aE.
So, having form A → a along A → aB makes only sense if you restrict the empty rhs to the start symbol, meaning S → ε.
I suggest to refine the definitions (or, if not wished, explain their redundancy clearly). Andreasabel (talk) 18:49, 22 February 2023 (UTC)
replies: text: I think you will find that definitions vary. Some authors don't allow empty productions at all. Rp (talk) 07:42, 23 February 2023 (UTC)

text: I think we should mention the most typical definition variants of regular grammars, so if you can provide a citation (textbook preferred) about your variant, please provide it here, or insert an appropriate remark directly into the article. Currently, only the "extended" version by Hopcroft+Ullman 1979 is sourced. - Jochen Burghardt (talk) 11:47, 23 February 2023 (UTC)
thread_title:  Redundancy in definition of left/right regular grammar 

message: On some books left regular grammar is defined as below
A → a* - where A is a non-terminal in N and a is a terminal in Σ 
A → Ba* - where A and B are in N and a is in Σ 
However in Wikipedia the definition has excluded the possibility of having more than one terminals on the right hand side of the production. Why is this difference?
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For what I know there is no real difference: the grammars showed on the page are "strongly" (or "strictly") linear, while the ones you report are just linear (even if the way you wrote them is not so clear to me, because if you write a* it could mean "0 or more instances of the same symbol (the one which 'a' refers to)", and that wouldn't mean "regular" because it could produce an infinite sequence: in BNF you would use recursion to mean that, and you'd get something like A → B A for the second rule, which makes the grammar absolutely not regular).
From a linear grammar you can always get its strictly linear equivalent by substituting the non-strict rules with sets of rules each of which produce at most a terminal symbol (i.e., each rule does only one step).
Sorry for my English, anyway... and if I said something wrong let me know! :-)
--Ma82 12:12, 2 September 2006 (UTC)
thread_title:  Regular Grammar 

message: I just tripped over the article prefix grammar, which is almost nearly a left regular grammar, but not quite. I think that a prefix grammar can be described so that its isomorphic to a left regular grammar, but I'm not expert enough to try to guess how, off the top of my head. Clarification in both articles would be appreciated. linas 21:07, 21 April 2007 (UTC)
thread_title:  [[prefix grammar]] 

message: This rule set requires at least one digit after the dot, should the dot occur. Not every programming language disallows "3." as a valid floating point number (though none that I know of allow ".e0", but many might allow "0.e0" or ".0e0" or both). It wouldn't hurt for the example to comment on the assumptions underlying the floating-point language recognized. — MaxEnt 03:20, 13 April 2018 (UTC)
thread_title:  Floating point example 

message: The example (section) really isn’t one. It’s just more abstract theory and non-descriptive single-letter symbol walls.
How about a real-world example of a simple regular grammar. (Are globbing patterns a regular grammar?)
As almost always on Wikipedia, the article is completely obfuscated and incomprehensible to everyone except those who already know the subject better than the author. ^^
— 109.42.178.250 (talk) 21:08, 5 February 2024 (UTC)
thread_title:  In desperate need of a practical expample.