Talk:Regular language
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I removed the following:
- The word regular is used because these expressions are built up using very distinct limited and regulated syntax rules.
I think one could argue that context-free languages are also built according to limited syntax rules. I'm pretty sure the word "regular" was chosen without much thinking; it's one of those meaningless terms, like "normal", that are used all over the place. Also, the above "these expressions" seems to refer to regular expressions, but regular expressions hadn't been mentioned in the article at that point. --AxelBoldt
A regular language is a formal language (i.e. a possibly infinite set of finite sequences of symbols from a finite alphabet) that has one of the following equivalent properties:
- (...)
- it can be described by a regular expression.
Modern "regular" expressions can describe more languages than just regular ones. Example: /([a-z]*)\\1/ (weird software problem - there should be 1 backslash there) --Taw
- Obviously, this refers to regular expressions in the sense used in the theory of computation, not Perl regular expressions etc. -- Schnee 12:16, 13 Jun 2004 (UTC)
I'm reading about regular languages for the first time, so am curious about few things which I could not find in the article.
- Why the word 'regular' ? I can see a line on this talk page about it, but it'd be good if a line is added to the main article as well.
- Examples of some regular languages
- What do you call a language thats not a regular language. An "irregular language" ? If there is anything of the sort, a link to it and maybe an example would help understand this article better.
Jay 07:48, 14 Nov 2003 (UTC)
- An example of a regular language might be that consisting of all words formed by three a's followed by any number of b's (with the alphabet consisting of a and b). I don't know where the term "regular" comes from, but I guess it's historic; as for non-regular languages, I never heard of a special moniker for them (outside of "non-regular"). -- Schnee 12:16, 13 Jun 2004 (UTC)
'# it can be accepted by a deterministic finite state machine.' is superfluous. Every NFA has an equivalent DFA. So by requiring a regular language to be accepted by an NFA requires it to be accepted by a (the corrisponding DFA)
- That's not superfluous. All the properties listed are equivalent, after all, and to the uninitiated, it's not obvious that DFAs and NFAs are basically the same. -- Schnee 12:16, 13 Jun 2004 (UTC)
This article describes the properties of regular languages and gives a few examples, but I think a kind of formal definition was missing. I added a well-known recursive definition. I think it fits pretty well in the article. What do you think? --Alexandre 22:27, 25 Jun 2004 (UTC)