指定语法的语言
是否有任何特定的方法来指定给定语法的语言？即是否有必要运行语法中给出的所有产生式规则来确定它所代表的语言？我没有这样的例子，因为我正在研究的是一个家庭作业问题。
[edit]: adding an example, Describe, in English, the language defined by the grammar
<S> -> <A> <B> <C>
<A> -> a <A> | a
<B> -> b <B> | b
<C> -> c <C> | c
问候，
黑暗 15
Is there any specific methodology followed to specify a language for given grammar ?? i.e. Is it necessary to run all the production rules given in a grammar to determine the language it represents? I don't have an example as such since the one I am working on is a homework question.
[edit]: adding an example, Describe, in English, the language defined by the grammar
<S> -> <A> <B> <C>
<A> -> a <A> | a
<B> -> b <B> | b
<C> -> c <C> | c
Regards,
darkie15
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在您的示例中，该部分
完全识别
a的非空列表其他两个产生式
和b和c.因此，用
->，您可以推断此语法识别的语言是a的任何非空列表，后跟b的非空列表，然后是 ac的非空列表，对应正则表达式a+b+c+。从那里可以很容易地证明正则表达式识别的每个实例都可以使用归纳法被语法识别。
In you example, the part
recognizes exactly non empty lists of
aThe same goes for the two other productions,
<B>and<C>, with respectivelybandc.Thus, with
<S> -> <A> <B> <C>, you deduce that the language this grammar recognizes is any non empty list ofa, followed by a non empty list ofb, then a non empty list ofc, corresponding to the regular expressiona+b+c+.Proof is quite easy from there to show that each instance recognized by the regular expression is recognized by the grammar, using induction.