英文字典中文字典


英文字典中文字典51ZiDian.com



中文字典辞典   英文字典 a   b   c   d   e   f   g   h   i   j   k   l   m   n   o   p   q   r   s   t   u   v   w   x   y   z       







请输入英文单字,中文词皆可:

BNF    
巴科斯范式

巴科斯范式

{Backus-Naur Form}. Originally Backus Normal Form.

[{Jargon File}]

Backus-Naur Form (TTCN, ...)

BNF: /B·N·F/, n. 1. [techspeak] Acronym for Backus Normal
Form (later retronymed to Backus-Naur
Form because BNF was not in fact a normal form), a metasyntactic
notation used to specify the syntax of programming languages, command sets,
and the like. Widely used for language descriptions but seldom documented
anywhere, so that it must usually be learned by osmosis from other hackers.
Consider this BNF for a U.S. postal address:


 <postal-address> ::= <name-part> <street-address> <zip-part>



 <personal-part> ::= <name> | <initial> "."



 <name-part> ::= <personal-part> <last-name> [<jr-part>] <EOL>

               | <personal-part> <name-part>



 <street-address> ::= [<apt>] <house-num> <street-name> <EOL>



 <zip-part> ::= <town-name> "," <state-code> <ZIP-code> <EOL>

This translates into English as: “A postal-address consists of
a name-part, followed by a street-address part, followed by a zip-code
part. A personal-part consists of either a first name or an initial
followed by a dot. A name-part consists of either: a personal-part
followed by a last name followed by an optional jr-part (Jr., Sr., or
dynastic number) and end-of-line, or a personal part followed by a name
part (this rule illustrates the use of recursion in BNFs, covering the case
of people who use multiple first and middle names and/or initials). A
street address consists of an optional apartment specifier, followed by a
street number, followed by a street name. A zip-part consists of a
town-name, followed by a comma, followed by a state code, followed by a
ZIP-code followed by an end-of-line.” Note that many things (such as
the format of a personal-part, apartment specifier, or ZIP-code) are left
unspecified. These are presumed to be obvious from context or detailed
somewhere nearby. See also parse.


请选择你想看的字典辞典:
单词字典翻译
BNF查看 BNF 在百度字典中的解释百度英翻中〔查看〕
BNF查看 BNF 在Google字典中的解释Google英翻中〔查看〕
BNF查看 BNF 在Yahoo字典中的解释Yahoo英翻中〔查看〕





安装中文字典英文字典查询工具!


中文字典英文字典工具:
选择颜色:
输入中英文单字

































































英文字典中文字典相关资料:


  • BNF范式(巴科斯范式)到底是什么? - 知乎
    最著名的文法描述形式是由Backus定义 Algol60 语言时提出的 Backus-Naur范式 (Backus-Naur Form, BNF)及其扩展形式 EBNF 。BNF能以一种简洁、灵活的方式描述语言的语法。具体内容可参考针对编译原理的书。
  • Good BNF grammar tutorial introduction for a beginner?
    What's your tip for an introduction to BNF grammar (and how to use them in practice)? Something concise with many examples would be great Have been googling but only found enormously long artcles with unclear examples so far : (In my particular case, I'm trying to parse the Galaxy Toolconfig syntax, which includes if else statements etc )
  • syntax - Bracket and brace usage in BNF? - Stack Overflow
    @JonathanLeffler I assume the dialect of BNF is the most basic, academic dialect of BNF, since my text only covers BNF and EBNF and doesn't specify any particular dialect of BNF This is why I assumed braces brackets can't be used in "BNF" in this context I believe the parenthesis is a literal, it isn't explicitly stated though –
  • notation - How can I write a sentence in BNF? - Stack Overflow
    What is the syntax for writing a sentence in BNF? Backus-Naur form (BNF) isn't a data format like JSON or PDF, it's a description of the grammar that defines a given format You wouldn't write a sentence in BNF, bu you might use BNF to describe what a sentence is That description would probably enumerate the characters acceptable in a sentence
  • BNF grammar and Operator Associativity - Stack Overflow
    The BNF grammar given seems consistent with the parse tree, and consistent with the claim that "and" is supposed to be left-associative If you want to produce "a and b and c" using this grammar, starting with "Clause", you start this way: Clause; Clause and Phrase
  • Precedence of operators in BNF grammar - Stack Overflow
    Swapping + and * in the grammar will clearly swap the precedence, but making them right-associative is a separate step, so that's easy
  • BNF vs EBNF vs ABNF: which to choose? - Stack Overflow
    BNF A ::= B C B ::= a | b | c EBNF A ::= (a | b | c) C This is true for many syntax issues that are allowed in an EBNF or ABNF grammar, thanks to syntactic sugar but not with a normal BNF ABNF extends EBNF , allowing you to do more complicated things, like specifying how many occurrence of a symbol can be found together (i e 4*DIGIT )
  • bnf - Tool for generating railroad diagram used on json. org - Stack . . .
    There is an Online Railroad Diagram Generator It creates SVG syntax diagrams, also known as railroad diagrams, from context-free grammars specified in EBNF
  • What goes in between { and } when writing BNF? - Stack Overflow
    The IETF uses RFC-5234 and its dialect of BNF does not use '{}' at all In a Yacc grammar, though, the braces enclose the actions to be performed when the rule is matched (reduced in the jargon) So, the '{$$ = $1;}' action means 'assign the value matched by 'term' to the result of reducing 'exp ::= term' (using another variant of BNF)
  • bnf - describing something, should i use Backus-Naur Form . . . - Stack . . .
    Augmented BNF Wirth syntax notation Van Wijngaarden grammar Personally I would stick with BNF EBNF due to the prevalence of information and tools which use it in some form Tools like bison or yacc can help with the generation of a parser from such a grammar and make it quite trivial to produce an interpreter





中文字典-英文字典  2005-2009