# 5.1.2 The Lexical and RegExp Grammars

ECMAScript的*词法文法（lexical）*在规范[条款11](https://github.com/js-geek/ecmascript-language-specification-cn/tree/8255e51ad8526c3a1dcf79b6c70215a896ad1301/manuscript/11_ecmascript_language_lexical_grammar/README.md)中给出。该文法使用遵守[条款10.1](https://github.com/js-geek/ecmascript-language-specification-cn/tree/8255e51ad8526c3a1dcf79b6c70215a896ad1301/manuscript/10_scmascript_language_source_code/10_1_source_text.md)定义的*SourceCharacter*的Unicode编码点（code point）作为终结符号。该文法定义了一组产生式，起始于目标符号（goal symbol）*InputElementDiv*，*InputElementTemplateTail*，或*InputElementRegExp*，或*InputElementRegExpOrTemplateTail*，它们描述了代码点序列如何被转换成输入元素序列。 and

除空白符和注释外的输入元素，组成ECMAScript的句法（syntactic grammar）的终结符，被称为ECMAScrpit的记号（tokens）。这些记号是ECMAScript语言的保留字，标示符，字面量和标点符号。此外，断行符（line terminator）虽然不被认为是记号，但也是输入元素流（stream）的一部分，会引导自动分号插入（[automatic semicolon insertion](https://github.com/js-geek/ecmascript-language-specification-cn/tree/8255e51ad8526c3a1dcf79b6c70215a896ad1301/manuscript/11_ecmascript_language_lexical_grammar/11_9_automatic_semicolon_insertion.md)（[11.9](https://github.com/js-geek/ecmascript-language-specification-cn/tree/8255e51ad8526c3a1dcf79b6c70215a896ad1301/manuscript/11_ecmascript_language_lexical_grammar/11_9_automatic_semicolon_insertion.md)））的过程。简单的空白和单行注释会被删除，不会显示在句法的输入元素流中。一个*MultiLineComment*（即/\*...\*/形式的注释，无论它是否跨越了多行），如果没有包含断行符，同样会被删除，但如果包含了一个或多个断行符，则会被一个单独的断行符替换，成为句法的输入元素流的一部分。

ECMAScript的*RegExp文法*在[21.2.1](https://github.com/js-geek/ecmascript-language-specification-cn/tree/8255e51ad8526c3a1dcf79b6c70215a896ad1301/manuscript/21_text_processing/21_2_regexp_objects.md)中定义。该文法有*SourceCharacter*定义的代码点作为自己的终结符号。它定义了一组产生式，起始于目标符号*Pattern*，它描述了代码点序列如何被转换成正则表达式模式。

两个冒号“::”作为分隔符来区分词法和正则表达式文法的产生式。词法和正则表达式文法共享某些产生式。


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