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diff --git a/vendor/github.com/tdewolff/parse/v2/js/README.md b/vendor/github.com/tdewolff/parse/v2/js/README.md new file mode 100644 index 0000000..e1d4007 --- /dev/null +++ b/vendor/github.com/tdewolff/parse/v2/js/README.md @@ -0,0 +1,80 @@ +# JS [](https://pkg.go.dev/github.com/tdewolff/minify/v2/parse/js?tab=doc) + +This package is a JS lexer (ECMAScript 2020) written in [Go][1]. It follows the specification at [ECMAScript 2020 Language Specification](https://tc39.es/ecma262/). The lexer takes an io.Reader and converts it into tokens until the EOF. + +## Installation +Run the following command + + go get -u github.com/tdewolff/parse/v2/js + +or add the following import and run project with `go get` + + import "github.com/tdewolff/parse/v2/js" + +## Lexer +### Usage +The following initializes a new Lexer with io.Reader `r`: +``` go +l := js.NewLexer(parse.NewInput(r)) +``` + +To tokenize until EOF an error, use: +``` go +for { + tt, text := l.Next() + switch tt { + case js.ErrorToken: + // error or EOF set in l.Err() + return + // ... + } +} +``` + +### Regular Expressions +The ECMAScript specification for `PunctuatorToken` (of which the `/` and `/=` symbols) and `RegExpToken` depend on a parser state to differentiate between the two. The lexer will always parse the first token as `/` or `/=` operator, upon which the parser can rescan that token to scan a regular expression using `RegExp()`. + +### Examples +``` go +package main + +import ( + "os" + + "github.com/tdewolff/parse/v2/js" +) + +// Tokenize JS from stdin. +func main() { + l := js.NewLexer(parse.NewInput(os.Stdin)) + for { + tt, text := l.Next() + switch tt { + case js.ErrorToken: + if l.Err() != io.EOF { + fmt.Println("Error on line", l.Line(), ":", l.Err()) + } + return + case js.IdentifierToken: + fmt.Println("Identifier", string(text)) + case js.NumericToken: + fmt.Println("Numeric", string(text)) + // ... + } + } +} +``` + +## Parser +### Usage +The following parses a file and returns an abstract syntax tree (AST). +``` go +ast, err := js.NewParser(parse.NewInputString("if (state == 5) { console.log('In state five'); }")) +``` + +See [ast.go](https://github.com/tdewolff/parse/blob/master/js/ast.go) for all available data structures that can represent the abstact syntax tree. + +## License +Released under the [MIT license](https://github.com/tdewolff/parse/blob/master/LICENSE.md). + +[1]: http://golang.org/ "Go Language" |