https://github.com/wangchunsen/parser
A pure function parser library for general purpose
https://github.com/wangchunsen/parser
parser scala
Last synced: 8 months ago
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A pure function parser library for general purpose
- Host: GitHub
- URL: https://github.com/wangchunsen/parser
- Owner: wangchunsen
- Created: 2019-02-22T06:10:16.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2020-05-08T08:39:48.000Z (about 6 years ago)
- Last Synced: 2025-01-10T00:14:50.934Z (over 1 year ago)
- Topics: parser, scala
- Language: Scala
- Size: 35.2 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# parser
A pure function parser library for general purpose
Here is a example of parsing html using this library:
```scala
type AttrValue = (String, Option[String])
val voidElements = Array("area", "base", "br", "col", "embed",
"hr", "img", "input", "link", "meta", "param", "source", "track", "wbr")
val textElement = Array("script", "style", "textarea", "title")
val spaceChars = Array(' ', '\t', '\n', '\r', '\f')
def isWhiteSpace(char: Char) = spaceChars.contains(char)
def tagName: Parser[String] =
p(charsWhileIn("a-z0-9A-Z_").cap)
def attributeName: Parser[String] = p {
val illegalChars = spaceChars ++ Array('=', '/', '>', '"', '\'')
charsWhile(char => !illegalChars.contains(char)).min(1).cap
}
def maybeSpace: PUnit = charsWhileIn(spaceChars)
def mustSpace: PUnit = charsWhileIn(spaceChars) min 1
def attribute: Parser[AttrValue] =
mustSpace ~ attributeName ~ (maybeSpace ~> "=" ~> maybeSpace ~> attrValue).opt
def attributes: Parser[Seq[AttrValue]] = attribute.rep
def attrValue: Parser[String] = p {
def quotedValue(quote: Char): Parser[String] = p(charsWhile(c => c != quote).cap <~ quote)
def noQuote: Parser[String] = p {
val illegalChars = spaceChars ++ Array('\'', '"', '>', '<', '=', '`')
charsWhile(c => !illegalChars.contains(c)).cap
}
("\"" | "'").cap.opt flatMap { quote =>
quote
.map { q => quotedValue(q.charAt(0)) }
.getOrElse(noQuote)
}
}
def text: Parser[Text] = charsWhile(c => c != '<').cap map Text
def comment: Parser[Comment] =
p(allBetween("") map Comment)
def node: Parser[Node] = comment | element | text
def closeType: Parser[Boolean] =
maybeSpace ~> ("/>" ~> pass(true) | (">" ~> pass(false))).!!
def allBetween(start: String, end: String): Parser[String] = {
val content: Parser[String] = matchAll.cap ~: charsUntil(end)
start ~> content <~ end
}
def scriptElement: Parser[Node] =
p(allBetween("", "") map Text)
def closeTag: Parser[String] = p("" ~> tagName.cap <~ maybeSpace <~ ">")
def element: Parser[Element] =
"<" ~> tagName ~ attributes ~ closeType flatMap (t => {
val (tagName, attrs, closed) = t
def element(children: Seq[Node] = Seq.empty): Element = Element(tagName = tagName, attributes = ListMap(attrs: _*))
if (closed || voidElements(tagName)) pass(element())
else {
val childrenNodes = node.rep
childrenNodes <~ s"$tagName>" map {nodes =>
element(children = nodes)
}
}
})
```