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Diffstat (limited to 'docs/examples/parsing/ArithmeticParser.scala')
-rw-r--r-- | docs/examples/parsing/ArithmeticParser.scala | 57 |
1 files changed, 0 insertions, 57 deletions
diff --git a/docs/examples/parsing/ArithmeticParser.scala b/docs/examples/parsing/ArithmeticParser.scala deleted file mode 100644 index 99cf7a5578..0000000000 --- a/docs/examples/parsing/ArithmeticParser.scala +++ /dev/null @@ -1,57 +0,0 @@ -/* __ *\ -** ________ ___ / / ___ Scala API ** -** / __/ __// _ | / / / _ | (c) 2006-2011, LAMP/EPFL ** -** __\ \/ /__/ __ |/ /__/ __ | ** -** /____/\___/_/ |_/____/_/ | | ** -** |/ ** -\* */ - -package examples.parsing - -import scala.util.parsing.combinator.lexical.StdLexical -import scala.util.parsing.combinator.syntactical.StdTokenParsers - -/** Parse and evaluate a numeric expression as a sequence of terms, separated by + or - - * a term is a sequence of factors, separated by * or / - * a factor is a parenthesized expression or a number - * - * @author Adriaan Moors - */ -object arithmeticParser extends StdTokenParsers { - type Tokens = StdLexical ; val lexical = new StdLexical - lexical.delimiters ++= List("(", ")", "+", "-", "*", "/") - - lazy val expr = term*("+" ^^^ {(x: int, y: int) => x + y} | "-" ^^^ {(x: int, y: int) => x - y}) - lazy val term = factor*("*" ^^^ {(x: int, y: int) => x * y} | "/" ^^^ {(x: int, y: int) => x / y}) - lazy val factor: Parser[int] = "(" ~> expr <~ ")" | numericLit ^^ (_.toInt) - - def main(args: Array[String]) { - println( - if (args.length == 1) { - expr(new lexical.Scanner(args(0))) - } - else - "usage: scala examples.parsing.arithmeticParser <expr-string>" - ) - } -} - - -object arithmeticParserDesugared extends StdTokenParsers { - type Tokens = StdLexical ; val lexical = new StdLexical - lexical.delimiters ++= List("(", ")", "+", "-", "*", "/") - - lazy val expr = chainl1(term, (keyword("+").^^^{(x: int, y: int) => x + y}).|(keyword("-").^^^{(x: int, y: int) => x - y})) - lazy val term = chainl1(factor, (keyword("*").^^^{(x: int, y: int) => x * y}).|(keyword("/").^^^{(x: int, y: int) => x / y})) - lazy val factor: Parser[int] = keyword("(").~>(expr.<~(keyword(")"))).|(numericLit.^^(x => x.toInt)) - - def main(args: Array[String]) { - println( - if (args.length == 1) { - expr(new lexical.Scanner(args(0))) - } - else - "usage: scala examples.parsing.arithmeticParser <expr-string>" - ) - } -} |