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+/* __ *\
+** ________ ___ / / ___ Scala benchmark suite **
+** / __/ __// _ | / / / _ | (c) 2003-2004, LAMP/EPFL **
+** __\ \/ /__/ __ |/ /__/ __ | **
+** /____/\___/_/ |_/____/_/ | | **
+** |/ **
+** $Id$
+\* */
+
+package benchmarks;
+
+/** The parsers example from the scala distribution. */
+abstract class Parsers {
+
+ type intype;
+
+ abstract class Parser {
+
+ type Result = Option[intype];
+
+ def apply(in: intype): Result;
+
+ /*** p &&& q applies first p, and if that succeeds, then q
+ */
+ def &&& (def q: Parser) = new Parser {
+ def apply(in: intype): Result = Parser.this.apply(in) match {
+ case None => None
+ case Some(in1) => q(in1)
+ }
+ }
+
+ /*** p ||| q applies first p, and, if that fails, then q.
+ */
+ def ||| (def q: Parser) = new Parser {
+ def apply(in: intype): Result = Parser.this.apply(in) match {
+ case None => q(in)
+ case s => s
+ }
+ }
+ }
+
+ val empty = new Parser {
+ def apply(in: intype): Result = Some(in)
+ }
+
+ val fail = new Parser {
+ def apply(in: intype): Result = None
+ }
+
+ def opt(p: Parser): Parser = p ||| empty; // p? = (p | <empty>)
+ def rep(p: Parser): Parser = opt(rep1(p)); // p* = [p+]
+ def rep1(p: Parser): Parser = p &&& rep(p); // p+ = p p*
+}
+
+abstract class ListParsers extends Parsers {
+
+ def chr(p: char => boolean): Parser;
+
+ def chr(c: char): Parser = chr(d: char => d == c);
+
+ def letter : Parser = chr(Character.isLetter);
+ def digit : Parser = chr(Character.isDigit);
+
+ def ident : Parser = letter &&& rep(letter ||| digit);
+ def number : Parser = digit &&& rep(digit);
+ def list : Parser = chr('(') &&& listElems &&& chr(')');
+ def listElems : Parser = expr &&& (chr(',') &&& listElems ||| empty);
+ def expr : Parser = ident ||| number ||| list;
+}
+
+abstract class ExprParsers extends Parsers {
+ def chr(p: char => boolean): Parser;
+ def chr(c: char): Parser = chr(d: char => d == c);
+
+ def digit : Parser = chr(Character.isDigit);
+ def number : Parser = digit &&& rep(digit);
+ def summand : Parser = number ||| chr('(') &&& expr &&& chr(')');
+ def expr : Parser = summand &&& rep(chr('+') &&& summand)
+}
+
+class ParseString(s: String) extends Parsers {
+ type intype = int;
+ val input = 0;
+ def chr(p: char => boolean) = new Parser {
+ def apply(in: int): Parser#Result =
+ if (in < s.length() && p(s charAt in)) Some(in + 1);
+ else None;
+ }
+}
+
+object TestList {
+
+ def main(args: Array[String]): unit =
+ if (args.length == 1) {
+ val ps = new ListParsers with ParseString(args(0));
+ ps.expr(ps.input) match {
+ case Some(n) =>
+ System.out.println("parsed: " + args(0).substring(0, n));
+ case None =>
+ System.out.println("nothing parsed");
+ }
+ } else System.out.println("usage: java examples.TestList <expr-string>");
+}
+
+object TestExpr {
+
+ def main(args: Array[String]): unit =
+ if (args.length == 1) {
+ val ps = new ExprParsers with ParseString(args(0));
+ ps.expr(ps.input) match {
+ case Some(n) =>
+ System.out.println("parsed: " + args(0).substring(0, n));
+ case None =>
+ System.out.println("nothing parsed");
+ }
+ } else System.out.println("usage: java examples.TestExpr <expr-string>");
+}
+
+object parsers1 with scala.testing.Benchmark {
+ def run: Unit = {
+ TestList.main(Array("(a,b,(1,2))"));
+ TestExpr.main(Array("2+3+(4+1)"))
+ }
+}