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-rw-r--r--docs/examples/parsers1.scala122
1 files changed, 0 insertions, 122 deletions
diff --git a/docs/examples/parsers1.scala b/docs/examples/parsers1.scala
deleted file mode 100644
index e4aeea3613..0000000000
--- a/docs/examples/parsers1.scala
+++ /dev/null
@@ -1,122 +0,0 @@
-package examples
-
-object parsers1 {
-
- abstract class Parsers {
-
- type inputType;
-
- abstract class Parser {
-
- type Result = Option[inputType]
-
- def apply(in: inputType): Result
-
- /*** p &&& q applies first p, and if that succeeds, then q
- */
- def &&& (q: => Parser) = new Parser {
- def apply(in: inputType): 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 ||| (q: => Parser) = new Parser {
- def apply(in: inputType): Result = Parser.this.apply(in) match {
- case None => q(in)
- case s => s
- }
- }
- }
-
- val empty = new Parser {
- def apply(in: inputType): Result = Some(in)
- }
-
- val fail = new Parser {
- def apply(in: inputType): 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*
- }
-
- trait ListParsers extends Parsers {
- def chr(p: char => boolean): Parser
- def chr(c: char): Parser = chr((d: char) => d == c)
-
- def letter : Parser = chr((c: char) => Character.isLetter(c))
- def digit : Parser = chr((c: char) => Character.isDigit(c))
-
- 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
- }
-
- trait ExprParsers extends Parsers {
- def chr(p: char => boolean): Parser
- def chr(c: char): Parser = chr((d: char) => d == c)
-
- def digit : Parser = chr((c: char) => Character.isDigit(c))
- 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 inputType = 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]) {
- Console.println(
- if (args.length == 1) {
- val ps = new ParseString(args(0)) with ListParsers
- ps.expr(ps.input) match {
- case Some(n) =>
- "parsed: " + args(0).substring(0, n)
- case None =>
- "nothing parsed"
- }
- }
- else
- "usage: java examples.TestList <expr-string>"
- )
- }
- }
-
- object TestExpr {
- def main(args: Array[String]) {
- Console.println(
- if (args.length == 1) {
- val ps = new ParseString(args(0)) with ExprParsers
- ps.expr(ps.input) match {
- case Some(n) =>
- "parsed: " + args(0).substring(0, n)
- case None =>
- "nothing parsed"
- }
- }
- else
- "usage: java examples.TestExpr <expr-string>"
- )
- }
- }
-
- def main(args: Array[String]) {
- TestList.main(Array("(a,b,(1,2))"))
- TestExpr.main(Array("2+3+(4+1)"))
- }
-
-}