Remove dependency on combinators from CommandLinerParser.

tools.cmd.CommandLineParser uses a small hand-rolled parser

TODO: replace partest's usage of scala.tools.nsc.util.CommandLine
by scala.tools.cmd.CommandLine

1 files changed, 72 insertions, 0 deletions

diff --git a/src/compiler/scala/tools/cmd/CommandLineParser.scala b/src/compiler/scala/tools/cmd/CommandLineParser.scala
new file mode 100644
index 0000000000..ef55178594
--- /dev/null
+++ b/src/compiler/scala/tools/cmd/CommandLineParser.scala
@@ -0,0 +1,72 @@
+/* NEST (New Scala Test)
+ * Copyright 2007-2013 LAMP/EPFL
+ * @author Paul Phillips
+ */
+
+package scala.tools
+package cmd
+
+import scala.annotation.tailrec
+
+/** A simple (overly so) command line parser.
+ *  !!! This needs a thorough test suite to make sure quoting is
+ *  done correctly and portably.
+ */
+object CommandLineParser {
+  // splits a string into a quoted prefix and the rest of the string,
+  // taking escaping into account (using \)
+  // `"abc"def` will match as `DoubleQuoted(abc, def)`
+  private class QuotedExtractor(quote: Char) {
+    def unapply(in: String): Option[(String, String)] = {
+      val del = quote.toString
+      if (in startsWith del) {
+        var escaped = false
+        val (quoted, next) = (in substring 1) span {
+          case `quote` if !escaped => false
+          case '\\'    if !escaped => escaped = true; true
+          case _                   => escaped = false; true
+        }
+        // the only way to get out of the above loop is with an empty next or !escaped
+        // require(next.isEmpty || !escaped)
+        if (next startsWith del) Some((quoted, next substring 1))
+        else None
+      } else None
+    }
+  }
+  private object DoubleQuoted extends QuotedExtractor('"')
+  private object SingleQuoted extends QuotedExtractor('\'')
+  private val Word = """(\S+)(.*)""".r
+
+  // parse `in` for an argument, return it and the remainder of the input (or an error message)
+  // (argument may be in single/double quotes, taking escaping into account, quotes are stripped)
+  private def argument(in: String): Either[String, (String, String)] = in match {
+    case DoubleQuoted(arg, rest) => Right(arg, rest)
+    case SingleQuoted(arg, rest) => Right(arg, rest)
+    case Word(arg, rest)         => Right(arg, rest)
+    case _                       => Left("Illegal argument: "+ in)
+  }
+
+  // parse a list of whitespace-separated arguments (ignoring whitespace in quoted arguments)
+  @tailrec private def commandLine(in: String, accum: List[String] = Nil): Either[String, (List[String], String)] = {
+    val trimmed = in.trim
+    if (trimmed.isEmpty) Right(accum.reverse, "")
+    else argument(trimmed) match {
+      case Right((arg, next)) =>
+        (next span Character.isWhitespace) match {
+          case("", rest) if rest.nonEmpty => Left("Arguments should be separated by whitespace.") // TODO: can this happen?
+          case(ws, rest)                  => commandLine(rest, arg :: accum)
+        }
+      case Left(msg) => Left(msg)
+    }
+  }
+
+  class ParseException(msg: String) extends RuntimeException(msg)
+
+  def tokenize(line: String): List[String] = tokenize(line, x => throw new ParseException(x))
+  def tokenize(line: String, errorFn: String => Unit): List[String] = {
+    commandLine(line) match {
+      case Right((args, _)) => args
+      case Left(msg)        => errorFn(msg) ; Nil
+    }
+  }
+}