/* NSC -- new Scala compiler
* Copyright 2005-2006 LAMP/EPFL
* @author Martin Odersky
*/
// $Id$
package scala.tools.nsc
import java.io.{BufferedReader, FileReader, File}
import scala.tools.nsc.util._
import scala.tools.nsc.io._
/** A main routine to support putting Scala code into scripts.
*
* An shell script example on Unix would look like this:
*
* #!/bin/sh
* exec scalascript "$0" "$@"
* !#
* Console.println("Hello, world!")
* argv.toList foreach Console.println
*
* A batch file example on Windows XP would look like this:
*
* ::#!
* @echo off
* call scalascript %0 %*
* goto :eof
* ::!#
* Console.println("Hello, world!")
* argv.toList foreach Console.println
*
* TODO: It would be better if error output went to stderr instead
* of stdout....
*/
object MainScript {
/** Read the entire contents of a file as a String. */
private def contentsOfFile(filename: String): String = {
val strbuf = new StringBuffer
val reader = new FileReader(filename)
val cbuf = new Array[Char](1024)
while(true) {
val n = reader.read(cbuf)
if(n <= 0)
return strbuf.toString
strbuf.append(cbuf, 0, n)
}
throw new Error("impossible")
}
/** Find the length of the header in the specified file, if
* there is one. The header part starts with "#!" or "::#!"
* and ends with a line that begins with "!#" ar "::!#".
*/
def headerLength(filename: String): Int = {
import java.util.regex._
val fileContents = contentsOfFile(filename)
if(!(fileContents.startsWith("#!") || fileContents.startsWith("::#!")))
return 0
val matcher =
(Pattern.compile("^(::)?!#.*(\\r|\\n|\\r\\n)", Pattern.MULTILINE)
.matcher(fileContents))
if(! matcher.find)
throw new Error("script file does not close its header with !# or ::!#")
return matcher.end
}
/** Print a usage message and then exit. */
def usageExit: Nothing = {
Console.println(
"scalascript [ compiler arguments... - ] scriptfile " +
"[ script arguments... ]")
Console.println
Console.println(
"Note that if you do specify compiler arguments, you \n" +
"must put an explicit hyphen (\"-\") at the end of them.")
System.exit(1).asInstanceOf[Nothing]
}
/** Parse an argument list into three portions:
*
* Arguments to the compiler
* The filename of the script to run
* Arguments to pass to the script
*/
def parseArgs(args: List[String])
:Tuple3[List[String], String, List[String]] =
{
if (args.length == 0)
usageExit
if (args(0).startsWith("-")) {
// the line includes compiler arguments
val hyphenIndex = args.indexOf("-")
if (hyphenIndex < 0)
usageExit
if (hyphenIndex == (args.length - 1))
usageExit
Tuple3(
args.subseq(0, hyphenIndex).toList,
args(hyphenIndex + 1),
args.subseq(hyphenIndex + 2, args.length - hyphenIndex - 2).toList)
} else {
Tuple3(
Nil,
args(0),
args.subseq(1, args.length-1).toList)
}
}
def wrappedScript(filename: String): SourceFile = {
val preamble =
new SourceFile("<script preamble>",
("package scala.scripting\n" +
"object Main {\n" +
" def main(argv: Array[String]): Unit = {\n" +
" val args = argv;\n").toCharArray)
val middle =
new SourceFileFragment(
new SourceFile(new PlainFile(new File(filename))),
headerLength(filename),
new File(filename).length.asInstanceOf[Int])
val end = new SourceFile("<script trailer>", "\n} }\n".toCharArray)
new CompoundSourceFile(preamble, middle, end)
}
def runScript(
settings: Settings,
scriptFile: String,
scriptArgs: List[String]): Unit =
{
val interpreter = new Interpreter(settings)
try {
interpreter.beQuiet
if(!interpreter.compileSources(List(wrappedScript(scriptFile))))
return () // compilation error
interpreter.bind("argv", "Array[String]", scriptArgs.toArray)
interpreter.interpret("scala.scripting.Main.main(argv)")
} finally {
interpreter.close
}
}
def main(args: Array[String]): Unit = {
val parsedArgs = parseArgs(args.toList)
val compilerArgs = parsedArgs._1
val scriptFile = parsedArgs._2
val scriptArgs = parsedArgs._3
val command =
new CompilerCommand(
compilerArgs,
Console.println,
false)
if (!command.ok || command.settings.help.value) {
// either the command line is wrong, or the user
// explicitly requested a help listing
if (!command.ok)
Console.println
usageExit
}
runScript(command.settings, scriptFile, scriptArgs)
}
}
