I have created a bit of path-finding code in response to [this](http://codegolf.stackexchange.com/questions/64529/i-like-to-move-it-move-it/65189#65189) code golf question. Since this is one of my first large bits of code in Groovy that I have written, I would like to see how I could improve it.

<!-- language: lang-groovy -->

    def invalid() {
        println "Invalid map."
        System.exit(1)
    }
    
    def map =
            """01001E
    010110
    000P00
    1100J1
    S00111""".split('\n')
    
    //map = [""]// TODO remove this, this is type checking only
    //map.remove(0)
    //reader = System.in.newReader()
    //line = reader.readLine()
    //while (line != '') {
    //    map << line
    //    line = reader.readLine()
    //}
    
    def size = map[0].size()
    map.each { if (it.size() != size) invalid() }
    
    def startLocation = [0, 0]
    def endLocation = [0, 0]
    map.eachWithIndex { it, idx ->
        def startIdx = it.indexOf('S')
        def endIdx = it.indexOf('E')
        
        if (startIdx != -1) {
            startLocation[0] = startIdx; startLocation[1] = idx
        }
        if (endIdx != -1) {
            endLocation[0] = endIdx; endLocation[1] = idx
        }
    }
    
    def validPath = []
    
    testMove = { x, y, visited ->// visited is an array of x y pairs that we have already visited in this tree
        if (visited.contains([x, y]) || y >= map.size() || x >= map[0].size() || x < 0 || y < 0)
            return;
    
        def chr = map[y][x]
        def newPath = visited + [[x, y]]
    
        if (chr == 'E') validPath = newPath
        if ('J0S'.contains(chr) && !validPath) {
            testMove(x - 1, y, newPath)
            testMove(x + 1, y, newPath)
            testMove(x, y + 1, newPath)
            testMove(x, y - 1, newPath)
        }
    }
    testMove(startLocation[0], startLocation[1], [])
    if (!validPath) invalid()
    
    println validPath
    
    def orintation = 0
    def path = ''
    validPath.inject { first, second ->
        def chr = map[second[1]][second[0]]
        def sub = [first[0] - second[0], first[1] - second[1]]
        def newOrin = [[0, 1]: 0, [1, 0]: 1, [0, -1]: 2, [-1, 0]: 3][sub]
        path += ((((orintation - newOrin) == 0) ? '' : (newOrin > 0 ? 'R' : 'L')) + (chr == 'J' ? 'M' : '') + 'F')
        orintation = newOrin
        second
    }
    println "path: $path"