import java.io.File

fun grepFile(file: File, pattern: Regex) {
    file.forEachLine {
        if (pattern.matches(it)) {
            println(it)
        }
    }
}

fun grepFile(path: String, pattern: String) {
    grepFile(File(path), Regex(pattern))
}

fun grepFiles(root: File, suffix: String, pattern: Regex) {
    if (root.isFile && root.name.endsWith(suffix)) {
        grepFile(root, pattern)
        return
    }
    if (root.isDirectory) {
        for (f in root.listFiles()) {
            grepFiles(f, suffix, pattern)
        }
    }
}

fun grepFiles(rootPath: String, suffix: String, pattern: String) {
    grepFiles(File(rootPath), suffix, Regex(pattern))
}

fun main(args: Array<String>) {
    grepFiles("src", ".kt", "\\{");
}