Feature: NeoLang command line program

NeoLang/src/main/java/io/neolang/command/Main.kt

@@ -0,0 +1,40 @@
+package io.neolang.command
+
+import io.neolang.parser.NeoLangParser
+import java.io.FileInputStream
+
+/**
+ * @author kiva
+ */
+class Main {
+    companion object {
+        @JvmStatic
+        fun main(args: Array<String>) {
+            if (args.isEmpty()) {
+                println("Usage: NeoLang <program.nl>")
+                return
+            }
+
+            val parser = NeoLangParser()
+            args.forEach {
+                val programCode = readFully(it)
+                parser.setInputSource(programCode)
+                val ast = parser.parse()
+                println("Compile `$it' -> $ast")
+            }
+            return
+        }
+
+        private fun readFully(file: String): String {
+            try {
+                FileInputStream(file).use {
+                    val bytes = ByteArray(it.available())
+                    it.read(bytes)
+                    return String(bytes)
+                }
+            } catch (e: Exception) {
+                return ""
+            }
+        }
+    }
+}