From 8bce47e9d1824fce3d93f05a13bafd4fda71e7ea Mon Sep 17 00:00:00 2001
From: Simon Chu <cchu2@andrew.cmu.edu>
Date: Tue, 9 Jul 2019 22:46:38 -0400
Subject: [PATCH] Resolved issue #326, supported command line arguments, added
 example Wyvern program that demonstrate the usage of command line argument

---
 examples/commandLineArguments.wyv             | 19 ++++++++++++
 tools/src/wyvern/stdlib/Globals.java          |  1 +
 .../stdlib/support/CommandLineUtils.java      | 30 +++++++++++++++++++
 tools/src/wyvern/tools/Interpreter.java       | 21 +++++++++----
 4 files changed, 66 insertions(+), 5 deletions(-)
 create mode 100644 examples/commandLineArguments.wyv
 create mode 100644 tools/src/wyvern/stdlib/support/CommandLineUtils.java

diff --git a/examples/commandLineArguments.wyv b/examples/commandLineArguments.wyv
new file mode 100644
index 000000000..c37c95fed
--- /dev/null
+++ b/examples/commandLineArguments.wyv
@@ -0,0 +1,19 @@
+// program to print all the command line arguments given by the user
+// delimited by comma
+
+require stdout
+require java
+import java:wyvern.stdlib.support.CommandLineUtils.utils
+
+val cmdLineArgs = utils.getArgs() // store the arguments in a dynamic array.
+
+def printCmdLineArgs(index: Int): Unit
+  if (index != utils.getLength() - 1)
+      stdout.print(cmdLineArgs.get(index))
+      stdout.print(", ")
+      printCmdLineArgs(index + 1)
+    else
+      stdout.print(cmdLineArgs.get(utils.getLength() - 1))
+      stdout.println()
+
+printCmdLineArgs(0)
diff --git a/tools/src/wyvern/stdlib/Globals.java b/tools/src/wyvern/stdlib/Globals.java
index 54410c5bb..b3e67ce2e 100644
--- a/tools/src/wyvern/stdlib/Globals.java
+++ b/tools/src/wyvern/stdlib/Globals.java
@@ -65,6 +65,7 @@ private Globals() { }
         javaWhiteList.add("wyvern.stdlib.support.Sys.utils");
         javaWhiteList.add("wyvern.stdlib.support.HashMapWrapper.hashmapwrapper");
         javaWhiteList.add("wyvern.stdlib.support.ArrayWrapper.arr");
+        javaWhiteList.add("wyvern.stdlib.support.CommandLineUtils.utils");
     }
 
     static {
diff --git a/tools/src/wyvern/stdlib/support/CommandLineUtils.java b/tools/src/wyvern/stdlib/support/CommandLineUtils.java
new file mode 100644
index 000000000..6e714bc18
--- /dev/null
+++ b/tools/src/wyvern/stdlib/support/CommandLineUtils.java
@@ -0,0 +1,30 @@
+package wyvern.stdlib.support;
+
+public class CommandLineUtils {
+    private static String[] arguments; // array of command line arguments.
+    private static DynArrayList argumentsArrayList; // array list of command line arguments.
+    public static final CommandLineUtils utils = new CommandLineUtils();
+
+    private CommandLineUtils() {
+    }
+
+    public CommandLineUtils(String[] arguments) {
+        this.arguments = arguments;
+        this.convertToDynArrayList();
+    }
+
+    public DynArrayList getArgs() {
+        return argumentsArrayList;
+    }
+
+    public int getLength() {
+        return arguments.length;
+    }
+
+    private void convertToDynArrayList() {
+        argumentsArrayList = new DynArrayList();
+        for (String str : arguments) {
+            argumentsArrayList.add(str);
+        }
+    }
+}
\ No newline at end of file
diff --git a/tools/src/wyvern/tools/Interpreter.java b/tools/src/wyvern/tools/Interpreter.java
index 88ab30869..5cafe1c9a 100644
--- a/tools/src/wyvern/tools/Interpreter.java
+++ b/tools/src/wyvern/tools/Interpreter.java
@@ -6,6 +6,7 @@
 import java.nio.file.Paths;
 
 import wyvern.stdlib.Globals;
+import wyvern.stdlib.support.CommandLineUtils;
 import wyvern.target.corewyvernIL.ASTNode;
 import wyvern.target.corewyvernIL.astvisitor.PlatformSpecializationVisitor;
 import wyvern.target.corewyvernIL.astvisitor.TailCallVisitor;
@@ -18,16 +19,26 @@
 public final class Interpreter {
     private Interpreter() { }
     /**
-     * The interpreter only supports 1 argument, which is the path to the Wyvern
-     * file. If more arguments are supplied, it will exit with an error. Then,
+     * The interpreter supports multiple arguments, the first argument (0th index)
+     * supplied will always be the path to the Wyvern file. The command line arguments
+     * will be stored in the dynamic array defined in stdlib/support/CommandLineArgumentsUtils.java
+     * and can be accessed by Wyvern program via the following import statement:
+     *
+     * require java
+     * import java:wyvern.stdlib.support.CommandLineUtils.utils
+     *
      * the file is read in to memory in it's entirety, before being executed in
      * an empty context. The resulting value is printed to the screen.
      */
     public static void main(String[] args) {
-        // check if 1 argument is supplied.
-        if (args.length != 1) {
-            System.err.println("usage: wyvern <filename>");
+        // check if at least one argument is supplied.
+        if (args.length < 1) {
+            // prompt usage message if the number of arguments is less than one.
+            System.err.println("usage: wyvern <filename> <arguments>");
             System.exit(1);
+        } else {
+            // create CommandLineUtils object to store the command line arguments.
+            CommandLineUtils commandLineUtilsObject = new CommandLineUtils(args);
         }
         String filename = args[0];
         Path filepath = Paths.get(filename);