Add a command line parsing procedure

source/CommandLineInterface.def

@@ -0,0 +1,15 @@
+DEFINITION MODULE CommandLineInterface;
+
+FROM Common IMPORT ShortString;
+
+TYPE
+  CommandLine = RECORD
+    input: ShortString;
+    lex: BOOLEAN;
+    parse: BOOLEAN
+  END;
+  PCommandLine = POINTER TO CommandLine;
+
+PROCEDURE parse_command_line(): PCommandLine;
+
+END CommandLineInterface.