add listing.py to list out data

listing.py

@@ -0,0 +1,44 @@
+#!/usr/bin/python
+
+import record
+import sys
+
+red = '\033[31m'
+blue = '\033[34m'
+green = '\033[32m'
+reset = '\033[0m'
+
+def printRecord(rec, level):
+    try: filename = rec.data['file']
+    except KeyError: filename = None
+
+    # TODO: if multi-inherit, specify correct inherit_order
+    try: index = rec.data['inherit_order']
+    except KeyError: index = None
+
+    print("  " * level +
+        f"[{red}{index}{reset}] {green}{rec.name}{reset}, {blue}{filename}{reset}")
+
+    for i in rec.children:
+        printRecord(rec.children[i], level + 1)
+
+def main():
+    try:
+        rec = record.RecordCollection(sys.argv[1])
+    except IndexError:
+        print(f"[{red}error{reset}] you didn't specify the file!")
+        return
+    except FileNotFoundError:
+        print(f"[{red}error{reset}] the file doesn't exist!")
+        return
+    except FileParsingError:
+        print(f"[{red}error{reset}] error parsing file!")
+        return
+
+    entries = rec.findEntrypoints()
+
+    for i in entries:
+        printRecord(i, 0)
+
+if __name__ == '__main__':
+    main()