FABulous: Add auto set for FAB_ROOT env var and add main()

Automatically sets the fabulousRoot path if no FAB_ROOT env var is specified.

Add Python interpreter path in file header.

Add main() function.

Signed-off-by: Jonas K. <[email protected]>

FABulous/FABulous.py

@@ -1,3 +1,5 @@
+#!/usr/bin/env python
+
 # Copyright 2021 University of Manchester
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -45,17 +47,29 @@
 
 MAX_BITBYTES = 16384
 
-fabulousRoot = os.getenv("FAB_ROOT")
-if fabulousRoot is None:
-    print("FAB_ROOT environment variable not set!")
-    print("Use 'export FAB_ROOT=<path to FABulous root>'")
-    sys.exit(-1)
-
 logger = logging.getLogger(__name__)
 logging.basicConfig(
     format="[%(levelname)s]-%(asctime)s - %(message)s", level=logging.INFO
 )
 
+metaDataDir = ".FABulous"
+
+fabulousRoot = os.getenv('FAB_ROOT')
+if fabulousRoot is None:
+    fabulousRoot = os.path.dirname(os.path.realpath(__file__))
+    logger.warning("FAB_ROOT environment variable not set!")
+    logger.warning(f"Using {fabulousRoot} as FAB_ROOT")
+else:
+    if not os.path.exists(fabulousRoot):
+        logger.error(
+            f"FAB_ROOT environment variable set to {fabulousRoot} but the directory does not exist")
+        sys.exit()
+    else:
+        if os.path.exists(f"{fabulousRoot}/FABulous"):
+            fabulousRoot = f"{fabulousRoot}/FABulous"
+
+    logger.info(f"FAB_ROOT set to {fabulousRoot}")
+
 
 # Create a FABulous Verilog project that contains all the required files
 def create_project(project_dir, type: Literal["verilog", "vhdl"] = "verilog"):
@@ -161,8 +175,8 @@ class FABulousShell(cmd.Cmd):
 
 Type help or ? to list commands
 To see documentation for a command type:
-    help <command> 
-or 
+    help <command>
+or
     ?<command>
 
 To execute a shell command type:
@@ -230,8 +244,7 @@ def inter(*args, **varargs):
                 if fun.startswith("do_"):
                     name = fun.strip("do_")
                     tcl.createcommand(
-                        name, wrap_with_except_handling(getattr(self, fun))
-                    )
+                        name, wrap_with_except_handling(getattr(self, fun)))
 
         # os.chdir(args.project_dir)
         tcl.eval(script)
@@ -1179,7 +1192,7 @@ def complete_tcl(self, text, *ignored):
         return self._complete_path(text)
 
 
-if __name__ == "__main__":
+def main():
     if sys.version_info < (3, 9, 0):
         print("Need Python 3.9 or above to run FABulous")
         exit(-1)
@@ -1232,7 +1245,6 @@ def complete_tcl(self, text, *ignored):
     args = parser.parse_args()
 
     args.top = args.project_dir.split("/")[-1]
-    metaDataDir = ".FABulous"
 
     if args.createProject:
         create_project(args.project_dir, args.writer)
@@ -1267,3 +1279,7 @@ def complete_tcl(self, text, *ignored):
                     fabShell.cmdloop()
         else:
             fabShell.cmdloop()
+
+
+if __name__ == "__main__":
+    main()