Add options and options parser

- Add --version option
- Add --help option
- Add --no-cache option

ETA.py

@@ -8,11 +8,47 @@ from scipy.signal import convolve as sp_convolve
 from scipy.signal import find_peaks
 from scipy.ndimage import rotate
 
-cache = True
+cache , filename = True , None
 if len( sys.argv ) < 2:
-    raise Exception( 'this command must have a filename of an ETA fits as an argument' )
+    raise Exception( 'ETA.py: type \'ETA.py -h\' for more information' )
 
-data = utils.load( sys.argv[1] )
+for arg in sys.argv[ 1 : ]:
+    if arg[0] == '-':
+        if len( arg ) < 2:
+            raise Exception( 'ETA.py: unknown argument, type \'ETA.py -h\' for more information' )
+        if arg[1] != '-':
+            if arg == '-h':
+                arg = '--help'
+            elif arg == '-v':
+                arg = '--version'
+            elif arg == '-n':
+                arg == '--no-cachge'
+            else:
+                raise Exception( 'ETA.py: unknown argument "' + arg + '", type \'ETA.py -h\' for more information' )
+        if arg[1] == '-': # not elif because arg can change after last if
+            if arg == '--help':
+                print( 'ETA.py [options...] filename\
+                      \n    -h --help     show this help and quit\
+                      \n    -v --version  show version number and quit\
+                      \n    -n --no-cache do not use cache and rewrite it\
+                      \n\
+                      \nParse a naroo ETA fits' )
+                exit()
+            elif arg == '--version':
+                print( '0.1' )
+                exit()
+            elif arg == '--no-cache':
+                cache = False
+            else:
+                raise Exception( 'ETA.py: unknown argument "' + arg + '", type \'ETA.py -h\' for more information' )
+        else:
+            raise Exception( 'ETA.py: this exception should never be raised' )
+    else:
+        filename = arg
+if filename == None:
+    raise Exception( 'ETA.py: filename should be given' )
+
+data = utils.load( filename )
 
 cache_file = pathlib.Path( 'asset/points_' + sys.argv[1].split( '/' )[-1][:-5] + '.pag' )