mbligh | e8819cd | 2008-02-15 16:48:40 +0000 | [diff] [blame] | 1 | """\ |
| 2 | Generic enumeration support. |
| 3 | """ |
| 4 | |
| 5 | __author__ = 'showard@google.com (Steve Howard)' |
| 6 | |
| 7 | class Enum(object): |
jadmanski | 0afbb63 | 2008-06-06 21:10:57 +0000 | [diff] [blame] | 8 | """\ |
| 9 | Utility class to implement Enum-like functionality. |
mbligh | e8819cd | 2008-02-15 16:48:40 +0000 | [diff] [blame] | 10 | |
jadmanski | 0afbb63 | 2008-06-06 21:10:57 +0000 | [diff] [blame] | 11 | >>> e = Enum('String one', 'String two') |
| 12 | >>> e.STRING_ONE |
| 13 | 0 |
| 14 | >>> e.STRING_TWO |
| 15 | 1 |
| 16 | >>> e.choices() |
| 17 | [(0, 'String one'), (1, 'String two')] |
| 18 | >>> e.get_value('String one') |
| 19 | 0 |
| 20 | >>> e.get_string(0) |
| 21 | 'String one' |
mbligh | e8819cd | 2008-02-15 16:48:40 +0000 | [diff] [blame] | 22 | |
jadmanski | 0afbb63 | 2008-06-06 21:10:57 +0000 | [diff] [blame] | 23 | >>> e = Enum('Hello', 'Goodbye', string_values=True) |
| 24 | >>> e.HELLO, e.GOODBYE |
| 25 | ('Hello', 'Goodbye') |
mbligh | e8819cd | 2008-02-15 16:48:40 +0000 | [diff] [blame] | 26 | |
jadmanski | 0afbb63 | 2008-06-06 21:10:57 +0000 | [diff] [blame] | 27 | >>> e = Enum('One', 'Two', start_value=1) |
| 28 | >>> e.ONE |
| 29 | 1 |
| 30 | >>> e.TWO |
| 31 | 2 |
| 32 | """ |
| 33 | def __init__(self, *names, **kwargs): |
| 34 | self.string_values = kwargs.get('string_values') |
| 35 | start_value = kwargs.get('start_value', 0) |
Alex Miller | ef446dd | 2013-09-04 15:25:31 -0700 | [diff] [blame] | 36 | step = kwargs.get('step', 1) |
jadmanski | 0afbb63 | 2008-06-06 21:10:57 +0000 | [diff] [blame] | 37 | self.names = names |
| 38 | self.values = [] |
| 39 | for i, name in enumerate(names): |
| 40 | if self.string_values: |
| 41 | value = name |
| 42 | else: |
Alex Miller | ef446dd | 2013-09-04 15:25:31 -0700 | [diff] [blame] | 43 | value = i * step + start_value |
jadmanski | 0afbb63 | 2008-06-06 21:10:57 +0000 | [diff] [blame] | 44 | self.values.append(value) |
| 45 | setattr(self, self.get_attr_name(name), value) |
mbligh | e8819cd | 2008-02-15 16:48:40 +0000 | [diff] [blame] | 46 | |
| 47 | |
jadmanski | 0afbb63 | 2008-06-06 21:10:57 +0000 | [diff] [blame] | 48 | @staticmethod |
| 49 | def get_attr_name(string): |
| 50 | return string.upper().replace(' ', '_') |
mbligh | e8819cd | 2008-02-15 16:48:40 +0000 | [diff] [blame] | 51 | |
| 52 | |
jadmanski | 0afbb63 | 2008-06-06 21:10:57 +0000 | [diff] [blame] | 53 | def choices(self): |
| 54 | 'Return choice list suitable for Django model choices.' |
| 55 | return zip(self.values, self.names) |
mbligh | e8819cd | 2008-02-15 16:48:40 +0000 | [diff] [blame] | 56 | |
| 57 | |
jadmanski | 0afbb63 | 2008-06-06 21:10:57 +0000 | [diff] [blame] | 58 | def get_value(self, name): |
| 59 | """\ |
| 60 | Convert a string name to it's corresponding value. If a value |
| 61 | is passed in, it is returned. |
| 62 | """ |
Aviv Keshet | 7c72f9c | 2013-05-21 15:53:41 -0700 | [diff] [blame] | 63 | if isinstance(name, (int, long)) and not self.string_values: |
jadmanski | 0afbb63 | 2008-06-06 21:10:57 +0000 | [diff] [blame] | 64 | # name is already a value |
| 65 | return name |
| 66 | return getattr(self, self.get_attr_name(name)) |
mbligh | e8819cd | 2008-02-15 16:48:40 +0000 | [diff] [blame] | 67 | |
| 68 | |
jadmanski | 0afbb63 | 2008-06-06 21:10:57 +0000 | [diff] [blame] | 69 | def get_string(self, value): |
| 70 | ' Given a value, get the string name for it.' |
| 71 | if value not in self.values: |
| 72 | raise ValueError('Value %s not in this enum' % value) |
| 73 | index = self.values.index(value) |
| 74 | return self.names[index] |