1 |
1468
|
aaronmk
|
# Quantities with units
|
2 |
|
|
# This file's encoding must be UTF-8Y with BOM so Python will auto-detect UTF-8
|
3 |
|
|
|
4 |
|
|
import re
|
5 |
|
|
|
6 |
|
|
import format
|
7 |
|
|
import strings
|
8 |
|
|
import util
|
9 |
|
|
|
10 |
|
|
class MissingUnitsException(Exception):
|
11 |
1476
|
aaronmk
|
def __init__(self, quantity):
|
12 |
|
|
Exception.__init__(self, 'Quantity has no units: '+quantity)
|
13 |
1468
|
aaronmk
|
|
14 |
|
|
def std_units(units):
|
15 |
|
|
if units == None: return units
|
16 |
|
|
else: return strings.remove_suffix('.', units) # for abbr ending in '.'
|
17 |
|
|
# TODO: deal with '"° and abbrs
|
18 |
|
|
|
19 |
1471
|
aaronmk
|
class Quantity:
|
20 |
|
|
def __init__(self, value='', units=None):
|
21 |
|
|
self.value = value
|
22 |
|
|
self.units = std_units(util.none_if(units, u''))
|
23 |
|
|
|
24 |
|
|
def quantity2str(quantity):
|
25 |
|
|
str_ = quantity.value
|
26 |
|
|
if quantity.units != None: str_ += ' '+quantity.units
|
27 |
|
|
return str_
|
28 |
|
|
|
29 |
|
|
Quantity.__str__ = quantity2str
|
30 |
1566
|
aaronmk
|
Quantity.__repr__ = quantity2str
|
31 |
1471
|
aaronmk
|
|
32 |
|
|
def str2quantity(str_):
|
33 |
|
|
value = str_
|
34 |
1468
|
aaronmk
|
units = None
|
35 |
1471
|
aaronmk
|
if not str_.isdigit(): # optimization to avoid regexp for simple cases
|
36 |
1566
|
aaronmk
|
match = re.match(ur'(?i)^\s*(.*?\d\.?)\s*([a-z%\'"°][\w.*/^-]*?)?\s*$',
|
37 |
1471
|
aaronmk
|
str_)
|
38 |
|
|
if match: value, units = match.groups() # has units
|
39 |
|
|
return Quantity(value, units)
|
40 |
1468
|
aaronmk
|
|
41 |
1471
|
aaronmk
|
def set_default_units(quantity, units):
|
42 |
|
|
if quantity.units == None: quantity.units = units
|
43 |
|
|
|
44 |
1566
|
aaronmk
|
conversions = {
|
45 |
|
|
('%', None): 1./100
|
46 |
|
|
}
|
47 |
|
|
|
48 |
1471
|
aaronmk
|
def convert(quantity, units):
|
49 |
|
|
units = std_units(units)
|
50 |
1565
|
aaronmk
|
if quantity.units == units: return quantity # units already correct
|
51 |
1566
|
aaronmk
|
try: conversion = conversions[(quantity.units, units)]
|
52 |
|
|
except KeyError:
|
53 |
|
|
if units == None: return Quantity(quantity.value, units) # remove units
|
54 |
|
|
elif quantity.units == None: raise MissingUnitsException(quantity)
|
55 |
|
|
# can't convert quantity with unknown units
|
56 |
|
|
else: raise NotImplementedError('Unit conversion not implemented yet')
|
57 |
|
|
else:
|
58 |
|
|
return Quantity(str(format.str2float(quantity.value)*conversion), units)
|