44 lines
1.5 KiB
Python
44 lines
1.5 KiB
Python
# This file is part of Tryton. The COPYRIGHT file at the top level of
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# this repository contains the full copyright notices and license terms.
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from tokenize import tokenize, untokenize, NUMBER, NAME, OP, STRING
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from io import BytesIO
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# code snippet taken from http://docs.python.org/library/tokenize.html
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def decistmt(s):
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"""Substitute Decimals for floats in a string of statements.
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>>> from decimal import Decimal
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>>> s = 'print(+21.3e-5*-.1234/81.7)'
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>>> decistmt(s)
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"print (+Decimal ('21.3e-5')*-Decimal ('.1234')/Decimal ('81.7'))"
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The format of the exponent is inherited from the platform C library.
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Known cases are "e-007" (Windows) and "e-07" (not Windows). Since
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we're only showing 12 digits, and the 13th isn't close to 5, the
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rest of the output should be platform-independent.
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>>> exec(s) #doctest: +ELLIPSIS
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-3.217160342717258e-0...7
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Output from calculations with Decimal should be identical across all
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platforms.
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>>> exec(decistmt(s))
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-3.217160342717258261933904529E-7
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"""
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result = []
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g = tokenize(BytesIO(s.encode('utf-8')).readline) # tokenize the string
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for toknum, tokval, _, _, _ in g:
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if toknum == NUMBER and '.' in tokval: # replace NUMBER tokens
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result.extend([
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(NAME, 'Decimal'),
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(OP, '('),
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(STRING, repr(tokval)),
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(OP, ')')
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])
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else:
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result.append((toknum, tokval))
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return untokenize(result).decode('utf-8')
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