diff options
Diffstat (limited to 'Lib/decimal.py')
| -rw-r--r-- | Lib/decimal.py | 55 |
1 files changed, 23 insertions, 32 deletions
diff --git a/Lib/decimal.py b/Lib/decimal.py index 3eee436..61f8c33 100644 --- a/Lib/decimal.py +++ b/Lib/decimal.py @@ -18,15 +18,10 @@ the General Decimal Arithmetic Specification: www2.hursley.ibm.com/decimal/decarith.html -IEEE standard 854-1987: +and IEEE standard 854-1987: www.cs.berkeley.edu/~ejr/projects/754/private/drafts/854-1987/dir.html -and ANSI standard X3.274-1996: - - www.rexxla.org/Standards/ansi.html - - Decimal floating point has finite precision with arbitrarily large bounds. The purpose of the module is to support arithmetic using familiar @@ -128,19 +123,13 @@ __all__ = [ 'Inexact', 'InvalidContext', 'Rounded', 'Subnormal', 'Overflow', 'Underflow', - # Module parameters - 'DEFAULT_MAX_EXPONENT', 'DEFAULT_MIN_EXPONENT', - # Constants for use in setting up contexts 'ROUND_DOWN', 'ROUND_HALF_UP', 'ROUND_HALF_EVEN', 'ROUND_CEILING', 'ROUND_FLOOR', 'ROUND_UP', 'ROUND_HALF_DOWN', 'Signals', # <-- Used for building trap/flag dictionaries # Functions for manipulating contexts - 'setcontext', 'getcontext', - - # Functions for working with decimals - 'isinfinity', 'isnan', + 'setcontext', 'getcontext' ] import threading @@ -153,17 +142,17 @@ DEFAULT_MAX_EXPONENT = 999999999 DEFAULT_MIN_EXPONENT = -999999999 #Rounding -ROUND_DOWN = 'down' -ROUND_HALF_UP = 'half_up' -ROUND_HALF_EVEN = 'half_even' -ROUND_CEILING = 'ceiling' -ROUND_FLOOR = 'floor' -ROUND_UP = 'up' -ROUND_HALF_DOWN = 'half_down' +ROUND_DOWN = 'ROUND_DOWN' +ROUND_HALF_UP = 'ROUND_HALF_UP' +ROUND_HALF_EVEN = 'ROUND_HALF_EVEN' +ROUND_CEILING = 'ROUND_CEILING' +ROUND_FLOOR = 'ROUND_FLOOR' +ROUND_UP = 'ROUND_UP' +ROUND_HALF_DOWN = 'ROUND_HALF_DOWN' #Rounding decision (not part of the public API) -NEVER_ROUND = 'never' # Round in division (non-divmod), sqrt ONLY -ALWAYS_ROUND = 'always' # Every operation rounds at end. +NEVER_ROUND = 'NEVER_ROUND' # Round in division (non-divmod), sqrt ONLY +ALWAYS_ROUND = 'ALWAYS_ROUND' # Every operation rounds at end. #Errors @@ -468,17 +457,17 @@ class Decimal(object): # String? # REs insist on real strings, so we can too. if isinstance(value, basestring): - if isinfinity(value): + if _isinfinity(value): self._exp = 'F' self._int = (0,) - sign = isinfinity(value) + sign = _isinfinity(value) if sign == 1: self._sign = 0 else: self._sign = 1 return - if isnan(value): - sig, sign, diag = isnan(value) + if _isnan(value): + sig, sign, diag = _isnan(value) if len(diag) > context.prec: #Diagnostic info too long self._sign, self._int, self._exp = \ context._raise_error(ConversionSyntax) @@ -2127,8 +2116,8 @@ class Context(object): flags - When an exception is caused, flags[exception] is incremented. (Whether or not the trap_enabler is set) Should be reset by user of Decimal instance. - Emin - Minimum exponent (defaults to -999999999) - Emax - Maximum exponent (defaults to 999999999) + Emin - Minimum exponent + Emax - Maximum exponent capitals - If 1, 1*10^1 is printed as 1E+1. If 0, printed as 1e1 (Defaults to 1) @@ -2140,7 +2129,7 @@ class Context(object): def __init__(self, prec=None, rounding=None, trap_enablers=None, flags=None, _rounding_decision=None, - Emin=DEFAULT_MIN_EXPONENT, Emax=DEFAULT_MAX_EXPONENT, + Emin=None, Emax=None, capitals=1, _clamp=0, _ignored_flags=[]): if flags is None: @@ -2927,15 +2916,15 @@ _infinity_map = { '-infinity' : -1 } -def isinfinity(num): +def _isinfinity(num): """Determines whether a string or float is infinity. - +1 for positive infinity; 0 for finite ; +1 for positive infinity + +1 for negative infinity; 0 for finite ; +1 for positive infinity """ num = str(num).lower() return _infinity_map.get(num, 0) -def isnan(num): +def _isnan(num): """Determines whether a string or float is NaN (1, sign, diagnostic info as string) => NaN @@ -2978,6 +2967,8 @@ DefaultContext = Context( trap_enablers=dict.fromkeys(Signals, 0), flags=None, _rounding_decision=ALWAYS_ROUND, + Emax=DEFAULT_MAX_EXPONENT, + Emin=DEFAULT_MIN_EXPONENT ) # Pre-made alternate contexts offered by the specification |