RustPython · youknowone · Jul 25, 2025 · Jul 25, 2025
diff --git a/Lib/_pydecimal.py b/Lib/_pydecimal.py
diff --git a/Lib/decimal.py b/Lib/decimal.py
@@ -1,11 +1,109 @@
+"""Decimal fixed-point and floating-point arithmetic.
+
+This is an implementation of decimal floating-point arithmetic based on
+the General Decimal Arithmetic Specification:
+
+    http://speleotrove.com/decimal/decarith.html
+
+and IEEE standard 854-1987:
+
+    http://en.wikipedia.org/wiki/IEEE_854-1987
+
+Decimal floating point has finite precision with arbitrarily large bounds.
+
+The purpose of this module is to support arithmetic using familiar
+"schoolhouse" rules and to avoid some of the tricky representation
+issues associated with binary floating point.  The package is especially
+useful for financial applications or for contexts where users have
+expectations that are at odds with binary floating point (for instance,
+in binary floating point, 1.00 % 0.1 gives 0.09999999999999995 instead
+of 0.0; Decimal('1.00') % Decimal('0.1') returns the expected
+Decimal('0.00')).
+
+Here are some examples of using the decimal module:
+
+>>> from decimal import *
+>>> setcontext(ExtendedContext)
+>>> Decimal(0)
+Decimal('0')
+>>> Decimal('1')
+Decimal('1')
+>>> Decimal('-.0123')
+Decimal('-0.0123')
+>>> Decimal(123456)
+Decimal('123456')
+>>> Decimal('123.45e12345678')
+Decimal('1.2345E+12345680')
+>>> Decimal('1.33') + Decimal('1.27')
+Decimal('2.60')
+>>> Decimal('12.34') + Decimal('3.87') - Decimal('18.41')
+Decimal('-2.20')
+>>> dig = Decimal(1)
+>>> print(dig / Decimal(3))
+0.333333333
+>>> getcontext().prec = 18
+>>> print(dig / Decimal(3))
+0.333333333333333333
+>>> print(dig.sqrt())
+1
+>>> print(Decimal(3).sqrt())
+1.73205080756887729
+>>> print(Decimal(3) ** 123)
+4.85192780976896427E+58
+>>> inf = Decimal(1) / Decimal(0)
+>>> print(inf)
+Infinity
+>>> neginf = Decimal(-1) / Decimal(0)
+>>> print(neginf)
+-Infinity
+>>> print(neginf + inf)
+NaN
+>>> print(neginf * inf)
+-Infinity
+>>> print(dig / 0)
+Infinity
+>>> getcontext().traps[DivisionByZero] = 1
+>>> print(dig / 0)
+Traceback (most recent call last):
+  ...
+  ...
+  ...
+decimal.DivisionByZero: x / 0
+>>> c = Context()
+>>> c.traps[InvalidOperation] = 0
+>>> print(c.flags[InvalidOperation])
+0
+>>> c.divide(Decimal(0), Decimal(0))
+Decimal('NaN')
+>>> c.traps[InvalidOperation] = 1
+>>> print(c.flags[InvalidOperation])
+1
+>>> c.flags[InvalidOperation] = 0
+>>> print(c.flags[InvalidOperation])
+0
+>>> print(c.divide(Decimal(0), Decimal(0)))
+Traceback (most recent call last):
+  ...
+  ...
+  ...
+decimal.InvalidOperation: 0 / 0
+>>> print(c.flags[InvalidOperation])
+1
+>>> c.flags[InvalidOperation] = 0
+>>> c.traps[InvalidOperation] = 0
+>>> print(c.divide(Decimal(0), Decimal(0)))
+NaN
+>>> print(c.flags[InvalidOperation])
+1
+>>>
+"""
 
 try:
     from _decimal import *
-    from _decimal import __doc__
     from _decimal import __version__
     from _decimal import __libmpdec_version__
 except ImportError:
-    from _pydecimal import *
-    from _pydecimal import __doc__
-    from _pydecimal import __version__
-    from _pydecimal import __libmpdec_version__
+    import _pydecimal
+    import sys
+    _pydecimal.__doc__ = __doc__
+    sys.modules[__name__] = _pydecimal
diff --git a/Lib/test/decimaltestdata/abs.decTest b/Lib/test/decimaltestdata/abs.decTest
@@ -20,7 +20,7 @@
 version: 2.59
 
 -- This set of tests primarily tests the existence of the operator.
--- Additon, subtraction, rounding, and more overflows are tested
+-- Addition, subtraction, rounding, and more overflows are tested
 -- elsewhere.
 
 precision:   9

diff --git a/Lib/test/decimaltestdata/ddFMA.decTest b/Lib/test/decimaltestdata/ddFMA.decTest
@@ -1663,7 +1663,7 @@ ddfma375087 fma  1  12345678 1E-33                   -> 12345678.00000001 Inexac
 ddfma375088 fma  1  12345678 1E-34                   -> 12345678.00000001 Inexact Rounded
 ddfma375089 fma  1  12345678 1E-35                   -> 12345678.00000001 Inexact Rounded
 
--- desctructive subtraction (from remainder tests)
+-- destructive subtraction (from remainder tests)
 
 -- +++ some of these will be off-by-one remainder vs remainderNear
 

diff --git a/Lib/test/decimaltestdata/ddQuantize.decTest b/Lib/test/decimaltestdata/ddQuantize.decTest
@@ -462,7 +462,7 @@ ddqua520 quantize   1.234    1e359 -> 0E+359 Inexact Rounded
 ddqua521 quantize 123.456    1e359 -> 0E+359 Inexact Rounded
 ddqua522 quantize   1.234    1e359 -> 0E+359 Inexact Rounded
 ddqua523 quantize 123.456    1e359 -> 0E+359 Inexact Rounded
--- next four are "won't fit" overfl
+-- next four are "won't fit" overflow
 ddqua526 quantize   1.234   1e-299 -> NaN Invalid_operation
 ddqua527 quantize 123.456   1e-299 -> NaN Invalid_operation
 ddqua528 quantize   1.234   1e-299 -> NaN Invalid_operation

diff --git a/Lib/test/decimaltestdata/ddRemainder.decTest b/Lib/test/decimaltestdata/ddRemainder.decTest
@@ -422,7 +422,7 @@ ddrem757 remainder  1    sNaN   ->  NaN  Invalid_operation
 ddrem758 remainder  1000 sNaN   ->  NaN  Invalid_operation
 ddrem759 remainder  Inf -sNaN   -> -NaN  Invalid_operation
 
--- propaging NaNs
+-- propagating NaNs
 ddrem760 remainder  NaN1   NaN7   ->  NaN1
 ddrem761 remainder sNaN2   NaN8   ->  NaN2 Invalid_operation
 ddrem762 remainder  NaN3  sNaN9   ->  NaN9 Invalid_operation

diff --git a/Lib/test/decimaltestdata/ddRemainderNear.decTest b/Lib/test/decimaltestdata/ddRemainderNear.decTest
@@ -450,7 +450,7 @@ ddrmn757 remaindernear  1    sNaN   ->  NaN  Invalid_operation
 ddrmn758 remaindernear  1000 sNaN   ->  NaN  Invalid_operation
 ddrmn759 remaindernear  Inf -sNaN   -> -NaN  Invalid_operation
 
--- propaging NaNs
+-- propagating NaNs
 ddrmn760 remaindernear  NaN1   NaN7   ->  NaN1
 ddrmn761 remaindernear sNaN2   NaN8   ->  NaN2 Invalid_operation
 ddrmn762 remaindernear  NaN3  sNaN9   ->  NaN9 Invalid_operation

diff --git a/Lib/test/decimaltestdata/dqRemainder.decTest b/Lib/test/decimaltestdata/dqRemainder.decTest
@@ -418,7 +418,7 @@ dqrem757 remainder  1    sNaN   ->  NaN  Invalid_operation
 dqrem758 remainder  1000 sNaN   ->  NaN  Invalid_operation
 dqrem759 remainder  Inf -sNaN   -> -NaN  Invalid_operation
 
--- propaging NaNs
+-- propagating NaNs
 dqrem760 remainder  NaN1   NaN7   ->  NaN1
 dqrem761 remainder sNaN2   NaN8   ->  NaN2 Invalid_operation
 dqrem762 remainder  NaN3  sNaN9   ->  NaN9 Invalid_operation

diff --git a/Lib/test/decimaltestdata/dqRemainderNear.decTest b/Lib/test/decimaltestdata/dqRemainderNear.decTest
@@ -450,7 +450,7 @@ dqrmn757 remaindernear  1    sNaN   ->  NaN  Invalid_operation
 dqrmn758 remaindernear  1000 sNaN   ->  NaN  Invalid_operation
 dqrmn759 remaindernear  Inf -sNaN   -> -NaN  Invalid_operation
 
--- propaging NaNs
+-- propagating NaNs
 dqrmn760 remaindernear  NaN1   NaN7   ->  NaN1
 dqrmn761 remaindernear sNaN2   NaN8   ->  NaN2 Invalid_operation
 dqrmn762 remaindernear  NaN3  sNaN9   ->  NaN9 Invalid_operation

diff --git a/Lib/test/decimaltestdata/exp.decTest b/Lib/test/decimaltestdata/exp.decTest
@@ -28,7 +28,7 @@ rounding:    half_even
 maxExponent: 384
 minexponent: -383
 
--- basics (examples in specificiation, etc.)
+-- basics (examples in specification, etc.)
 expx001 exp  -Infinity     -> 0
 expx002 exp  -10           -> 0.0000453999298 Inexact Rounded
 expx003 exp  -1            -> 0.367879441 Inexact Rounded

diff --git a/Lib/test/decimaltestdata/extra.decTest b/Lib/test/decimaltestdata/extra.decTest
@@ -156,7 +156,7 @@ extr1302 fma -Inf 0E-456 sNaN148 -> NaN Invalid_operation
 
 -- max/min/max_mag/min_mag bug in 2.5.2/2.6/3.0: max(NaN, finite) gave
 -- incorrect answers when the finite number required rounding; similarly
--- for the other thre functions
+-- for the other three functions
 maxexponent: 999
 minexponent: -999
 precision: 6

diff --git a/Lib/test/decimaltestdata/remainder.decTest b/Lib/test/decimaltestdata/remainder.decTest
@@ -435,7 +435,7 @@ remx757 remainder  1    sNaN   ->  NaN  Invalid_operation
 remx758 remainder  1000 sNaN   ->  NaN  Invalid_operation
 remx759 remainder  Inf -sNaN   -> -NaN  Invalid_operation
 
--- propaging NaNs
+-- propagating NaNs
 remx760 remainder  NaN1   NaN7   ->  NaN1
 remx761 remainder sNaN2   NaN8   ->  NaN2 Invalid_operation
 remx762 remainder  NaN3  sNaN9   ->  NaN9 Invalid_operation

diff --git a/Lib/test/decimaltestdata/remainderNear.decTest b/Lib/test/decimaltestdata/remainderNear.decTest
@@ -498,7 +498,7 @@ rmnx758 remaindernear  1000 sNaN   ->  NaN  Invalid_operation
 rmnx759 remaindernear  Inf  sNaN   ->  NaN  Invalid_operation
 rmnx760 remaindernear  NaN  sNaN   ->  NaN  Invalid_operation
 
--- propaging NaNs
+-- propagating NaNs
 rmnx761 remaindernear  NaN1   NaN7   ->  NaN1
 rmnx762 remaindernear sNaN2   NaN8   ->  NaN2 Invalid_operation
 rmnx763 remaindernear  NaN3 -sNaN9   -> -NaN9 Invalid_operation