Add support for decimal places in Rounder

src/api/config.py

@@ -5,7 +5,7 @@
 
 def config_init(
     sigfigs: int = 2,
-    decimal_places: int = 2,
+    decimal_places: int = -1,  # -1: "per default use sigfigs instead"
     print_always: bool = False,
     min_exponent_for_non_scientific_notation: int = -2,
     max_exponent_for_non_scientific_notation: int = 3,

src/api/res.py

@@ -100,7 +100,7 @@ def res(
     result = _Result(
         name_res, value_res, unit_res, uncertainties_res, sigfigs_res, decimal_places_res
     )
-    _Rounder.round_result(result, configuration.sigfigs)
+    _Rounder.round_result(result, configuration.sigfigs, configuration.decimal_places)
     _res_cache.add(name, result)
 
     return PrintableResult(result)

src/application/rounder.py

@@ -1,4 +1,4 @@
-from typing import List
+from typing import List, Union
 
 from domain.result import _Result
 from domain.uncertainty import _Uncertainty
@@ -8,37 +8,50 @@
 class _Rounder:
 
     @classmethod
-    def round_result(cls, result: _Result, sigfigs_default: int) -> None:
+    def round_result(cls, result: _Result, sigfigs_default: int, decimal_places: int) -> None:
         """
         In-place rounds all numerical fields of a result to the correct
         number of significant figures.
 
-        Rounding hierarchy for uncertainties:
+        # Rounding hierarchy:
 
-        1. Is uncertainty exact? Do not round!
-        2. Round uncertainty according to the hierarchy below!
+        1. Is uncertainty exact? Do not round.
+        2. Round uncertainty according to the hierarchy below.
 
-        Rounding hierarchy:
 
-        1. Is value exact? Do not round! Round uncertainty according to value!
-        2. Is number of sigfigs given? Round value according to number of sigfigs! Round
-        uncertainties according to value.
-        3. Is number of decimal places given? Round value according to number of decimal places!
-        Round uncertainties according to value.
-        4. Is at least one uncertainty given? Round each uncertainty according to standard rules!
-        Round value according to uncertainty with lowest min exponent!
-        5. Round value to 2 sigfigs.
+        # Rounding hierarchy for inexact uncertainty:
+
+        1. Is result value exact?
+           Round uncertainty according to result value.
+
+        2. Is default for decimal places given (not -1) (see method param)?
+           Round value according to number of decimal places.
+           Round uncertainties according to value.
+
+        3. Is number of sigfigs of result given?
+           Round value according to number of sigfigs.
+           Round uncertainties according to value.
+
+        4. Is number of decimal places of result given?
+           Round value according to number of decimal places.
+           Round uncertainties according to value.
+
+        5. Is at least one uncertainty given?
+           Round each uncertainty according to standard rules.
+           Round value according to uncertainty with lowest min exponent.
+
+        6. Round value to the default for the sigfigs (see method param).
 
         TODO: Warning message if user specifies exact value and sigfigs etc.
         """
-        cls._round_result(result, sigfigs_default)
+        cls._round_result(result, sigfigs_default, decimal_places)
 
         short = result.get_short_result()
         if short:
-            cls._round_result(short, sigfigs_default)
+            cls._round_result(short, sigfigs_default, decimal_places)
 
     @classmethod
-    def _round_result(cls, result: _Result, sigfigs_default: int) -> None:
+    def _round_result(cls, result: _Result, sigfigs_default: int, decimal_places: int) -> None:
         """See the docstring of the public `round_result` for details."""
 
         value = result.value
@@ -49,16 +62,22 @@ def _round_result(cls, result: _Result, sigfigs_default: int) -> None:
             cls._uncertainties_set_min_exponents(uncertainties, value.get_min_exponent())
 
         # Rounding hierarchy 2:
+        elif decimal_places != -1:
+            min_exponent = -decimal_places
+            value.set_min_exponent(min_exponent)
+            cls._uncertainties_set_min_exponents(uncertainties, min_exponent)
+
+        # Rounding hierarchy 3:
         elif result.sigfigs is not None:
             value.set_sigfigs(result.sigfigs)
             cls._uncertainties_set_min_exponents(uncertainties, value.get_min_exponent())
 
-        # Rounding hierarchy 3:
+        # Rounding hierarchy 4:
         elif result.decimal_places is not None:
             value.set_min_exponent(-result.decimal_places)
             cls._uncertainties_set_min_exponents(uncertainties, value.get_min_exponent())
 
-        # Rounding hierarchy 4:
+        # Rounding hierarchy 5:
         elif len(uncertainties) > 0:
             for u in uncertainties:
                 if u.uncertainty.is_exact():
@@ -88,4 +107,3 @@ def _uncertainties_set_min_exponents(
         for u in uncertainties:
             if not u.uncertainty.is_exact():
                 u.uncertainty.set_min_exponent(min_exponent)
-        return

tests/playground.py

@@ -15,8 +15,9 @@
 print()
 
 
-wiz.config_init(decimal_places=3, print_always=True)
-
+wiz.config_init(print_always=True, sigfigs=10)
+wiz.config(sigfigs=2)
+# wiz.config(decimal_places=2)
 
 #############################
 # EXAMPLES
@@ -27,7 +28,6 @@
 wiz.res("a1", 1.0, r"\mm").print()
 # a: 1.0 \mm
 
-wiz.config(sigfigs=2)
 
 wiz.res("1 b", 1.0, 0.01, r"\per\mm\cubed").print()
 # b: (1.0 ± 0.01) \mm
@@ -40,18 +40,14 @@
 ).print()
 # d: (1.0 ± 0.01 systematic ± 0.02 stat) \mm
 
-# wiz.standard_sigfigs(4)
-
 wiz.res("e", "1.0", r"\mm").print()
 # e: 1.0 \mm
 
-wiz.config(decimal_places=4)
-
-# wiz.standard_sigfigs(3)
-
 wiz.res("f", "1.0e1", 25e-1).print()
 # f: 1.0
 
+wiz.res("a", 42.0).print()
+
 # wiz.res("g", 1.0, sys=0.01, stat=0.02, unit=r"\mm").print()
 # g: (1.0 ± 0.01 sys ± 0.02 stat) \mm
 # TODO: Why does this not work?