feat(altnumber): Add NoLimit, Autocalculate and Autosize objects

This commit addresses [this issue here](#30).

honeybee_schema/altnumber.py

@@ -0,0 +1,17 @@
+"""Objects used as alternatives to numerical properties."""
+from pydantic import BaseModel, constr
+
+
+class NoLimit(BaseModel):
+
+    type: constr(regex='^NoLimit$') = 'NoLimit'
+
+
+class Autocalculate(BaseModel):
+
+    type: constr(regex='^Autocalculate$') = 'Autocalculate'
+
+
+class Autosize(BaseModel):
+
+    type: constr(regex='^Autosize$') = 'Autosize'

honeybee_schema/bc.py

@@ -2,6 +2,8 @@
 from pydantic import BaseModel, Field, constr
 from typing import List, Union
 
+from .altnumber import Autocalculate
+
 
 class Outdoors(BaseModel):
 
@@ -17,12 +19,12 @@ class Outdoors(BaseModel):
         description='A boolean noting whether the boundary is exposed to wind.'
     )
 
-    view_factor: Union[str, float] = Field(
-        'autocalculate',
+    view_factor: Union[Autocalculate, float] = Field(
+        Autocalculate(),
         ge=0,
         le=1,
         description='A number for the view factor to the ground. This can also be '
-            'the word "autocalculate" to have the view factor automatically calculated.'
+            'an Autocalculate object to have the view factor automatically calculated.'
     )
 
 class Surface(BaseModel):

honeybee_schema/energy/hvac.py

@@ -4,6 +4,7 @@
 from enum import Enum
 
 from ._base import NamedEnergyBaseModel
+from ..altnumber import NoLimit, Autosize
 
 
 class EconomizerType(str, Enum):
@@ -62,37 +63,24 @@ class IdealAirSystemAbridged(NamedEnergyBaseModel):
         description='A number for the minimum cooling supply air temperature [C].'
     )
 
-    heating_limit: Union[float, str] = Field(
-        'autosize',
+    heating_limit: Union[float, Autosize, NoLimit] = Field(
+        Autosize(),
         ge=0,
         description='A number for the maximum heating capacity in Watts. This '
-            'can also be the text "autosize" to indicate that the capacity should '
+            'can also be an Autosize object to indicate that the capacity should '
             'be determined during the EnergyPlus sizing calculation. This can also '
-            'be the text "NoLimit" to indicate no upper limit to the heating capacity. '
-            'Note that setting this to None will trigger the default ("autosize").'
+            'be a NoLimit boject to indicate no upper limit to the heating capacity.'
     )
 
-    @validator('heating_limit')
-    def check_heating_limit(cls, v):
-        if v is not None and not isinstance(v ,float) and v != 'autosize':
-            raise ValueError( '"{}" is not a valid entry for heating_limit'.format(v))
-
-
-    cooling_limit: Union[float, str] = Field(
-        'autosize',
+    cooling_limit: Union[float, Autosize, NoLimit] = Field(
+        Autosize(),
         ge=0,
         description='A number for the maximum cooling capacity in Watts. This '
-            'can also be the text "autosize" to indicate that the capacity should '
-            'be determined during the sizing calculation. This can also '
-            'be the text "NoLimit" to indicate no upper limit to the cooling capacity. '
-            'Note that setting this to None will trigger the default ("autosize").'
+            'can also be an Autosize object to indicate that the capacity should '
+            'be determined during the EnergyPlus sizing calculation. This can also '
+            'be a NoLimit boject to indicate no upper limit to the cooling capacity.'
     )
 
-    @validator('cooling_limit')
-    def check_cooling_limit(cls, v):
-        if v is not None and not isinstance(v, float) and v != 'autosize':
-            raise ValueError( '"{}" is not a valid entry for cooling_limit'.format(v))
-
     heating_availability: str = Field(
         None,
         min_length=1,

honeybee_schema/energy/schedule.py

@@ -5,6 +5,7 @@
 import datetime
 
 from ._base import NamedEnergyBaseModel, DatedBaseModel
+from ..altnumber import NoLimit
 
 
 class ScheduleNumericType (str, Enum):
@@ -35,14 +36,14 @@ class ScheduleTypeLimit(NamedEnergyBaseModel):
 
     type: constr(regex='^ScheduleTypeLimit$') = 'ScheduleTypeLimit'
 
-    lower_limit: float = Field(
-        default=None,
-        description='Lower limit for the schedule type is entered.'
+    lower_limit: Union[NoLimit, float] = Field(
+        default=NoLimit(),
+        description='Lower limit for the schedule type or NoLimit.'
     )
 
-    upper_limit: float = Field(
-        default=None,
-        description='Upper limit for the schedule type is entered.'
+    upper_limit: Union[NoLimit, float] = Field(
+        default=NoLimit(),
+        description='Upper limit for the schedule type or NoLimit.'
     )
 
     numeric_type: ScheduleNumericType = ScheduleNumericType.continuous