Merge pull request #46 from DiamondLightSource/combo-box

Add allowed values for creating combo box widgets

Author: GDYendell

src/fastcs/attributes.py

@@ -117,12 +117,19 @@ def __init__(
         access_mode=AttrMode.WRITE,
         group: str | None = None,
         handler: Sender | None = None,
+        allowed_values: list[str] | None = None,
     ) -> None:
         super().__init__(datatype, access_mode, group, handler)  # type: ignore
         self._process_callback: AttrCallback[T] | None = None
         self._write_display_callback: AttrCallback[T] | None = None
         self._sender = handler
 
+        self._allowed_values = allowed_values
+
+    @property
+    def allowed_values(self) -> list[str] | None:
+        return self._allowed_values
+
     async def process(self, value: T) -> None:
         if self._write_display_callback is not None:
             await self._write_display_callback(self._datatype.dtype(value))
@@ -156,8 +163,9 @@ def __init__(
         access_mode=AttrMode.READ_WRITE,
         group: str | None = None,
         handler: Handler | None = None,
+        allowed_values: list[str] | None = None,
     ) -> None:
-        super().__init__(datatype, access_mode, group, handler)  # type: ignore
+        super().__init__(datatype, access_mode, group, handler, allowed_values)  # type: ignore
 
     async def process(self, value: T) -> None:
         await self.set(value)

src/fastcs/backends/epics/gui.py

@@ -6,6 +6,7 @@
 from pvi.device import (
     LED,
     ButtonPanel,
+    ComboBox,
     Component,
     Device,
     Grid,
@@ -27,7 +28,7 @@
 
 from fastcs.attributes import Attribute, AttrR, AttrRW, AttrW
 from fastcs.cs_methods import Command
-from fastcs.datatypes import Bool, DataType, Float, Int, String
+from fastcs.datatypes import Bool, Float, Int, String
 from fastcs.exceptions import FastCSException
 from fastcs.mapping import Mapping, SingleMapping, _get_single_mapping
 from fastcs.util import snake_to_pascal
@@ -55,27 +56,33 @@ def _get_pv(self, attr_path: list[str], name: str):
         return f"{attr_prefix}:{name.title().replace('_', '')}"
 
     @staticmethod
-    def _get_read_widget(datatype: DataType) -> ReadWidget:
-        match datatype:
+    def _get_read_widget(attribute: AttrR) -> ReadWidget:
+        match attribute.datatype:
             case Bool():
                 return LED()
             case Int() | Float():
                 return TextRead()
             case String():
                 return TextRead(format=TextFormat.string)
-            case _:
+            case datatype:
                 raise FastCSException(f"Unsupported type {type(datatype)}: {datatype}")
 
     @staticmethod
-    def _get_write_widget(datatype: DataType) -> WriteWidget:
-        match datatype:
+    def _get_write_widget(attribute: AttrW) -> WriteWidget:
+        match attribute.allowed_values:
+            case allowed_values if allowed_values is not None:
+                return ComboBox(choices=allowed_values)
+            case _:
+                pass
+
+        match attribute.datatype:
             case Bool():
                 return ToggleButton()
             case Int() | Float():
                 return TextWrite()
             case String():
                 return TextWrite(format=TextFormat.string)
-            case _:
+            case datatype:
                 raise FastCSException(f"Unsupported type {type(datatype)}: {datatype}")
 
     def _get_attribute_component(
@@ -86,8 +93,8 @@ def _get_attribute_component(
 
         match attribute:
             case AttrRW():
-                read_widget = self._get_read_widget(attribute.datatype)
-                write_widget = self._get_write_widget(attribute.datatype)
+                read_widget = self._get_read_widget(attribute)
+                write_widget = self._get_write_widget(attribute)
                 return SignalRW(
                     name=name,
                     write_pv=pv,
@@ -96,10 +103,10 @@ def _get_attribute_component(
                     read_widget=read_widget,
                 )
             case AttrR():
-                read_widget = self._get_read_widget(attribute.datatype)
+                read_widget = self._get_read_widget(attribute)
                 return SignalR(name=name, read_pv=pv, read_widget=read_widget)
             case AttrW():
-                write_widget = self._get_write_widget(attribute.datatype)
+                write_widget = self._get_write_widget(attribute)
                 return SignalW(name=name, write_pv=pv, write_widget=write_widget)
 
     def _get_command_component(self, attr_path: list[str], name: str):

tests/backends/epics/test_gui.py

@@ -1,5 +1,6 @@
 from pvi.device import (
     ButtonPanel,
+    ComboBox,
     SignalR,
     SignalRW,
     SignalW,
@@ -32,18 +33,20 @@ def test_get_components(mapping):
             read_pv="DEVICE:ReadInt",
             read_widget=TextRead(),
         ),
-        SignalR(
-            name="ReadString",
-            read_pv="DEVICE:ReadString",
-            read_widget=TextRead(format="string"),
-        ),
         SignalRW(
             name="ReadWriteFloat",
             write_pv="DEVICE:ReadWriteFloat",
             write_widget=TextWrite(),
             read_pv="DEVICE:ReadWriteFloat_RBV",
             read_widget=TextRead(),
         ),
+        SignalRW(
+            name="StringEnum",
+            read_pv="DEVICE:StringEnum_RBV",
+            read_widget=TextRead(format="string"),
+            write_pv="DEVICE:StringEnum",
+            write_widget=ComboBox(choices=["red", "green", "blue"]),
+        ),
         SignalW(
             name="WriteBool",
             write_pv="DEVICE:WriteBool",

tests/backends/tango/test_dsr.py

@@ -11,14 +11,14 @@ def test_collect_attributes(mapping):
     # Check that attributes are created and of expected type
     assert list(attributes.keys()) == [
         "ReadInt",
-        "ReadString",
         "ReadWriteFloat",
+        "StringEnum",
         "WriteBool",
     ]
     assert attributes["ReadInt"].attr_write == AttrWriteType.READ
     assert attributes["ReadInt"].attr_type == CmdArgType.DevLong64
-    assert attributes["ReadString"].attr_write == AttrWriteType.READ
-    assert attributes["ReadString"].attr_type == CmdArgType.DevString
+    assert attributes["StringEnum"].attr_write == AttrWriteType.READ_WRITE
+    assert attributes["StringEnum"].attr_type == CmdArgType.DevString
     assert attributes["ReadWriteFloat"].attr_write == AttrWriteType.READ_WRITE
     assert attributes["ReadWriteFloat"].attr_type == CmdArgType.DevDouble
     assert attributes["WriteBool"].attr_write == AttrWriteType.WRITE

tests/conftest.py

@@ -25,7 +25,7 @@ class TestController(Controller):
     read_int: AttrR = AttrR(Int())
     read_write_float: AttrRW = AttrRW(Float())
     write_bool: AttrW = AttrW(Bool())
-    read_string: AttrR = AttrR(String())
+    string_enum: AttrRW = AttrRW(String(), allowed_values=["red", "green", "blue"])
 
     @command()
     async def go(self):