String DataType

src/fastcs/backends/epics/gui.py

@@ -16,14 +16,15 @@
     SignalRW,
     SignalW,
     SignalX,
+    TextFormat,
     TextRead,
     TextWrite,
     Tree,
     WriteWidget,
 )
 
 from fastcs.attributes import Attribute, AttrR, AttrRW, AttrW
-from fastcs.datatypes import Bool, DataType, Float, Int
+from fastcs.datatypes import Bool, DataType, Float, Int, String
 from fastcs.exceptions import FastCSException
 from fastcs.mapping import Mapping
 
@@ -62,6 +63,8 @@
                 return LED()
             case Int() | Float():
                 return TextRead()
+            case String():
+                return TextRead(format=TextFormat.string)
             case _:
                 raise FastCSException(f"Unsupported type {type(datatype)}: {datatype}")
 
@@ -72,6 +75,8 @@
                 return CheckBox()
             case Int() | Float():
                 return TextWrite()
+            case String():
+                return TextWrite(format=TextFormat.string)
             case _:
                 raise FastCSException(f"Unsupported type {type(datatype)}: {datatype}")
 

src/fastcs/backends/epics/ioc.py

@@ -7,7 +7,7 @@
 
 from fastcs.attributes import AttrR, AttrRW, AttrW
 from fastcs.backend import Backend
-from fastcs.datatypes import Bool, DataType, Float, Int
+from fastcs.datatypes import Bool, DataType, Float, Int, String
 from fastcs.exceptions import FastCSException
 from fastcs.mapping import Mapping
 
@@ -25,6 +25,8 @@
             return builder.longIn(pv_name)
         case Float(prec):
             return builder.aIn(pv_name, PREC=prec)
+        case String():
+            return builder.longStringIn(pv_name)
         case _:
             raise FastCSException(f"Unsupported type {type(datatype)}: {datatype}")
 
@@ -54,6 +56,10 @@
             return builder.aOut(
                 pv_name, always_update=True, on_update=on_update, PREC=prec
             )
+        case String():
+            return builder.longStringOut(
+                pv_name, always_update=True, on_update=on_update
+            )
         case _:
             raise FastCSException(f"Unsupported type {type(datatype)}: {datatype}")
 

src/fastcs/datatypes.py

@@ -4,7 +4,7 @@
 from dataclasses import dataclass
 from typing import Awaitable, Callable, Generic, TypeVar
 
-T = TypeVar("T", int, float, bool)
+T = TypeVar("T", int, float, bool, str)
 ATTRIBUTE_TYPES: tuple[type] = T.__constraints__  # type: ignore
 
 
@@ -42,3 +42,10 @@
     @property
     def dtype(self) -> type[bool]:
         return bool
+
+
+@dataclass(frozen=True)
+class String(DataType[str]):
+    @property
+    def dtype(self) -> type[str]:
+        return str